Neuroprotective Effects of Cannabinoids in Brain Ischemia
Brain ischemia, also called cerebral ischemia, means part of the brain is not getting enough blood, and so not enough oxygen. Research on cannabis and brain ischemia is still limited to experiments in animals and on lab tissue: no trial in people has tested whether medical cannabis helps. Cannabis does not treat an ischemic attack or a stroke.
Built on the published studies listed in the references at the end of this page: almost all in animals or on lab tissue, and one in people that did not test cannabis. See the evidence by type.
Stroke symptoms? Call 911 first
If symptoms start suddenly, treat them as a stroke until a hospital says otherwise. The clot-dissolving drug used for ischemic stroke works only within a short window, about 4.5 hours from the first symptom, and only an estimated 3 to 8.5% of new stroke patients receive it, largely because they arrive too late [1]. Brain scans, clot removal (thrombectomy) and the decision between them happen only in a hospital [2] [3].
Many hospitals teach the warning signs as BE FAST, which adds balance and eyes to the familiar F.A.S.T. check [2] [4].
-
Balance
Sudden loss of balance or coordination, trouble walking, or sudden dizziness.
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Eyes
Sudden blurred, double or lost vision in one or both eyes.
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Face
One side of the face droops or goes numb. Ask the person to smile.
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Arms
One arm or leg is weak or numb. Ask them to raise both arms: does one drift down?
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Speech
Slurred or strange speech, or trouble understanding. Ask them to repeat a short sentence.
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Time
Call 911 at once and note when symptoms started: doctors need that time to choose treatment.
While you wait, do not drive yourself and do not take aspirin or any other medicine unless the dispatcher tells you to. A stroke can be caused by bleeding rather than a clot, and only a scan tells the two apart [3].
A transient ischemic attack (TIA, often called a “mini-stroke”) has the same signs but passes on its own, often within minutes. It still needs a medical check the same day, because it can be the warning before a larger stroke [4] [3].
Living with chronic brain ischemia: why it wears you down
Chronic brain ischemia rarely announces itself the way a stroke does. More often it is a slow list: you stand up and the room tilts, the word you need arrives a second late, an afternoon headache becomes routine, and every new tingle in a hand raises the same question. Is this another one? The scan report calls it “small vessel disease” or “chronic ischemic changes,” words that sound serious and explain very little.
That uncertainty is tiring in its own right. Many people leave the appointment with a blood pressure target, a daily pill and a follow-up in six months. It is sound advice, and it can still leave you feeling that nobody looked at the symptoms you actually live with.
What bothers you most?
Choose one to see what doctors usually do about it and what cannabinoid research has, and has not, looked at.
Choose one above to see what usually helps and what the research says about it.
Dizziness: doctors check blood pressure lying down and standing up, heart rhythm, and medicines that may push pressure too low; balance therapy helps many people. The cannabinoid studies in brain ischemia did not measure dizziness at all, and THC itself can cause light-headedness on standing (see safety after a stroke).
Memory & focus: doctors look for causes that can be treated, such as poor sleep, sleep apnea, low vitamin B12, thyroid problems, low mood or a medicine side effect, and control blood pressure to protect what remains. The cannabinoid studies measured damaged brain tissue in rats and mice, not memory in people. What the scan words mean is covered in what brain ischemia is.
Headaches: a new or changed headache pattern deserves its own check-up, and chronic headache is diagnosed and treated as its own condition. None of the brain ischemia studies looked at headache. For that research, read headache and medical cannabis.
Tiredness: fatigue is common after a stroke and with small vessel disease, and it is often tied to poor sleep, low mood or medicines, which doctors treat first, along with gradually increased activity. No cannabinoid study here measured fatigue, and THC can add drowsiness rather than energy.
Fear of another stroke: the worry is understandable, and the strongest answer to it is prevention that is known to work: blood pressure control, antiplatelet or anticoagulant medicine when prescribed, statins, and knowing the warning signs. See what treatment can and cannot reverse.
What is brain ischemia?
Brain ischemia (cerebral ischemia) is a shortage of blood flow to part or all of the brain. Without enough blood, brain cells run short of oxygen and glucose, stop working within minutes and begin to die if flow is not restored. It can strike suddenly, as a transient ischemic attack or an ischemic stroke, or build slowly as small vessels narrow [3].
The sudden form is common and serious: stroke causes about 6.5 million deaths worldwide each year [5], and most strokes are ischemic, caused by a blocked artery rather than by bleeding [3]. The slow form is quieter. Doctors often find it on a scan done for something else, as patches of tissue that have lost part of their blood supply over the years.
Focal ischemia
What it is: one artery, or one small branch, is narrowed or blocked, so one area of the brain loses blood.
What it causes: symptoms that match that area: one weak side, lost speech, a gap in vision.
Typical forms: TIA, ischemic stroke, small “lacunar” strokes, chronic small vessel disease.
Global ischemia
What it is: blood flow to the whole brain drops at once, as when the heart stops or blood pressure collapses.
What it causes: loss of consciousness within seconds; the most sensitive areas, including memory centers, are hurt first.
Typical forms: brain injury after cardiac arrest, drowning or severe shock.
Ischemia, TIA or stroke?
The three words describe one process at different stages, and the difference decides what you do next.
| Question | Brain ischemia | TIA | Ischemic stroke |
|---|---|---|---|
| What it is | The general term: too little blood reaching brain tissue | A brief blockage that clears before tissue dies | A blockage that lasts long enough to kill brain tissue |
| How long | Seconds to years, depending on the form | Usually minutes, always gone within a day | Symptoms persist; recovery takes weeks to months |
| Tissue damage | From none to permanent | None visible on a scan, by definition | An infarct, an area of dead tissue, seen on MRI or CT |
| What to do | Sudden symptoms: 911. Scan finding: a planned visit | A medical check the same day | Call 911 immediately |
What does “ischemic changes” on my MRI mean?
Pick the phrase that appears in your report. It is usually in the “Impression” section at the end.
Choose the phrase from your report to see it in plain words, with a question to take to the doctor who ordered the scan.
Mild ischemic changes: a few small spots where the tiniest vessels have supplied less blood over time. They become more common with age and with high blood pressure. Ask: “Do these change anything about my blood pressure or cholesterol targets?”
Chronic microvascular changes: another name for small vessel disease, the slow wear of the brain’s smallest arteries. It is the most common form of chronic brain ischemia. Ask: “Is this more than expected for my age, and what should we treat more aggressively?”
