The Ultimate Guide to

CBD

CBD (Cannabidiol), is one of two highly researched cannabinoids extracted from cannabis. The other is THC. While they both promote health and healing, CBD produces none of the psychedelic-like effects of THC.

Primarily extracted from industrial hemp (which is often legal where cannabis is not), CBD now has mainstream appeal. People use CBD for anxiety, depression, arthritis, cancer, and many other conditions. As to the validity of these uses, clinical research is ongoing. But CBD has already been approved as a life-changing treatment for seizures.

Most CBD users take it as an oil, in capsules, or by vaping. But you can also get CBD edibles, CBD energy drinks, CBD topical balms, CBD massage oils, and so on. Although so-called full-spectrum CBD products (containing THC and other cannabis-derived compounds) are available where cannabis has been legalized, most countries and jurisdictions only allow the use of CBD isolate or broad-spectrum products (with a maximum of 0.2-0.3% THC).

Brief history

Hemp is one of the oldest agricultural crops, having been in continuous use in Europe and Asia for at least 10,000 years.^[1] Evidence also suggests that as many as 30,000 years ago it was harvested from the wild for rope.^[2]

The ancient Chinese may have been the first to use it medicinally. According to their “classic of herbal medicine,” the Shennong Bencaojing, it helped with more than 100 conditions. And they also used hemp to make paper.^[2][3][4]

Centuries later, the plant became a staple of industry—especially for the production of textiles. European colonists relied on hemp for unparalleled rope and sail cloth. It was grown by the Spanish in South America and by the British in their colonies in the North—first in Canada and Virginia, then in other fledgling states. In fact, hemp was so important to the founding fathers that farmers were forced to grow it on their land.^[4][5][6] Nowadays, of course, they need a license.

The demonization of hemp as “marijuana” began in the 20th century. Prohibitionists used the Mexican term to play on fears of an immigrant menace. They also linked cannabis to blacks. In 1937, the Marihuana [sic] Tax Act undermined hemp’s viability as a cash crop and levied fines on unregulated use.^[5][7]

It wasn’t all about racism, though; the other motivation was greed. As Jack Herer pointed out in the 1980s, those who led the charge against cannabis had investments that were threatened by hemp.

The US Treasury Secretary Andrew Mellon, for instance, the man who appointed Harry Anslinger to draft the tax act (and whose niece was Anslinger’s wife), had sunk a fortune into nylon and rayon. These synthetic fibers from conglomerate DuPont were in every way inferior to hemp.^[5]

And, to the dismay of Big Oil and Steel, Henry Ford produced a bio-plastic car—not only made from American farm crops (hemp, soy, corn, etc.) but fueled by hemp oil as well. It was 300 pounds lighter than steel and capable of withstanding an ax blow. It was mostly renewable too.^[8]

Some say there was a war of ideas: The hydrocarbon-based society (“the Rockefellers and the Hearsts with oil and petroleum”) on the one hand and the carbohydrate-based society (“Henry Ford with his biological economy”) on the other. Hemp, the “plant of 50,000 uses,” the fast-growing “crop of the future,” ultimately fell by the wayside.^[6]

What’s absolutely clear is that prohibition lacked scientific support. As far as the medical community was concerned, it was never a public health issue. Not only did Anslinger ignore their advice not to ban it,^[5] but he once called his own claim that cannabis causes violence “absurd.”^[7]

In spite of the politicking, scientists continued to research the plant. Within a few years they isolated CBD (Roger Adams, 1940).^[9] And later, they established its structure (Raphael Mechoulam, 1963).^[10]

In 1969, psychologist and psychedelic pioneer Timothy Leary got the Marihuana Tax Act overturned.^[11] But it didn’t really make any difference. Congress had already approved participation in the UN Single Convention on Narcotic Drugs and, the following year, President Richard Nixon signed the Controlled Substances Act into law—listing cannabis and its derivatives under Schedule I.^[12]

The reintroduction of medical marijuana has been a long and complicated process. For more on prohibition and legalization, see our Essential Guide to Cannabis.

