No regulator has set a CBD dose, so every number you have seen was picked by a marketer or a trial protocol. This page collects the sourced ones.
The short answer
There is no established dose — only sourced ranges.
Sleep trials have run 25 mg to 300 mg+ per evening. Prescription cannabidiol runs 5–20 mg/kg a day under supervision — several hundred milligrams for an adult. Retail labels start near 10–25 mg, and the weight-based charts everywhere online have no trial behind them.
Where the numbers come from
- Sleep research: 25 mg to 300 mg+ per evening — a 2024 pilot used 150 mg nightly, a crossover trial 300 mg with terpenes.
- Prescription cannabidiol: Epidiolex, 2.5 to 10 mg/kg twice daily, for rare seizure disorders under supervision.
- Retail labels: roughly 10–25 mg per serving; 50 mg in “extra strength” lines.
The milligram figure is a claim. A 2017 JAMA analysis measured 84 CBD products from 31 companies: 30.95% were accurately labelled, 42.85% held more than stated, 26.19% less. THC turned up in 18 of the 84, up to 6.43 mg/mL.
Absorption and onset by format
| Format | Onset | Duration | What reaches your blood |
|---|---|---|---|
| Oil under the tongue | 15–30 min | 4–6 hr | Never measured. Held 60–90 seconds before swallowing |
| Gummy or capsule | 60–120 min | 4–8 hr | Never measured. A high-fat meal raised peak levels 5-fold (Epidiolex trials). |
| Topical cream or balm | 15–45 min | 2–4 hr | Local only; minimal systemic absorption |
| Inhaled | 5–15 min | 2–3 hr | 31% for smoked CBD — the only measured route. Lung risks |
A 2018 systematic review found absolute bioavailability has never been established in humans for oral or sublingual CBD — the formats almost everyone buys.
The start-low protocol
“Start low, go slow” is a convention, not a finding. The schedule that circulates: about 10–15 mg for three days, 20–25 mg through the first week, then 25–50 mg in the second week if nothing registers — steps from label serving sizes, not a trial.
Overshooting, per the FDA: drowsiness, digestive upset, appetite and mood changes.
When nothing happens
Two weeks at the top of a label range with nothing to show is a result, not a failure.
The claim that CBD reaches steady state in four to seven days has no settled basis. Reported half-lives run 1.4 to 10.9 hours for an oromucosal spray, 2 to 5 days with chronic oral use, and 56 to 61 hours in the Epidiolex trials.
The other explanations are format, product, and the problem itself — the sleep evidence is split.
Who should not use it
- Anyone on prescription medication. CBD is metabolised by CYP3A4 and CYP2C19; the Epidiolex label records a 3-fold rise in clobazam’s active metabolite. Blood thinners, antidepressants and seizure drugs share those pathways.
- Pregnant or nursing. Don’t.
- Anyone with liver concerns. In the Epidiolex trials 13% had ALT above three times the upper limit of normal, against 1% on placebo. The FDA says CBD can cause liver injury.
- Anyone subject to drug testing. THC appeared in 18 of those 84 products.
- Anyone whose problem has lasted weeks. That’s a provider, not a supplement.
Before you spend anything
Do the free things first. Schedule, light and caffeine timing move more than any milligram figure here; the basics cost nothing.
If you still want the experiment: one product, one level, two weeks, written down. Our what the sleep trials actually dosed covers certificates of analysis.
Sources
- A Systematic Review on the Pharmacokinetics of Cannabidiol in Humans — Frontiers in Pharmacology, 2018;9:1365.
- EPIDIOLEX (cannabidiol) oral solution — prescribing information — U.S. Food and Drug Administration, 2018.
- Labeling Accuracy of Cannabidiol Extracts Sold Online — JAMA, 2017;318(17):1708–1709.
- What You Need to Know About Products Containing Cannabis or Cannabis-Derived Compounds — U.S. Food and Drug Administration.
- Use of Cannabidiol in the Management of Insomnia: A Systematic Review — Cannabis and Cannabinoid Research, 2022.
- Cannabidiol for moderate–severe insomnia: a randomized controlled pilot trial of 150 mg of nightly dosing — Journal of Clinical Sleep Medicine, 2024;20(5):753–763.
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These statements have not been evaluated by the Food and Drug Administration. CBD products are not intended to diagnose, treat, cure or prevent any disease. Serene Leaf does not physically test products; our assessments are based on published research, third-party lab reports and publicly available product information.
This article is information, not medical advice. Talk to a qualified healthcare provider before starting any supplement — especially if you are pregnant, nursing, taking medication or managing a diagnosed condition. 21+ only.