White matter hyperintensities: bright spots on certain MRI sequences in the brain’s wiring, the white matter. Most often they reflect small vessel disease, but migraine and inflammation can look similar. Ask: “What do you think caused these, and do we need a follow-up scan?”
Lacunar infarct: a small old stroke deep in the brain, sometimes one that caused no symptoms you noticed. It counts as a stroke for prevention purposes. Ask: “Should I now be on stroke-prevention medicine?”
Restricted diffusion (DWI): the MRI sign of a fresh stroke, usually days old or less. If this phrase is new to you and you are not already under care, call the doctor who ordered the scan today. Ask: “Do I need to be seen urgently?”
Brain injury from ischemia, oxygen loss or trauma
Doctors separate brain injury by its cause. Ischemic injury comes from too little blood flow, usually through a blocked artery. Anoxic or hypoxic injury comes from too little oxygen in the blood itself, as after cardiac arrest, drowning or choking; it often overlaps with global ischemia, because the heart stops pumping at the same time. Traumatic brain injury is caused by a blow or a jolt to the head, and swelling after it can cut blood flow and add ischemia on top.
The cause matters because the treatment, the course of recovery and the research behind each type differ. Traumatic and anoxic injury have their own page: brain injuries and medical cannabis.
Brain ischemia symptoms and causes
Symptoms depend on which part of the brain is short of blood, and on how fast it happens. Sudden symptoms are an emergency; the same functions can also fade slowly over months with chronic small vessel disease [4] [3].
Sudden or gradual?
Show one column at a time to compare.
| Area | Comes on suddenly | Builds up over months |
|---|---|---|
| Movement | Weakness or numbness of the face, arm or leg on one side call 911 | Slower, shuffling steps; clumsier hands |
| Speech | Slurred words, or trouble finding or understanding words call 911 | Words come more slowly; conversations are harder to follow |
| Vision | Loss of vision in one eye or one side, or double vision call 911 | Rarely affected alone |
| Balance | Sudden dizziness, staggering, loss of coordination call 911 | Unsteadiness, more falls, light-headedness on standing |
| Thinking & memory | Sudden confusion or a severe headache with no known cause call 911 | Slower thinking, trouble planning and keeping attention |
| Mood | Sudden change in behavior alongside other signs call 911 | Low mood, apathy, irritability |
What causes it
Anything that narrows an artery, blocks it or drops the pressure that pushes blood through it can starve brain tissue [3].
Narrowed arteries
Fatty plaque (atherosclerosis) in the neck or brain arteries slows flow and can break off.
A clot from the heart
Atrial fibrillation and some valve problems form clots that travel to the brain (embolism).
Small vessel disease
Years of high blood pressure and diabetes thicken the brain’s smallest arteries.
The heart stops or pressure collapses
Cardiac arrest or severe shock cuts flow to the whole brain at once (global ischemia).
Blood disorders and vessel tears
Clotting disorders or a tear in a neck artery wall (dissection), more common in younger people.
Risk factors
- High blood pressure, the strongest single risk factor for both stroke and small vessel disease [3].
- Atrial fibrillation and other heart rhythm or valve problems.
- Diabetes, high cholesterol and obesity.
- Smoking, including the smoke of any burned plant material.
- A previous TIA or stroke, and a family history of early stroke.
- Older age, physical inactivity and heavy drinking.
Is brain ischemia dangerous?
It depends on the form. Sudden ischemia is dangerous every time: it can become a permanent stroke within minutes to hours, which is why the warning signs come first on this page. Chronic small vessel changes progress slowly, and treating their causes can slow them, but over years they raise the risk of stroke, falls and memory problems. Neither form is something to watch and wait on without a doctor.
Could medical cannabis be worth discussing in your situation?
Fourteen short questions about what doctors found, how you feel now and the medicines you take. Your answers stay on this page and show what to bring to a physician.
14 questions · about a minute · your answers stay in this browser
How is brain ischemia diagnosed?
Diagnosis starts with what happened and when, a neurological exam and a blood pressure reading, then imaging. Sudden symptoms get a brain scan within minutes of arriving at the hospital; chronic changes are usually found on a planned MRI [3].
Which test is on your referral or report?
Choose the test named in your referral or report.
Choose a test above to see what it shows, when it is used and what it can miss.
CT scan
Bleeding in the brain right away; a large stroke after some hours; old strokes.
First, in the emergency room: it is fast and rules out bleeding before a clot-dissolving drug is given.
Early and small ischemia. A CT can look normal in the first hours of a stroke.
MRI and diffusion imaging (DWI)
Fresh ischemia within minutes to hours on the DWI sequence, plus old small strokes and white matter changes.
For a suspected TIA or stroke when time allows, and to look for chronic ischemia behind dizziness or memory changes.
It takes longer, and some pacemakers and metal implants rule it out.
Perfusion scans
How much blood each area receives, and which tissue is still savable (the penumbra).
In stroke centers, to decide on clot removal beyond the earliest hours.
It is not a routine test for chronic symptoms.
Ultrasound (Doppler)
Narrowing in the carotid arteries of the neck; a heart ultrasound looks for a clot source in the heart.
After a TIA or stroke, to find the cause and plan prevention.
Arteries inside the skull are seen only partly.
Angiography (CTA, MRA or catheter)
A map of the arteries: blockages, narrowing and tears.
In an emergency to locate a clot, and when surgery or a stent is being planned.
It needs contrast dye, and the catheter version is an invasive procedure.
ICD-10 codes you may see
The diagnosis code on a visit summary or discharge paper is how your diagnosis travels between doctors, insurers and state programs.
| Code | What it means | Where it appears |
|---|---|---|
| I63.x | Cerebral infarction (ischemic stroke); the characters after the dot name the artery and the cause | Hospital discharge summary after a stroke |
| G45.9 | Transient cerebral ischemic attack, unspecified | Emergency room and clinic notes after a TIA |
| I67.82 | Cerebral ischemia | Notes describing ischemia without a completed stroke |
| I67.9 | Cerebrovascular disease, unspecified | Referrals and follow-up for chronic changes on a scan |
| I69.3- | Lasting effects (sequelae) of cerebral infarction, such as weakness or speech problems | Rehabilitation and primary care notes after a stroke |
| Z86.73 | Personal history of TIA or cerebral infarction without lasting deficits | Records of people who recovered fully |
For a medical card, this matters more than it seems: state programs go by the diagnosis in your records, not by symptoms. Ask for the visit summary or discharge papers that show the code, and keep a copy with your scan report.