But, for CBD at least, perhaps the watershed moment came in 2013 when the public learned of 6-year-old Charlotte Figi. Featured in the CNN documentary Weed, the Dravet syndrome patient was said to have 300 seizures a week. And conventional medications didn’t help. Only when her parents gave her CBD oil did she experience lasting relief. She started walking, talking, sleeping better, and eating without the aid of a feeding tube. Her seizures were down to a manageable 2-3 a month.^[13]

The story prompted CNN’s chief medical correspondent Sanjay Gupta to apologize for his role in “terribly and systematically” misleading the public as to the “dangers” of cannabis use.^[14] It also catalyzed long-overdue policy change at the state and federal levels, along with urgent clinical research.

The FDA approved Epidiolex-branded cannabidiol in 2018 for Dravet and Lennox-Gastaut syndromes. And the DEA listed this “new” treatment under Schedule V of the Controlled Substances Act (“low potential for abuse”; “accepted medical use”). However, CBD per se remained illegal (Schedule I: “high potential for abuse”; “no currently accepted medical use”).

For a little while, anyway. That December, Congress passed the Agriculture Improvement Act (aka Farm Bill) of 2018 with enthusiastically bipartisan support. Seeking to revitalize America’s hemp industry, the Farm Bill legalized CBD.^[15][6]

Current use

Demand for CBD is high and continuing to grow. According to cannabis industry analysts Brightfield Group, the CBD market will be worth $22 billion by 2022.^[16]

In 2017, they counted more than 1,200 brands. Among the most popular were Care By Design, Bloom Farms, Kiva Confections, and CW/Charlotte’s Web. But there’s a high level of satisfaction all round, with 90% of Brightfield’s survey respondents saying they’d buy CBD products again.

In fact, according to the same survey, most who use CBD medicinally find it more effective than other medications. And 80% of all users take CBD at least once a week; most of them take it every day.

As for demographics, the majority of CBD users appear to be evenly distributed between the ages of 26 and 64—and apparently they tend to be white.^[17]

CBD is one of more than a hundred cannabinoids found in cannabis.^[18] These are terpenophenolic compounds (a mixture of terpenoids and phenols) that among other things protect the plant against parasites.^[19] Some of the most common cannabinoids besides CBD are THC (delta-9-tetrahydrocannabinol), CBC (cannabichromene), CBN (cannabinol), CBG (cannabigerol), and THCV/THV (tetrahydrocannabivarin).

CBD is actually a structural isomer of THC, which means it has the same atoms but in a different configuration. Whereas the THC molecule has a planar (i.e. flat) configuration of atoms, the CBD molecule is “bent” with two rings at right angles to each other. This is thought to explain some of its different effects.^[20]

Receptor binding

Unlike THC, CBD has low affinity for the cannabinoid (CB) receptors. However, it does appear to antagonize (interfere with or inhibit) a number of CB agonists (activators)—including THC.^[20][21][23]

CBD effects are instead primarily attributed to the serotonin (5-HT) system. Its agonism of 5-HT1A receptors in particular is widely (though not universally) thought to explain its antidepressant and anxiolytic effects.^[23]
[24] CBD has also been found to inhibit the degradation of tryptophan, the amino acid precursor to serotonin.^[23]

As a possible adenosine uptake inhibitor, CBD may increase levels of adenosine. This is thought to explain its anti-inflammatory and neuroprotective effects, as well as its mitigation of trauma-related psychiatric disorders.^[23]
[25]

CBD also binds to ion channels such as the TRPV1 receptors, activating them to mediate pain, inflammation, and temperature. Meanwhile, its antagonism of GPR55 receptors modulates blood pressure and bone density—an effect that’s of interest for cancer treatment. By inhibiting the enzyme FAAH, CBD also slows the breakdown of anandamide and other endocannabinoids, leading to increased levels of these in the brain.^{[21]
[23][26][27][28][29][30]}

Furthermore, CBD interacts with the mu- and delta- opioid receptors, showing promise for the treatment of addiction.^[23][31] See Therapeutic Use for more on medicinal applications.

Other reported targets include the GABA, PPARγ, glycine, acetylcholine, and dopamine systems.^{[23][24][21][33]} There’s still much to learn about this cannabinoid’s complex pharmacology.

Safety and toxicity

Research into the safety of high-dose, pure CBD is ongoing, but there appears to be no cause for concern.

