Cannabis

BotanicalBest in the evening

What is it

Cannabis (Cannabis sativa, including Cannabis indica varieties) is a flowering plant whose leaves, flowers, and resin contain over 100 cannabinoid compounds, most notably tetrahydrocannabinol (THC), the principal psychoactive component, and cannabidiol (CBD), a non-intoxicating cannabinoid with anti-seizure and anti-inflammatory properties. Legal status varies widely by jurisdiction.

Evidence for 5 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Refractory pediatric epilepsy

Strong Evidence

Purified CBD (Epidiolex) is FDA-approved and effective for Dravet and Lennox-Gastaut syndromes.

Chemotherapy-induced nausea

Strong Evidence

Cannabinoids (dronabinol, nabilone) are established options when first-line antiemetics fail.

Chronic pain

Good Evidence

Modest pain reduction in chronic pain and multiple sclerosis spasticity. Effect sizes are moderate.

Anxiety

Limited Evidence

Some CBD trials suggest reduced anxiety; results are mixed and product variability is high.

Sleep

Limited Evidence

Some evidence for short-term improvements in sleep with CBD or cannabis; tolerance and rebound concerns exist.

How it works

Cannabinoids act on the endocannabinoid system, primarily CB1 receptors (concentrated in the brain) and CB2 receptors (concentrated in immune cells). THC is a partial agonist at CB1, producing intoxication, analgesia, appetite stimulation, and other effects. CBD has complex, mostly non-CB1 effects including positive modulation of GABA-A receptors, TRPV1, serotonin 5-HT1A, and adenosine receptors, and inhibition of FAAH (which raises endogenous endocannabinoid levels). FDA-approved cannabis-derived medications include dronabinol (synthetic THC, for chemotherapy-induced nausea and AIDS-related anorexia), nabilone (synthetic THC analog), and CBD-based Epidiolex (for specific epilepsy syndromes). Many non-FDA cannabis and CBD products are sold over the counter.

Dosage

Highly variable depending on form, route, indication, and tolerance. CBD doses in clinical trials range from 25 to 1,500 mg per day. THC dosing varies by product and individual sensitivity.

When and how to take it

Highly variable depending on formulation. Oral edibles take 1 to 2 hours to peak; inhaled cannabis acts within minutes. Sleep formulations are typically taken in the evening. CBD for anxiety or epilepsy is usually divided across the day.

3 commercial forms

Compare the main delivery options and what they’re best suited for.

CBD oil/tincture (hemp-derived)

Most widely available legal form in the U.S. (hemp source, <0.3% THC).

Sublingual absorption is moderate.

Inhaled cannabis

Legal status varies by jurisdiction.

Rapid onset, short duration.

Edibles (oral)

Risk of unintentional overdose due to delayed effects.

Slow onset (1-2 hours), longer duration.

Safety

Acute effects of THC include impaired cognition, anxiety/panic, paranoia, and cardiovascular effects. Long-term THC use raises risk of cannabis use disorder, cognitive effects in adolescents, and psychiatric outcomes in vulnerable individuals. CBD is generally well tolerated; high doses can cause sedation, diarrhea, and liver enzyme elevations.

Who should be cautious

Avoid in pregnancy and breastfeeding (THC and possibly CBD reach the fetus and infant). Avoid in adolescents (developing brain). Use cautiously in people with a history of psychosis, severe heart disease, liver disease, or on multiple medications. Legal restrictions vary by location.

Interactions

Cannabinoids inhibit CYP3A4, CYP2C9, CYP2C19, and CYP2D6, potentially affecting numerous medications. Major interactions with warfarin, immunosuppressants, antiepileptics, and antidepressants. Additive sedation with alcohol and CNS depressants.

Documented interactions

Evidence-graded pair pages with sources, dosing notes, and timing guidance — a complement to the narrative section above.

Warnings (1)

+ ssris

high

Cannabinoids inhibit liver enzymes (including CYP2C19) that clear several SSRIs such as sertraline, citalopram, and escitalopram, which can raise SSRI plasma levels. Cannabinoids also touch the serotonin system, and case reports describe serotonin syndrome precipitated by high-potency cannabis in patients on serotonergic regimens.

See all 1 Cannabis interaction →

Frequently asked questions

Is CBD legal?⌄

Hemp-derived CBD (<0.3% THC) is federally legal in the U.S. under the 2018 Farm Bill, though state and local regulations vary. THC-containing products have more complex legal status.

Will CBD show up on a drug test?⌄

Pure CBD typically does not, but many CBD products contain trace THC that can accumulate and produce positive tests.

Is cannabis safe to use daily?⌄

THC-containing daily use carries risk of dependence and cognitive/psychiatric effects. CBD is generally better tolerated but high doses can affect the liver.

References

Cannabis on Wikidata — Wikidata link

Cannabis on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Cannabis (PubMed search) — PubMed link

Track Cannabis with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

Coming to App Store
Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.