Chronic brain ischemia treatment: can it be reversed?
Treatment goes after the cause: keep blood flowing, prevent the next clot and protect the tissue that is still healthy. For an acute ischemic stroke that means a clot-dissolving drug within about 4.5 hours, or removing the clot [1]. For chronic ischemia it means long-term control of everything that narrows vessels [3]. None of it is dramatic, and all of it works better the earlier it starts.
Blood pressure control
The single most effective step against both new strokes and the growth of small vessel changes.
Antiplatelets or anticoagulants
Aspirin-type drugs after most ischemic events; blood thinners when atrial fibrillation is the cause.
Statins
Lower cholesterol and steady the plaque in arteries, so pieces are less likely to break off.
Blood sugar
Keeping diabetes in range slows the damage to the brain’s smallest vessels.
Rehabilitation
Physical, speech and occupational therapy retrain healthy brain areas to take over lost work.
Daily habits
Stopping smoking, regular movement, less alcohol and treated sleep apnea all lower the risk.
What can recover
Tissue around a fresh stroke (the penumbra) can be saved if blood flow returns fast enough. TIA symptoms resolve completely. Many functions lost to a stroke come back partly or fully with rehabilitation, most quickly in the first months.
What usually stays
Brain tissue that has died does not grow back, and chronic small vessel changes on a scan do not disappear. The goal there is to stop new damage and let healthy areas compensate.
Prognosis
The questions people ask most, answered as far as general medicine allows. Your own outlook is a conversation with your neurologist.
How long can you live with brain ischemia?
There is no single number. Many people with mild chronic ischemic changes live a normal life span, especially when blood pressure and other risks are treated. After a stroke, the outlook depends on its size and location, your age and other conditions, and how quickly treatment started. None of the research cited on this page reports survival figures, so we do not quote any.
How long does ischemia last?
A TIA usually lasts minutes and is gone within a day. In a stroke, blood flow may return within hours, but the damage stays, and recovery takes weeks to months. Chronic ischemia continues for as long as its causes do, which is why controlling them is the treatment.
Can brain ischemia be cured?
Damage that has already happened is not undone by any medicine, cannabis included. What can be achieved is real, though: new damage can be prevented or slowed, and lost function can return through rehabilitation as healthy parts of the brain take over.
Can it come back?
Yes. After a TIA or stroke the risk of another one is highest in the first weeks and months, and prevention medicines and risk-factor control lower it [3]. Any new sudden symptom means calling 911, even if you have had the same thing before.
What does research say about cannabis and brain ischemia?
Very little that applies to patients yet. Every study cited here that tested a cannabinoid against brain ischemia was done in rats, mice or gerbils, or on tissue in a lab dish. Many of them found less damage, which is why scientists keep looking. None of them can tell you what cannabis would do in your brain.
| Level | What exists for brain ischemia | What it can and cannot tell you |
|---|---|---|
| Trials in people | None among the studies cited here. | Would show benefit and harm in patients. That evidence does not exist yet. |
| Studies in people | One cohort of California births about risk factors for newborn brain injury from low oxygen [7]. Not a cannabis study | Shows links, not causes; says nothing about cannabis as a treatment. |
| Lab tissue | Four studies on rat brain slices, mouse neurons and a human blood-brain barrier model [8][9][10][11]. | Shows mechanisms in a dish, without blood flow or a whole body. |
| Animals | Twelve studies in rats, mice and gerbils [12][13][14][5][1][15][16][17][18][19][20][21]. | Shows whether damage shrinks in an animal model; doses and timing do not transfer to people. |
Browse the studies yourself
Every study cited on this page, in plain words. Several tested treatments that are not cannabis at all but act on the same receptors; they are marked.
Propofol, an anesthetic, raised the brain’s own cannabinoids
In 56 rats with a blocked brain artery and in oxygen-starved neurons, propofol raised anandamide and 2-AG and reduced injury; blocking the CB1 receptor took the protection away [12].
Kaempferol, a plant flavonoid, shifted brain fats after clamped arteries
In a study of 76 rats, a single 40 mg dose before neck arteries were clamped and reopened changed endocannabinoid-related signals in the cortex; one marker of fat oxidation fell by 72.3% against untreated rats [13].
CBD protected brain slices, possibly through the TRPV2 channel
In rat hippocampal slices starved of oxygen and glucose for 30 minutes, CBD limited damage and changed how the brain’s immune cells behaved; THC was tested alongside it, with mixed results overall [8].
Blocking a glutamate receptor protected neurons through CB1
After 5 minutes of blocked neck arteries, the drug LY367385 raised calming GABA output up to 21-fold and left only 7% loss in a vulnerable cell layer; the effect ran through CB1 receptors [14].
Risk factors for newborn brain injury from low oxygen
Across 2,994,892 California births from 2011 to 2017, 6,857 babies had neonatal encephalopathy; maternal infection, preeclampsia, diabetes and substance-related diagnoses were linked to higher risk. Associations only [7].
A CBD-rich extract reduced injury; a THC-rich one worsened it
In oxygen- and glucose-starved slices, the CBD-rich extract cut damage by up to 45%, while the THC-rich extract increased it by 145%; a CB1 blocker removed the THC harm [9].
CBD and beta-caryophyllene in mice with a permanent stroke
In a study of 80 mice, single doses of CBD or of beta-caryophyllene, a terpene found in cannabis and black pepper, at 30 mg/kg reduced stroke size measured three days later [5].
A synthetic CB1 activator, ACEA, limited injury after flow returned
In rats (6 per group) with 1.5 hours of a blocked brain artery and in oxygen-starved cells, ACEA reduced injury through a pathway that controls mitochondria; CB1 blockers canceled the effect [1].
Orexin-A protected neurons by raising 2-AG
Orexin-A, a brain hormone tied to wakefulness, protected oxygen-starved neurons by raising the body’s own cannabinoid 2-AG and switching on CB1 [10].
The brain’s cannabinoid system reacts to a brief loss of blood flow
After neck arteries were clamped and reopened, rats had more endocannabinoids and roughly double the CB1 receptor protein (+101%) in the frontal cortex compared with sham-operated rats [15].