A 2011 review of more than 130 studies, for example, found that even chronic high doses of up to 1,500 mg per day are well tolerated—at least by some people.^[34] Another review, published in 2016, concluded that chronic long-term use is likely to be generally safe.^[35] And while an online survey found that as many as one in three people may experience side effects, these tend to be mild or even desirable. Some of the most common CBD side effects, for instance, include:^[36]

• Euphoria
• Increased appetite
• Sleepiness
• Dry mouth
• Red eyes

Because CBD is often given to children, though, there are concerns about its impact on brain development. This is an area that may warrant further research—especially when it comes to unregulated, possibly contaminated products. That said, there is some indication (in vitro) that CBD has no effect on embryonic/fetal development and its neuroprotective effects are well documented.^[34][37]

As for a lethal dose, there are no human fatalities on record. Rhesus monkeys given 200 mg/kg (intravenous) died from respiratory and cardiac failure,^[34] but this dose was obviously extreme. For the average human it would be the equivalent of 12.4 grams (124 x 100 mg bottles) of CBD. Intravenous administration is rare anyway. Common methods don’t produce anywhere near the same blood concentration.

Still, CBD might not be suitable for all. Some may experience allergic reactions, either from added ingredients (e.g. propylene glycol in CBD e liquid) or from CBD itself.^[38] CBD (or Epidiolex, specifically) has also been linked to liver problems. Symptoms may include:

• Loss of appetite
• Nausea, vomiting
• Fever
• Lethargy
• Itching
• Jaundice
• Dark urine
• Stomach pain or discomfort

If you experience any of these symptoms, you may need to adjust your dose or stop taking CBD entirely. If you’re taking CBD for seizures, however, you may need to taper off gradually. If in doubt, talk to your doctor.^[39]

Drug interactions

CBD can affect the way other medicines work.^[34][35] For example, it may inhibit the breakdown of the widely prescribed blood thinner warfarin (e.g. Coumadin), potentially leading to bleeding. The potency of the antiepileptic drug clobazam (e.g. Onfi, Sympazan) may also be increased.^[40]

CBD apparently interferes with the metabolism of these drugs via modulation of the cytochrome P450 (CYP) class of enzymes. So it’s advisable to find out which enzymes metabolize whatever medications you’re on, and how they’ll be affected by CBD.^[40][41]

Some other potential interactions include:

• Amiodarone, erythromycin, fluconazole, verapamil: Can increase CBD concentration
• Rifampicin: Can decrease CBD concentration
• Diflunisal, propofol, fenofibrate, gemfibrozil, lamotrigine, morphine, lorazepam, montelukast, phenytoin: Concentration can be increased by CBD
• Theophylline, caffeine, bupropion, efavirenz: Concentration can be increased or decreased by CBD^[42]

Interactions are more common when CBD and another drug are taken orally. But they’re not necessarily a major risk factor; this information is really just to make you aware. CBD is generally well tolerated with other drugs.^[41][43]

CBD dosage

The most common routes of administration are oral (e.g. capsules, oils, sublingual tinctures) and inhaled (e.g. vapes).^[17][44] CBD can also be taken intranasally as a spray or topically/transdermally as a cream or patch.

Figuring out a dosage can be tricky, but CBD Origin has a guide and calculator to help. As a general rule, they suggest 1-6 mg CBD for every 10 pounds of body weight—starting out small and gradually increasing your dose.

To work out how much CBD, approximately, is in each dropper’s worth or each puff of your vape:

• Divide the total amount (mg) of CBD in your bottle by the number of milliliters in your dropper/vape cartridge (usually 1 ml); this is your dropper dose
• To work out your puff dose, divide by how many puffs you get from a cartridge (usually 100-200)^[45]

Vaping CBD

CBD liquids and concentrates for vaporizing provide an accessible way to take controlled, potent doses, without needing to smoke or digest the substance to feel any effects.

Whether you are interested in vaping CBD juice as a calming replacement for smoking or using a high potency concentrate cartridge for chronic pain, there are plenty of available options on the CBD vaporizer market. Be sure to research CBD laws in your particular area, and look into the standards and processes behind whatever CBD product you are eyeing.

