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CBD (Cannabidiol)
A non-intoxicating cannabis compound: strong (prescription, high-dose) evidence for specific seizure disorders, but only promising-to-mixed evidence for the OTC wellness uses (anxiety, pain, sleep), plus notable drug interactions.
What the evidence says
CBD doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from high-quality meta-analyses and randomised trials published 1979–2026 with a typical study size of 12,123 participants.
Based on 460 studies · 58 meta-analyses · 249 RCTs · 15,190 total participants
Confidence
High confidenceBy outcome
15 more outcomes with fewer studies not shown.
Strong RCT/meta-analytic evidence for prescription-dose seizure control, but only promising-to-mixed wellness-dose data for anxiety, pain, and sleep, plus real safety caveats, pulls the overall score to moderate.
234 trials ongoing or recruiting · 566 completed on ClinicalTrials.gov
206 of the completed trials have posted results
Registered trials show research momentum for CBD, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Oct 2026
CBD (cannabidiol) is a non-intoxicating compound from cannabis/hemp (it does not cause the 'high' that THC does). Its evidence is sharply two-tiered.
As the prescription drug Epidiolex — at high, weight-based doses — it is FDA-approved and well-proven for rare seizure disorders (Dravet, Lennox-Gastaut, tuberous sclerosis).
As an OTC wellness supplement at much lower doses, the evidence for anxiety is promising but limited, for chronic pain mixed, and for sleep weak (a controlled trial found 150mg nightly no better than placebo on sleep metrics).
Importantly, CBD inhibits liver CYP enzymes (like grapefruit), can raise blood levels of many medications, and is associated with dose-dependent liver-enzyme elevations. OTC products are also poorly regulated, with frequently inaccurate labeled potency.
Indirectly influences CB1/CB2 signaling and raises endocannabinoid (anandamide) tone, affecting stress, pain, and inflammation.
Activates 5-HT1A receptors, a proposed basis for anxiolytic and some analgesic effects.
Acts on TRPV1 and inflammatory pathways implicated in pain and inflammation.
Reduces neuronal excitability (in part via GPR55 and calcium handling) — the basis of its proven anti-seizure effect at prescription doses.
Check with a pharmacist/clinician — CBD has grapefruit-like CYP drug interactions affecting many drugs.
Avoid — safety not established; FDA advises against CBD in pregnancy.
Avoid or use only with monitoring — dose-dependent liver-enzyme risk.
CBD raises clobazam levels via CYP2C19 — increased sedation/toxicity; needs dose adjustment.
CBD can raise warfarin levels (CYP2C9/3A4) — monitor INR closely.
Additive risk of liver-enzyme elevation/hepatotoxicity.
CBD can inhibit drug-metabolising enzymes, and the Epidiolex label describes moderate CYP2C19 inhibition. Whether it raises the level of a particular medicine depends on the medicine, the CBD product and the dose, and CBD can add to the drowsiness some of these medicines cause. Not every medicine broken down by these enzymes is affected in the same way. Ask your prescriber or pharmacist to review the combination, and do not change your medicine yourself. This precaution has no severity grade. The size of any effect for this product has not been established, so it is shown for you to raise with a pharmacist, not as an assessed risk or an all-clear. Do not stop or change prescribed medicines based on this notice.
Additive sedation/drowsiness.
Tip: Lower dose; avoid with other sedatives; take in the evening
Tip: Reduce dose; take with food
Tip: Monitor
Tip: Avoid high doses and valproate; check liver enzymes if using high-dose long-term
CBD has an evidence score of 5.8/10 — moderate evidence based on 460 indexed studies, including 6 meta-analyses. A non-intoxicating cannabis compound: strong (prescription, high-dose) evidence for specific seizure disorders, but only promising-to-mixed evidence for the OTC wellness uses (anxiety, pain, sleep), plus notable drug interactions. Representative study: PMID 36206805.
Dosing for CBD: OTC wellness: 10-50mg/day (some anxiety studies used higher acute doses ~300mg); take with a fat-containing meal (increases absorption several-fold). Prescription Epidiolex for epilepsy is dosed by body weight under medical supervision. (the 10-50mg figure is a typical label dose, the cited trials used 150 mg nightly, or 10 to 20 mg per kg a day of prescription cannabidiol for epilepsy). Individual needs vary — start at the lower end of the range and adjust based on how you respond.
The best time to take CBD is with meals. Take it with food. Taken with a fat-containing meal, which can increase CBD absorption ~4-5x.
CBD should be used with caution — talk to a healthcare provider before taking it. Reported side effects include liver-enzyme elevation, somnolence/sedation, fatigue, diarrhea / GI upset. How often they occur is not established for all of them. Use caution if any of these apply to you: Concurrent use of CYP3A4/CYP2C19-metabolized drugs (incl. clobazam, some statins, blood thinners) without medical supervision; Liver disease or elevated liver enzymes; Pregnancy and breastfeeding.
Omega-3
Probably helpsEssential fatty acids critical for brain health, mood regulation, and reducing inflammation throughout the body.
Curcumin
Probably helpsTurmeric's active compound that modulates NF-kB inflammatory pathways — supports mood, joint health, and post-exercise recovery.
Melatonin
Likely helpsRegulates the circadian clock to reduce sleep onset time — most effective at low doses (0.3-1mg) for jet lag and rhythm disorders.
CoQ10
Likely helpsA lipid-soluble antioxidant central to mitochondrial energy production, with the strongest trial support for fertility/IVF outcomes and heart failure.
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Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 460 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.