A mitochondrial marker of early cell damage
An antibody made against CB1 turned out to bind a mitochondrial protein, SLP2, whose shift inside mitochondria marked early damage in developing and adult mouse brains [16].
ACEA worked through CB1 receptors inside mitochondria
The CB1 activator ACEA increased CB1 receptors on mitochondria and protected neurons against injury from blocked and restored blood flow [17].
Electroacupuncture pretreatment acted through CB1
Electroacupuncture before global ischemia reduced injury and nerve cell death in mice, an effect linked to CB1 receptors and the GluR2 protein [18].
The body’s own cannabinoids tightened a model blood-brain barrier
In human cells grown as a model of the blood-brain barrier, anandamide and related compounds made the barrier less leaky [11].
Mastic tree oil and the cortex after clamped arteries
Essential oil of Pistacia lentiscus, the mastic tree, was tested in rats whose neck arteries were clamped and reopened, with effects on endocannabinoid-related signals in the cortex [19].
Tetrahydrocurcumin, a turmeric compound, after ischemia
Not THC, despite the shared abbreviation: tetrahydrocurcumin eased cell self-digestion (autophagy) and blood-brain barrier damage after ischemia in mice with high homocysteine [20].
A CB2 activator protected the brain’s small vessels
The selective CB2 agonist O-1966 eased problems in the smallest blood vessels during blocked and restored blood flow to the brain [21].
No studies of this type are cited on this page.
How has the research grown over the years?
Each mark is one study cited on this page, stacked above the year it was published, with the count on top. Squares are studies in people; circles are studies in animals or lab tissue. The filter above dims the studies outside your choice.
PeopleAnimals or lab tissue
- 12009
- 22012
- 32015
- 12016
- 12017
- 22020
- 22021
- 32022
- 12025
- 12026
Show as a table
| Year | Animal | Lab tissue | People |
|---|---|---|---|
| 2009 | 1 | 0 | 0 |
| 2012 | 2 | 0 | 0 |
| 2015 | 2 | 1 | 0 |
| 2016 | 1 | 0 | 0 |
| 2017 | 1 | 0 | 0 |
| 2020 | 1 | 1 | 0 |
| 2021 | 1 | 1 | 0 |
| 2022 | 1 | 1 | 1 |
| 2025 | 1 | 0 | 0 |
| 2026 | 1 | 0 | 0 |
Why do researchers look at cannabinoids in brain ischemia?
Your body makes its own cannabis-like messengers, the endocannabinoids anandamide and 2-AG, and has receptors for them: CB1, found mostly on nerve cells, and CB2, found mostly on immune cells and blood vessels. Together they form the endocannabinoid system, explained in our guide to the endocannabinoid system. When blood flow to the brain is cut and restored, that system switches on in animals, and that is what drew researchers to it [15].
What happens in the first hours
Damage from ischemia unfolds as a chain of steps. Choose one to see what goes wrong and where cannabinoids were tested, always in animals or lab tissue.
Choose a step above to see what happens and what was tested.
1. Blood flow stops. Cells lose oxygen and glucose within seconds and stop firing within minutes. Labs copy this as “oxygen-glucose deprivation”; a CBD-rich extract protected rat brain slices in that model [9].
2. Glutamate surge. Starved neurons release too much glutamate, an exciting messenger, and overstimulate their neighbors to death. In gerbils, strengthening calming GABA signals through CB1 receptors protected vulnerable neurons [14].
3. Inflammation. The brain’s immune cells, microglia, swarm the injured area. CBD changed how microglia behaved in rat brain slices [8], and CBD or beta-caryophyllene reduced stroke size in mice [5].
4. Oxidative stress. When blood flow returns, it brings a burst of damaging oxygen molecules. Fat oxidation products in the rat cortex rose by 57% after flow was cut and restored [15]; switching on CB1 receptors protected mitochondria, the cell’s power plants, in rats [1][17].
5. Cell death. Cells that cannot recover die over hours to days, and the injury grows. Most of the animal studies here measured the final size of that dead area, the infarct [5][12].
Cannabis compounds tested
Other treatments that act through the same system
- Propofol, an anesthetic [12]
- Kaempferol, a plant flavonoid [13]
- Orexin-A, a brain hormone [10]
- Electroacupuncture [18]
- LY367385, a glutamate receptor blocker [14]
These are not cannabis. They matter here only because they worked through the CB1 receptor.
THC vs CBD in brain ischemia research
THC and CBD come from the same plant and act very differently, so a result for one does not carry over to the other. The clearest side-by-side test so far used whole cannabis extracts on rat brain tissue in a dish [9]. It is a lab result, and it is worth knowing because the two extracts pointed in opposite directions.
Compare the two extracts
Choose one to bring it forward. Both numbers come from the same experiment.
Follow-up work tied CBD’s protection to the TRPV2 channel and to changes in microglia [8], and drugs that block TRPV2, the serotonin 5-HT1A receptor or PPAR-gamma each canceled it [9]. THC’s harm ran through CB1: with CB1 blocked, THC no longer worsened the injury [9]. The authors conclude that THC may carry risks in the acute phase of ischemia, and that high-THC products may cancel out what CBD did [9].
How the experiment was done
Slices of rat hippocampus, the memory center most sensitive to ischemia, were deprived of oxygen and glucose for 30 minutes and examined after 24 hours [9]. The FM2 extract contained 8.2 mg/mL of CBD and 4.6 mg/mL of THC; Bedrocan contained 16.69 mg/mL of THC and 0.66 mg/mL of CBD [9]. FM2 reached its largest effect at 28 µg/mL, and Bedrocan caused the harm at 1.81 µg/mL [9]. The CB1 blocker AM251 removed the THC harm [9].
In the follow-up study, pure CBD was tested at 10 µM and pure THC at 1 µM, after the same 30 minutes of deprivation and 24 hours of recovery [8].
These are concentrations in a lab dish, not doses for a person, and they cannot be turned into one.
Does the way you use cannabis matter?
Cannabis is not only smoked. People also vape it, swallow it as gummies, capsules or oils, hold drops under the tongue, or put it on the skin. For someone with brain ischemia, the form changes some risks and leaves others exactly where they were. The studies above injected compounds into animals or added them to tissue in a dish, so they say nothing about any form a patient would use. This section explains the differences; it does not recommend a form.
How do you use it, or how would you?
Choose the closest; most people combine more than one.