Bioavailability

CBD capsules have among the lowest bioavailability due to the way they’re metabolized. Broken down by the stomach and liver, only 4-20% of your dose will be active. In other words, a 100 mg capsule may deliver just 4 mg CBD.^[46]

Sublingual administration enters the bloodstream more directly, with reported bioavailability of 12-35%. But vaping is even more direct, apparently delivering 34-46% via the lungs.^[46]

However, it’s important to note that dosage guidelines probably aren’t adjusted for bioavailability. So if someone recommends 100 mg CBD ingested, don’t assume they mean after metabolism and take 500-2,500 mg!

What to expect

Effects may be felt within 30-90 minutes of a single dose and are said to last 4 hours or more.^[47][48]

People generally report feeling more relaxed and mindful. Sufferers of anxiety, in particular, notice a fundamental shift in their stress levels.^[48][49][50] Those using CBD oil for pain and other specific symptoms generally notice improvement, if not within the first 90 minutes then with sustained use or a gradually titrated dose.

The effects of CBD are often compared favorably with those of cannabis but without any paranoia or social inhibition. Alertness and focus may also be increased. And mood enhancement is common.^{[49][50][51][52]}

“Non-psychoactive” is a label commonly applied to CBD, but a more accurate description would be “non-psychotomimetic” or “non-psychedelic.” It doesn’t produce the characteristic perceptual changes of THC. In other words, you can take it and carry on with your day.

Precautions

That said, drowsiness is possible so potentially dangerous activities such as driving or operating heavy machinery should probably be avoided—at least until you know how CBD affects you.^[39][48]

It’s also important to monitor for side effects such as nausea and diarrhea, particularly as you increase the dose.^[53] You may have an adverse reaction to certain carrier oils and other ingredients, such as propylene glycol in CBD vape liquid, or to CBD itself.^[54] However, as previously mentioned, it might not be safe to stop using CBD without gradually tapering off. It depends on your reasons for taking it. If in doubt, talk to your doctor.

“CBD is medicinal and THC is recreational”

To some extent this is true; CBD tends to be used medicinally, whereas THC tends to be used for its distinctive psychoactive effects.

However, both CBD and THC are medicinal in their own ways. In fact, medical marijuana and THC-based medications were approved long before Epidiolex. And THC can actually potentiate CBD for the treatment of certain conditions.

As Project CBD points out,^[55] framing one as medicinal and the other as “recreational” based solely on psychoactive effects is not only wrong; it’s also straight out of the prohibitionist’s playbook. Cannabis isn’t just medicinal in spite of its psychoactive effects but, like many psychedelics, precisely because of them as well.

“CBD converts into THC in the stomach and gets you high”

This relatively persistent myth may have something to do with Raphael Mechoulam’s conversion of CBD to THC in the lab. In the human body, CBD produces only trace amounts of THC—certainly not enough to get you stoned.

As recently as 2016, however, a team of researchers claimed otherwise. Published in Cannabis and Cannabinoid Research, their paper wildly overstated the conversion and linked oral CBD to “poor motor and cognitive performance.”

Their findings have been roundly debunked, and the researchers themselves have been discredited. Unsurprisingly, they were funded by Zynerba Pharmaceuticals, a company that, just days later, announced plans for transdermal CBD. This, they claimed, would bypass the THC problem—a problem they’d effectively made up.^[56]

CBD isolate is not to be confused with medical marijuana, or with dronabinol (Marinol), nabilone (Cesamet), or nabiximols (Sativex). Each of these contains THC and is psychoactive to some extent.

Because psychoactivity is widely considered an adverse side effect in the development of new medications, CBD appeals to pharmaceutical researchers. However, CBD isolates may lack the synergistic “entourage effect” of full-spectrum CBD products containing THC and other phytocannabinoids.^[57][80]

Even so, pure CBD is an extraordinarily promising therapeutic agent. Its properties include:

• Anxiolytic^{[20][23][24][35][57][58]}
• Antidepressant^{[35][57][59][60][61][62][63]}
• Anti-inflammatory (e.g. for inflammation-related neurodegeneration)^[24][35][58]
• Antiasthmatic^[44]
• Antineoplastic (antitumor)^{[24][33][35][58][65][66][67]}
• Antiemetic or antinausea^[24][58]
• Antipsychotic (without adverse side effects like weight gain)^{[24][34][35][57]}
• Antioxidant (e.g. for oxidative neurological disorders and skin conditions like acne)^{[24][35][57][58]}
• Anticonvulsant^{[24][33][35][42][68]}
• Antiarthritic^[24][35][58]
• Analgesic (e.g. for neuropathic pain)^[24]
• Neuroprotective (e.g. for depression, stroke, and neurodegenerative diseases)^[57]
• Neuroplastic (e.g. for mood disorders, PTSD, schizophrenia, and neurodegenerative disease)^[25][57][69]

Here are some promising CBD medical applications by condition:

Epilepsy

CBD significantly reduces seizure frequency, even in patients with otherwise treatment-resistant epilepsy (e.g. Dravet and Lennox-Gastaut syndromes).^[35][42] One study reported an average reduction of 45% over three months of treatment.^[35] Side effects, including tiredness and diarrhea, tend to be mild, infrequent, and relatively uncommon.^[68]

CBD also appears to be well tolerated over the long term—over a period of at least 144 weeks, according to one study.^[68]

Schizophrenia

Antipsychotic medications are often associated with adverse side effects such as weight gain. CBD, on the other hand, produces fewer side effects (if any) and appears to be as effective as amisulpride.^[34][35][57]

Doses are relatively high for schizophrenia, though, with gradual increases to more than 1,000 mg/day being common.^[34]

Depression

CBD appears to inhibit the reuptake of the endocannabinoid anandamide (AEA), similar to how SSRI antidepressants inhibit the reuptake of serotonin.^[62] In other words, it may increase AEA levels in the brain. It also appears to enhance serotonin neurotransmission.^[61]

Unlike conventional antidepressants, though, CBD may provide rapid relief. This has been linked to glutamatergic neurotransmission and BDNF-mediated signalling, similar to ketamine. Neuroplasticity and neurogenesis may also account for CBD’s sustained antidepressant effect.^{[57][59][62][63]}

Anxiety

CBD appears to be optimally anxiolytic at moderate doses (300-600 mg). It’s actually thought to be as effective as diazepam (e.g. Valium), but without the safety concerns.^[24]

Anecdotal reports widely support the use of CBD oil for anxiety.

PTSD

The endocannabinoid system is thought to be involved in emotional memory processing.^[70][71][20] And while CBD has low affinity for the cannabinoid receptors, it appears to increase AEA by inhibiting its reuptake, as mentioned above.

This is interesting given that PTSD patients appear to have lower levels of AEA, along with higher levels of CB1 receptors presumably to compensate for the deficit. It’s well documented that PTSD sufferers are more likely to use cannabis, and this may be why.^[71]

The benefits of CBD, as opposed to CB1 agonist THC, for the treatment of PTSD, include its lack of anxiogenic side effects. It can also be used to interrupt the formation, retrieval, and reconsolidation of traumatic memories. Ultimately it could extinguish these memories altogether, while at the same time promoting neurogenesis.^[20][24][25]

Addiction

CBD appears to alleviate the withdrawal symptoms and cravings of (some) drug addiction.^{[23][34][35][72]} As with PTSD, this may have to do with memory processing and extinction.^[20]

In one study, heroin addicts given daily doses of CBD (either 400 or 800 mg) over three days were presented with opioid-related video cues one hour, twenty-four hours, and seven days later. Cravings were reduced even after seven days.^[35]

Evidence suggests CBD could also help cigarette smokers and alcoholics to quit without relapse.^[35][73] And while it doesn’t appear to alleviate cocaine cravings, it does address the primary triggers of cocaine relapse—namely stress and anxiety.^[74][69]

OCD

Limited evidence from animal studies suggests CBD might help with obsessive compulsions.^[24]

Parkinson’s disease

CBD can also alleviate psychotic symptoms in Parkinson’s disease patients, again without serious side effects.^[34][35] It also appears to improve quality of life generally, enhancing emotional wellbeing, cognition, and communication.^[35][75]

Alzheimer’s disease

Limited evidence suggests CBD may help with social recognition deficits in Alzheimer’s patients.^[35]

Stroke

The neuroprotective (perhaps antioxidative and anti-inflammatory) effects of CBD are of interest for the prevention and treatment of stroke.^[58][76]