Choose a form above to see what is specific to it. What is true of every form stays below.
Specific to smoking
Joints, blunts, pipes and bongs burn plant material. Smoke from any burning plant carries carbon monoxide and fine particles into the blood, and smoking is a recognized stroke risk factor [3]. The effect starts within minutes and is hard to measure in milligrams.
Specific to vaping and dabbing
Dry-herb vaporizers, oil pens and cartridges avoid burning, but a hot aerosol still travels the same airways and THC reaches the blood just as fast. Concentrates used for dabbing, such as wax, shatter or rosin, are very strong, which makes the dose, and THC’s effect on heart rate and blood pressure, harder to control.
Shared devices
A pipe, vape or joint passed between people also passes on colds and other infections, an avoidable strain during recovery.
Specific to edibles and capsules
Gummies, chocolates, drinks, capsules and swallowed oils avoid smoke entirely. They act slowly, often after an hour or more, and last for hours, because the liver processes them before they reach the blood. The classic mistake is a second piece “because the first did nothing,” followed hours later by dizziness and a fall.
Specific to tinctures and sprays
Drops held under the tongue and mouth sprays skip the lungs and are measured by the drop or spray. Part of each dose is still swallowed and passes through the liver, where it meets the same enzymes that handle blood thinners and other heart medicines.
Specific to topicals and patches
Creams and balms act mainly where they are applied and are not a way to reach the brain. Transdermal patches are different: they deliver cannabinoids into the blood, so their effects on the brain and on other medicines count like any other form.
Specific to prescription cannabinoids
Dronabinol (Marinol, Syndros), nabilone (Cesamet) and cannabidiol (Epidiolex) are FDA-approved prescription drugs with exact doses, filled at a pharmacy rather than bought with a medical card [22]. None of them is approved for brain ischemia or stroke.
True of every form
- THC acts on CB1 receptors in the brain and can cause dizziness and light-headedness on standing.
- It can change heart rate and blood pressure, the very numbers your stroke prevention depends on.
- Drowsiness and slower reactions add to any existing fall risk.
- Whatever reaches the blood passes through the liver and can change the levels of other medicines, blood thinners included.
- No driving after use.
Choosing a form is a conversation for the appointment, not a recommendation from this page.
All forms as a table
| Form | What it avoids | What remains |
|---|---|---|
| Smoking | Delay in onset | Smoke in the blood and airways, shared devices, hard-to-measure dose, all effects of THC |
| Vaping & dabbing | Burning plant material | Hot aerosol in the airways, very strong concentrates, shared devices, all effects of THC |
| Edibles & capsules | Smoke and vapor, shared devices | Slow, long effect, risk of a repeat dose, liver processing, interactions |
| Tinctures & sprays | Smoke and vapor, shared devices | Effects on the brain, partly swallowed dose, interactions |
| Topicals | Most effects on the brain | Skin reactions; no effect on brain symptoms |
| Transdermal patches | Smoke, vapor and swallowing | Effects on the brain, interactions, the same fall risk |
| Prescription cannabinoids | Unknown product content | Drowsiness, dizziness, interactions; not approved for brain ischemia |
Is cannabis safe after a stroke or with blood thinners?
Nobody can say yet. No study cited on this page gave cannabis to people after a stroke or alongside blood thinners, so there is no safety record for this group. What is known comes from how THC acts in general, and it weighs more after a stroke, when balance, blood pressure and medicines are already in play. The one ischemia-specific signal, from lab tissue, is that THC made injury worse [9].
Dizziness on standing
THC can lower blood pressure when you stand up. After a stroke, a few seconds of light-headedness is enough for a fall.
Blood pressure and heart rate swings
A faster pulse and shifting pressure work against the steady numbers stroke prevention aims for.
Falls
Weakness on one side plus dizziness or drowsiness adds up; on a blood thinner, a fall can also mean bleeding.
Drowsiness
Sedation can be mistaken for better sleep while daytime alertness and rehabilitation suffer.
Thinking slows
THC slows attention and memory for hours, which is hard to tell apart from the ischemia itself.
Driving
No driving after use. Many people are also told not to drive for a while after a stroke or TIA.
Medicines to check with a doctor
Open each one. None of these pairings has been tested in people with brain ischemia, and each tag says so.
Blood thinners (warfarin, apixaban, rivaroxaban, dabigatran) no data in people
Warfarin and several newer blood thinners are cleared by liver enzymes that CBD and THC also use. A change in their level can mean more bleeding or less protection against clots. The studies on this page did not test these pairings. Any cannabis product, CBD included, should be reviewed against your blood thinner, and people on warfarin may need closer INR checks if anything changes.
Antiplatelets (aspirin, clopidogrel) no data in people
Clopidogrel only works after a liver enzyme switches it on, and cannabinoids can influence enzymes of that family. Whether that weakens clopidogrel in practice has not been studied in people with brain ischemia. Never stop an antiplatelet to try cannabis.
Statins (atorvastatin, simvastatin and others) no data in people
Several statins are broken down by the CYP3A4 enzyme, which cannabinoids may slow. Higher statin levels can mean more muscle aches. Tell the physician which statin you take and at what dose.
Blood pressure medicines no data in people
THC can drop blood pressure on standing and raise the heart rate. Added to blood pressure drugs, that can mean dizziness and falls. A week of home readings, morning and evening, gives the physician something real to judge by.
Seizure medicines no data in people
Seizures can follow a stroke. CBD can raise the levels of some seizure medicines, which is why the prescription CBD drug Epidiolex is dosed under a doctor’s supervision [22]. Review every seizure medicine with the doctor who prescribes it before adding any cannabis product.
Many medicines at once (CYP450 liver enzymes) no data in people
CBD and THC are processed by the CYP450 family of liver enzymes, which also handles many heart, blood-thinning and seizure drugs. The interactions recorded in the lab studies here are between research drugs and receptors, for example a CB1 blocker that canceled THC’s harm in brain tissue [9]. They say nothing about your prescriptions; your physician checks those one by one.
Bring the full list to the appointment: prescriptions, over-the-counter pain relievers, supplements that also affect bleeding, such as fish oil or ginkgo, and anything taken “only sometimes.” That list, more than the diagnosis, decides whether cannabis is reasonable to discuss.
What we still don’t know
The gaps are most of the story here. This is what the studies themselves say is missing.