Arthritis

CBD’s anti-inflammatory and immunosuppressive effects are thought to be anti-arthritic.^[35][58]

Cancer

Numerous anecdotal reports attribute cancer remission to CBD.^[77] There’s also a case report of an 81-year-old man diagnosed with lung cancer in October 2016 whose tumor significantly reduced in size by November the following year. Having turned down radiation and chemotherapy, the only change in his lifestyle had been self-administration of CBD: 1.32 mg twice daily for a week, then 6 mg twice daily for another week. And he only started in September 2017. (He stopped because the taste was unpleasant.)^[65]

Although numerous, such reports are hardly conclusive; they don’t prove that CBD kills cancer. In fact, it may adversely interfere with conventional cancer treatments.^[67] But CBD does appear to reduce tumor size and metastasis, even if we don’t yet know how.^[35][58][66] Various mechanisms have been proposed, including the regulation of intracellular Ca2+ via TRPV agonism and the potentiation of neutralizing antibodies.^[65]

Colitis and Crohn’s disease

Mounting evidence supports the use of CBD for treating colitis and inflammatory bowel disease, including Crohn’s.^[78][79]

Diabetes

Animal studies suggest CBD may help to prevent the onset of diabetes.^[58]

Migraine

CBD has been proposed as an alternative to intranasal capsaicin (basically, mild pepper spray) for the treatment of migraine.^[80]

Sleep disorders

CBD improves sleep quality in Parkinson’s patients, and has been shown to alleviate REM sleep behavior disorder (RBD, or the acting out of dreams).^[37][69] At high doses, CBD appears to be sedative without interfering with the sleep cycle.^[69]

Autism spectrum disorder (ASD)

CBD may help to alleviate symptoms of ASD, such as anxiety, depression, social avoidance, and poor quality sleep.^[37] It also reportedly helps autistic children to talk.^[81]

In one study, autistic children with severe behavioral problems were given cannabis extract containing CBD and THC at a ratio of 20:1. This was administered sublingually three times a day with the total dose increasing from 1 mg/kg/day to 10 mg/kg/day over a period of 2-4 weeks. Following treatment, 61% showed substantial improvements and 24% stopped taking other medications (e.g. antipsychotics), while 33% took less.^[82]

Fragile X syndrome

Daily doses of CBD (32-63.9 mg in three case reports) can also help with symptoms of fragile X syndrome, the leading genetic cause of autism. Improvements to sleep, feeding, motor coordination, language skills, sensory processing, sociability, and anxiety appear to be dependent on CBD.^[83]

Pets

Some people give CBD to their pets. As in humans, it’s said to help with anxiety, PTSD, arthritis, chronic pain, and other conditions.^[84] Although there is no FDA-/USDA-approved CBD oil for dogs, cats, and other pets, neither has the FDA received any negative reports (as of April 2, 2019).^[85]

Contraindications

It’s important to note that, for all its portrayal as a panacea, CBD could actually worsen some conditions. As an immunosuppressant, for instance, it could potentially exacerbate HIV.^[34] If in doubt, talk to your doctor.

Creativity

CBD can apparently stimulate a flow of ideas between otherwise seemingly distant concepts.^[86] Neurologists call this “hyper-priming” and link it to cannabis use in general.^[87] However, while THC also promotes creative thinking, the stoning effect can limit activity. CBD, on the other hand, facilitates the translation of ideas into works.^[88]

Relationships

Creativity, along with presence and mindfulness, can enhance relationships too.^[89] Some find CBD makes them more open and attentive to others—and to themselves. “I felt room to observe/attend to the source of various inner tensions,” said one CBD user, “free to enjoy the apparent assets of my person and character which are usually distorted under waves of self-criticism and doubt.”^[90]

Meditation

CBD can expedite meditative states, and some people use it for yoga. Of course, this may be missing some of the point of meditation/yoga as mental/physical discipline,^[91] but it’s apparently helpful for those starting out.

CBD has been shown to increase alertness and focus when taken in low doses. It isn’t a stimulant (caffeine is much more powerful and mind-altering than CBD), and you won’t get the jitters. It simply allows you to focus a little more, helping you keep your mind on your breath or your pose and not on what you are making for dinner that night.

Exercise

CBD reportedly helps with exercise in a number of ways—for example by increasing resistance to pain, promoting focus, and enhancing relaxation and sleep post-workout.^[92] It also helps to boost stamina and build muscle in various ways, such as by regulating hormones and blood sugar.^[93]

Endorsed by numerous athletes, CBD is a powerful performance enhancer. And it’s one the World Anti-Doping Agency doesn’t frown on.^[93]

The legality of CBD can be complex. Often it’s treated as a medicine (or supplement, food, cosmetic, etc.) and not as a “narcotic” or “psychoactive substance.” So even where cannabis is legal or decriminalized there may be restrictions on CBD.

Unless otherwise stated, this list applies only to CBD products derived from industrial hemp, i.e. cannabis containing no more than 0.2% THC (or 0.3% in the US).

Where is CBD legal?

The following information may not always reflect the latest developments, but we’ll endeavor to keep it up to date. It is only intended to cover the personal, non-medical possession and use of CBD.

Countries where CBD is legal

To the best of our knowledge, CBD is currently legal in:

• Argentina (with prescription)^[94]
• Austria (with prescription)^[94]
• Belgium (with prescription)^[94]
• Brazil (with prescription)^[94]
• Bulgaria^[94]
• Colombia (less than 1% THC)^[94][95]
• Croatia^[94]
• Cyprus^[94]
• Czech Republic (less than 0.3% THC)^[94]
• Estonia^[94]
• Finland (with prescription)^[94]
• France (0% THC)^[94]
• Germany (with prescription)^[94]
• Greece^[94]
• Hungary^[94]
• Italy (up to 0.6% THC)^[94]
• Latvia^[94]
• Lithuania^[94]
• Luxembourg (up to 0.3% THC)^[94]
• Malta (with prescription)^[94]
• Mexico (less than 1% THC)^[94]
• New Zealand (with prescription)^[94][96]
• Norway (0% THC)^[94]
• Paraguay (with prescription)^[94]
• Peru^[94]
• Poland^[94]
• Portugal (with prescription)^[94]
• Romania^[94]
• Slovenia^[94]
• Sweden (0% THC)^[94]
• Switzerland (less than 1% THC)^[94]
• Ukraine (0% THC)^[94]
• United Kingdom (0% THC; otherwise with prescription)^{[94][97][102]}
• United States (specifics vary by state)^[94][98][99]

Countries where CBD is illegal

Although CBD is illegal or controlled in each of these countries, there may be regional or circumstantial (e.g. religious) exceptions, as noted below:

• Australia (medical only)^[100]
• Bolivia^[94]
• Canada (medical only)^[101]
• Denmark^[94]
• Iceland^[94]
• Russian Federation^[94]
• Serbia^[94]
• Slovakia^[94]

Countries where the law is unclear

Countries that appear to have legislated neither for nor against CBD, or where enforcement is unclear, include:

• Chile (CBD is legal on prescription and cannabis decriminalized; CBD is also reportedly tolerated for non-medical use in Chile but it may not be tolerated in airports)^[94]
• Ecuador^[94]
• Netherlands (CBD is legal and cannabis decriminalized; however CBD oil is illegal although reportedly tolerated)^[94]
• Uruguay (CBD is legal on prescription and cannabis decriminalized for citizens/residents; it’s unclear whether CBD is legally available for non-citizens/non-residents)^[94]

Can it be detected in a drug test?

CBD isn’t really screened for but full-spectrum products may flag a positive for THC.^[54]

A single use of CBD has an elimination half-life of 18-32 hours; it can take a day and a half to leave your system.^[113] But after a period of chronic (e.g. daily) use, it could remain in your system for 2-5 days.^[41]

Are there risks?

Aside from drug interactions and possible contraindications or allergies, CBD is pretty well tolerated. Side effects, affecting roughly one in three people, are mild. Start small, avoid potentially risky activities (at least while you gauge your response), and it shouldn’t pose any risk to your health whatsoever.

How do I take CBD?

The most common routes of administration are oral (capsules), sublingual (oil, tincture), and inhaled (vaped). After working out your dose, take your CBD as below:

• Capsules: With food (e.g. before or after a meal) high in fatty acids, such as fish, avocado, or eggs
• Oil or tincture: Hold under the tongue for 60-90 seconds before swallowing
• Vape: Methods vary, so refer to manufacturer/supplier instructions. But ensure you have a CBD product for vaping; don’t try to vape ordinary CBD oil

What is hemp?