- No studies in people. Every cannabinoid result comes from animals or lab tissue, and the researchers write that clinical trials are needed before anything applies to patients [12][1].
- Mostly male animals. Several studies used only male rats or mice, so effects in females are unknown [12][13][5].
- Only the first hours and days. Protection was measured within 72 hours at most, and long-term recovery of function was not followed [12][1].
- One model per study. Each lab used a single way of causing ischemia, and one looked only at the frontal cortex, which may not match a human stroke [13][5].
- Dish results not yet confirmed in animals. The brain-slice findings for CBD and THC still need testing in living animals and then in people [8][9].
- Nothing on chronic small vessel disease. All the models copy sudden ischemia. No study addressed the slow form that many readers of this page live with.
- The one human study read records, not treatment. Hospital codes can misclassify, substance-related diagnoses are under-reported, and the results are associations, not causes [7].
Until trials in people exist, the honest summary is short: interesting in animals, unknown in patients, and in the case of THC during acute ischemia, possibly harmful [9].
Who should not use cannabis for this
For some people the answer is “not now” or “not at all,” whatever the symptom. Research in this field has not included them, so there is no evidence of safety for them.
- The acute period of a stroke or TIA, the days and weeks while treatment and tests are still under way. The only ischemia-specific signal for THC is harm in lab tissue [9].
- New or worsening symptoms that have not been checked. Call 911 for anything sudden; see the warning signs.
- Unstable or very high blood pressure that is not yet under control.
- Heart rhythm problems, including atrial fibrillation that is not well controlled.
- A history of psychosis; THC can bring it back. See cannabis and psychosis.
- Frequent falls in recent months, especially while taking a blood thinner.
- Pregnancy or breastfeeding. THC passes to the baby, and newborn brain injury from low oxygen has its own risk factors, shown below.
What raised the risk of newborn brain injury from low oxygen in California births?
Each row compares babies whose mothers had one condition with babies whose mothers did not. The dot is the best estimate of how much more often the injury occurred; the line is the likely range. Marks to the right of the gray “No difference” line mean more often. “Substance-related diagnosis” covers every substance recorded in hospital charts, not only cannabis, and the study shows links, not causes [7].
● estimate · ━ likely range (confidence interval) · │ no difference
-
Babies treated with cooling therapy
-
Babies not treated with cooling therapy
- Mother had diabetes before pregnancy 2.42× more often (2.02-2.91) [7]
Show as a table
| Condition in the mother | Group | aRR (95% CI) |
|---|---|---|
| Any infection | With cooling therapy | 2.33 (2.07-2.63) |
| Preeclampsia | With cooling therapy | 2.48 (2.07-2.97) |
| Substance-related diagnosis | With cooling therapy | 2.63 (1.96-3.53) |
| Preexisting diabetes | With cooling therapy | 2.11 (1.49-2.98) |
| Preexisting diabetes | Without cooling therapy | 2.42 (2.02-2.91) |
Talk to a licensed physician about whether any of these apply
Can I get a medical marijuana card for brain ischemia?
It depends on your state. Every medical cannabis program keeps its own list of qualifying conditions, and a physician has to match a diagnosis in your records to that list, not a symptom. Few programs name brain ischemia or stroke outright. Many cover conditions that often come with it, such as chronic pain, muscle spasms or seizures, and some let a physician certify any condition they judge debilitating.
The lists change as legislatures and health departments update them, so the current wording for your state is the one that counts. The physician confirms it at the evaluation, using your records, and weighs your medicines and blood pressure before recommending anything.
Brain ischemia or stroke is named
The simplest case. Bring the scan report or discharge summary that records the diagnosis, and the physician evaluates you against that listed condition.
A condition you also have is listed
Post-stroke pain, spasticity or seizures may be on the list even where ischemia is not. What counts is a diagnosis in your records.
Neither is on the list
A card may not be available yet where you live. Some states accept petitions to add conditions or allow other debilitating ones.
What else has a doctor diagnosed?
State lists name diagnoses, not symptoms. Pick what is in your records.
Choose a diagnosis above to see how it fits state lists.
Chronic pain: the most widely listed condition across state programs, and pain after a stroke is common. Read chronic pain and medical cannabis.
Muscle spasms: stiffness and spasms on the weak side after a stroke (spasticity) are covered by many programs. Read muscle spasms and medical cannabis.
Seizures: seizure disorders are on most lists, and they can follow a stroke; note the seizure-medicine interaction above. Read seizures and medical cannabis.
Headaches: some programs list migraine or chronic headache. Read headache and medical cannabis.
Depression: fewer states list it, though low mood after a stroke is common, and THC can affect mood in both directions. Read depression and medical cannabis.
None of these: then the decision rests on your state’s wording and the physician’s judgment. Start with your state’s medical marijuana laws.
Medical card or recreational purchase
In states with adult-use sales, adults can buy without a card. A card still changes several things, though the details are set state by state.
| Aspect | With a medical card | Recreational |
|---|---|---|
| Taxes | Often lower; some states waive part of the cannabis tax for patients | Full state and local cannabis taxes |
| Purchase and possession limits | Often higher; set by your state | Set for adult-use buyers |
| Products | Medical dispensaries and, in some states, medical-only products | Adult-use product range |
| Home growing | Allowed for patients in some states, with plant limits | Allowed in some adult-use states, with their own limits |
| Age | Patient age rules set by each program | Adult-use age limit set by the state |
| Physician involvement | A licensed physician reviews your conditions and medicines | None |
| Document | State card or recommendation, recorded in a confidential registry | Government ID only |
Will a card save you money?
It can, but only where your state taxes patients less than recreational buyers, and the amount depends on your state’s tax rates and how much you buy. Weigh that against the evaluation fee and any state registration fee. The breakdown is in medical vs. recreational cannabis taxes, and the wider differences in medical and recreational cannabis compared.
What the program in your state involves
Qualifying is the first of two steps. In most states a physician’s recommendation is followed by registration with the state health department, which issues the card and enters you in a confidential patient registry; in a few, the recommendation itself is what a dispensary asks for. Purchases happen at licensed dispensaries, some of which deliver, and their products are lab-tested and labeled with THC and CBD content, which matters here, given the THC findings above.
Many state laws also let a patient name a registered caregiver who may buy and handle products on their behalf, which can matter after a stroke that limits mobility; who qualifies and how to register is set by each state. Cards from one state are not automatically valid in another; see which states accept out-of-state cards. Possession limits, home growing and taxes are listed state by state on the laws and regulations pages.
Your rights with a medical card
A card protects you under your state’s law, not federal law, and the two differ in ways worth knowing before you apply.
- Privacy: your medical records are protected under the HIPAA Privacy Rule [23], and state patient registries are confidential; dispensaries and police can usually check only whether a card is valid.
- Firearms: federal law bars anyone who is an “unlawful user” of a controlled substance from having a firearm [24], and cannabis remains federally controlled, so a state card does not change the federal rule.
- Work: protections for card holders differ by state, and many employers can still enforce drug-free policies, especially in safety-sensitive jobs.
- Driving and travel: driving impaired is illegal everywhere, card or not, and carrying cannabis across state lines or onto federal land is not covered. Read traveling with cannabis before a trip.
What this means if you are considering it
A useful evaluation is a conversation about one or two specific problems, such as pain, spasms or sleep after a stroke, the medicines you already take and what would count as “better.” It is not a conversation about repairing the brain, because no cannabis product has been shown to do that. It goes faster and safer when the facts are on the table.
What to bring to the appointment
Tap each item as you get it ready.
Questions worth asking
- Could anything I take, especially my blood thinner or antiplatelet, interact with cannabis, and what would we watch for?
- Given the lab findings on THC, should a product be CBD-only or low in THC, and why?
- How long after my stroke or TIA should I wait before trying anything new?
- How would we know within a few weeks whether it is helping the symptom we chose?
- What should make me stop right away, and whom do I call?
An evaluation makes sense if
- A specific symptom, such as pain or spasticity, has not settled with the usual steps.
- Your stroke prevention is in place and your blood pressure is controlled.
- Your full medicine list can be reviewed.
- Your state’s program covers your diagnosis or a related one.
It is not the right step if
- The hope is to reverse brain damage or prevent a stroke.
- Symptoms are new and have not been checked.
- There have been recent falls on a blood thinner.
- There is a history of psychosis, or a pregnancy.
This page summarizes published research for education. It does not replace a physician’s advice. Cannabis does not treat or reverse brain ischemia, and the research behind this page was done in animals and lab tissue, not in patients.
How to get a medical marijuana card online
Everything happens online, so there is nowhere to travel, which matters when driving is off the table after a stroke. Four steps take you from the first form to a card in your hand.
Fill in the intake form
Your state, your diagnoses and your current medicines. Have the scan report or discharge summary ready to upload.
See a physician licensed in your state
A one-on-one appointment online. You agree on the time with the physician; keep an hour free rather than a minute.
Receive your signed recommendation
If the physician approves, the signed recommendation arrives in your account.
Register with your state
Where required, you submit the recommendation to the state program, which reviews it and issues the card.
Where are you starting from?
Renewing your card
Cards expire on a schedule your state sets. Renewal is a repeat evaluation with your updated medicine list and any new scans or diagnoses since last time, followed by the state’s own renewal step where one is required. Start before the expiry date so there is no gap, and bring anything that changed: a new blood thinner, a new event, a new specialist’s note. Choose your state from the list at the top of this page for its renewal path, and find past recommendations in your account and documents.
What you end up with
Across 250 reviews from patients in the states where we are licensed. We do not sort them by score and do not hide the low ones.
- 150,000+patients evaluated – everyone who has been through an appointment with us, in every state where we are licensed
- Since 2017doing only this: online evaluations for medical cannabis programs, and nothing else on the side
A recommendation from a physician licensed where you live, and, once your state registers it, a card that lets you buy at licensed dispensaries. Your documents stay in your account and documents, and how the medical card works explains the evaluation in detail. The physicians who see patients are listed on our physicians page.
Programs for veterans and for people with low income are available in some states.
Frequently asked questions about brain ischemia and cannabis
Is brain ischemia the same as a stroke?
Not exactly. Brain ischemia is the shortage of blood flow itself. If it clears within minutes without lasting damage, it is a transient ischemic attack; if it lasts long enough to kill brain tissue, it is an ischemic stroke. Chronic ischemia is a slower, quieter form seen on scans. Any sudden symptom is treated as a stroke: call 911.
How long can you live with brain ischemia?
Many people with mild chronic ischemic changes live a normal life span, especially when blood pressure, cholesterol, diabetes and smoking are dealt with. After a stroke, outlook depends on its size and location, your age and how fast treatment began. The research on this page reports no survival figures, so your neurologist is the right person to ask.
Can brain ischemia be reversed?
Partly. Tissue around a fresh stroke can be saved if blood flow returns within hours, and TIA symptoms resolve completely. Tissue that has died does not grow back, but rehabilitation helps healthy areas take over. Chronic changes are slowed, not erased, by treating their causes. No medicine reverses the damage, cannabis included.
Is brain ischemia hereditary?
Partly. A family history of early stroke raises your risk, and some inherited conditions affect clotting or the small vessels. For most people, though, the main drivers are ones you can act on: blood pressure, diabetes, cholesterol, smoking and atrial fibrillation. Tell your doctor about any relative who had a stroke young.
Does CBD help brain ischemia?
Not in people, as far as anyone knows. CBD reduced damage in rat brain slices and in mice with an induced stroke [9][5], but no study has tested it in patients. CBD also affects liver enzymes that clear many medicines, so it is not automatically harmless alongside blood thinners. Show your physician the product and your medicine list.
Is cannabis safe with blood thinners after a stroke?
There is no safety data for that combination. Cannabinoids share liver enzymes with warfarin and some newer blood thinners, THC can cause dizziness and falls, and a fall on a blood thinner can mean bleeding. Never stop or change a blood thinner to try cannabis; review any product with the doctor who prescribes it. Details are in the safety section.
Does brain ischemia qualify for a medical marijuana card?
It depends on your state’s list. Few programs name it directly, but many cover conditions that often come with it, such as chronic pain, muscle spasms or seizures, and some allow other debilitating conditions. A physician matches the diagnosis in your records to your state’s current list. See who qualifies and your state’s rules.
What about delta-8 THC or hemp CBD products sold without a card?
Hemp-derived products sold in shops and online are often less tightly regulated than dispensary products, and labels may not match what is inside. Delta-8 THC acts much like regular THC, with the same dizziness, blood pressure and interaction concerns. Given the lab findings on THC in ischemia, an unlabeled product is the hardest one to judge.