Botanically, the hemp plant is cannabis; they’re the same species. However, the 2018 Farm Bill defines “hemp” as cannabis containing no more than 0.3% THC by dry weight. It’s also called “industrial hemp.”

How to grow hemp?

In most countries you need a license to grow hemp. Even in the United States after the Farm Bill legalized the crop, you still need a license to grow it. Find out more from your local authority.

How can I make CBD oil?

To make CBD oil, you’ll need cannabis with lots of CBD. Some of the best CBD strains are reputedly Cannatonic, Sour Tsunami, and Harlequin.^[120] First, you’ll need to heat the flowers/buds to make the CBD bioavailable—a process known as decarboxylation.

After harvesting the plant matter, break them into small pieces and arrange in a single layer on a baking sheet. Pre-heat the oven to 200-300 degrees Fahrenheit and gently heat the buds for 30-40 minutes, shuffling them around the baking sheet once every 10-15 minutes.^[114] Once decarboxylated, you can steep your high-CBD buds in a food-grade oil of your choice before straining. Olive, avocado, coconut, and hemp seed oils are popular.^[115]

This isn’t the only way to make your own CBD extract, but it’s probably the easiest and cheapest. The preferred method commercially is CO2 extraction, but this requires sophisticated lab equipment. Alkane (e.g. butane, propane, hexane) extraction is another method, used to make waxy cannabis concentrates like shatter, but it can result in contaminated products—and explosions. Ethanol extraction is a gentler option, and can be used to make a CBD tincture.^[115]

Where can I buy CBD oil?

If it’s legal where you live, you’ll find the widest choice of CBD online. But you can also get CBD from a variety of mainstream retail outlets, in addition to vape stores and dispensaries.

What CBD product should I choose?

There are basically two types of CBD to choose from, regardless of whether you’re vaping or dosing sublingually/orally. CBD isolate is just CBD, whereas full-spectrum products contain THC as well, along with terpenes derived from the cannabis plant. Full-spectrum is generally recommended to maximize CBD benefits. However, if THC isn’t legal where you live, you may be able to find broad-spectrum products instead. These contain other cannabinoids besides THC, or added terpenes derived from the cannabis plant.

Another thing to look out for is the origin of the product. It’s best to go with companies based in states where cannabis is legal, since they’re held to a higher standard owing to the stronger regulatory framework.^[116]

The more transparent the supply chain the better. Given the bioremedial use of hemp to leach toxins from contaminated soil, some products may be unhealthy.^[117]

The CBD subreddit lists a number of companies to avoid, and it’s a good place to look for reviews.

Is CBD oil legal?

CBD oil is legal and widely available in the US, UK, Canada, and (technically, at least) the European Union as well. See Legality for some caveats.

What is the difference between CBD oil and hemp oil?

Hemp oil, or hemp seed oil, is made from hemp seeds and therefore doesn’t contain CBD. However, some use the terms interchangeably—confusingly referring to CBD oil as hemp oil and, more deceptively, vice versa.

What is the difference between hemp-derived and cannabis-/marijuana-derived CBD?

In the US and Canada, hemp-derived products contain no more than 0.3% THC. Cannabis-derived CBD products, on the other hand, may contain substantially more than that.^[117]

You’re less likely to benefit from the synergistic “entourage effect” with hemp-derived products.

Can I microdose with CBD?

Microdosing CBD apparently works for some people. But it’s hard to gauge what constitutes a microdose (or whether it’s even a microdose at all) from anecdotal reports because of the high variability of products.

Will it produce tolerance?

Until recently, there was basically no evidence of a tolerance effect from CBD^[35]—but there hadn’t been many long-term studies. Numerous anecdotal reports claim that tolerance builds up over time.^[118] And one study appears to agree. Of 92 patients with treatment-resistant epilepsy, given an average dose of 12.6 mg/kg/day, 32.6% developed tolerance after an average of 7.3 months.^[119]

Can I mix it with other drugs?

Drugs metabolized by the same enzymes as CBD may be affected. See Drug interactions for details.