Can I use my card in another state?
Sometimes. Reciprocity, one state honoring another state’s card, exists in some states and not others, and rules for visitors vary. Check which states accept out-of-state cards and traveling with cannabis before a trip.
What if my card is lost?
Most states let you request a replacement from the program that issued it. The steps are in what to do if your card is lost and the medical card FAQ, and your recommendation stays in your account and documents.
How do I renew my medical card?
Cards expire on a schedule your state sets, and renewal means a repeat evaluation with your updated medicines and a new recommendation. Bring any new scans, events or prescriptions since last time. Choose your state from the list at the top of this page for its renewal path, or read how the online process works.
How much does it cost, and what if I’m not approved?
The evaluation fee for your state, and anything else that applies to it, is shown before you pay; a state registration fee, where one exists, is paid to the state separately. Whether a recommendation is issued is the physician’s medical decision, and the terms for your state, including what happens to your payment if you are not approved, are on how the medical card works.
Is an online evaluation legitimate?
Yes, where state law allows telemedicine for medical cannabis evaluations. The appointment is with a physician licensed in your state, one-on-one, and the recommendation is the same document an in-person visit would produce. For many people after a stroke, not having to travel is the deciding point.
Who finds out? Privacy, firearms and work
Your medical records are protected under the HIPAA Privacy Rule [23], and state registries are confidential. Federal law bars “unlawful users” of controlled substances from owning firearms [24], and a state card does not change that. Workplace protections differ by state. The details are in your rights with a medical card.
More research on cannabis and brain ischemia
This page cites a selection of studies. Our research library holds every study we track on cannabis and brain ischemia, from laboratory work to clinical trials, and lets you filter them by cannabinoid, study type and year.
- studies
- 84
- in people
- 53
- clinical trials
- 1
Related brain and nervous system conditions
Brain ischemia often travels with other diagnoses, and some of them appear on more state lists. Each page below covers its own research and qualifying rules.
Background reading and latest news
For how cannabis works in the body, and for new articles as research and laws change:
References
24 sources
- 1. Cannabinoid CB1 receptor agonist ACEA alleviates brain ischemia/reperfusion injury via CB1-Drp1 pathway. DOI: 10.1038/s41420-020-00338-3 PMID: 33083022
- 2. American Stroke Association. Stroke Symptoms. 2024.
- 3. National Institute of Neurological Disorders and Stroke. Stroke. 2024.
- 4. Centers for Disease Control and Prevention. Signs and Symptoms of Stroke. 2024.
- 5. Effects of Cannabidiol and Beta-Caryophyllene Alone or in Combination in a Mouse Model of Permanent Ischemia. DOI: 10.3390/ijms22062866 PMID: 33799861
- 6. CDC National Center for Health Statistics. ICD-10-CM: International Classification of Diseases, Tenth Revision, Clinical Modification. 2026.
- 7. Risk factors for neonatal encephalopathy in late preterm and term singleton births in a large California birth cohort. DOI: 10.1038/s41372-021-01242-z PMID: 34702969
- 8. The Protective Effect of CBD in a Model of In Vitro Ischemia May Be Mediated by Agonism on TRPV2 Channel and Microglia Activation. DOI: 10.3390/ijms232012144 PMID: 36292998
- 9. Neuroprotective Effects of Cannabidiol but Not Δ9-Tetrahydrocannabinol in Rat Hippocampal Slices Exposed to Oxygen-Glucose Deprivation: Studies with Cannabis Extracts and Selected Cannabinoids. DOI: 10.3390/ijms22189773 PMID: 34575932
- 10. Role of 2-Arachidonoyl-Glycerol and CB1 Receptors in Orexin-A-Mediated Prevention of Oxygen-Glucose Deprivation-Induced Neuronal Injury. DOI: 10.3390/cells9061507 PMID: 32575773
- 11. Endocannabinoids modulate human blood-brain barrier permeability in vitro. DOI: 10.1111/bph.13106 PMID: 25651941
- 12. Propofol Attenuates Brain Ischemic Injury Through the Cannabinoid Type 1 (CB1) Receptor. DOI: 10.7759/cureus.106641 PMID: 42110069
- 13. Kaempferol Regulates Lipid Homeostasis, Endocannabinoid System, and PPARα in Rat Cerebral Cortex Following BCCAO/R. DOI: 10.3390/biom15101440 PMID: 41154667
- 14. The Neuroprotective Effects of mGlu1 Receptor Antagonists Are Mediated by an Enhancement of GABAergic Synaptic Transmission via a Presynaptic CB1 Receptor Mechanism. DOI: 10.3390/cells11193015 PMID: 36230976
- 15. Involvement of the endocannabinoid system in the physiological response to transient common carotid artery occlusion and reperfusion. DOI: 10.1186/s12944-016-0389-y PMID: 28103941
- 16. Alteration of SLP2-like immunolabeling in mitochondria signifies early cellular damage in developing and adult mouse brain. DOI: 10.1111/ejn.13124 PMID: 26547131
- 17. Mitochondrial CB1 receptor is involved in ACEA-induced protective effects on neurons and mitochondrial functions. DOI: 10.1038/srep12440 PMID: 26215450
- 18. Involvement of GluR2 up-regulation in neuroprotection by electroacupuncture pretreatment via cannabinoid CB1 receptor in mice. DOI: 10.1038/srep09490 PMID: 25830356
- 19. Effect of acute administration of Pistacia lentiscus L. essential oil on rat cerebral cortex following transient bilateral common carotid artery occlusion. DOI: 10.1186/1476-511X-11-8 PMID: 22239952
- 20. Tetrahydrocurcumin ameliorates homocysteinylated cytochrome-c mediated autophagy in hyperhomocysteinemia mice after cerebral ischemia. DOI: 10.1007/s12031-011-9695-z PMID: 22212488
- 21. CB2 receptor activation attenuates microcirculatory dysfunction during cerebral ischemic/reperfusion injury. DOI: 10.1016/j.mvr.2009.03.005 PMID: 19332079
- 22. U.S. Food and Drug Administration. FDA Regulation of Cannabis and Cannabis-Derived Products, Including Cannabidiol (CBD). 2024.
- 23. U.S. Department of Health and Human Services. The HIPAA Privacy Rule. 2024.
- 24. Legal Information Institute, Cornell Law School. 18 U.S. Code § 922: Unlawful acts. 2024.