Encyclopedia · botanical
Cannabinoids and CBD
A hemp-oil case series claims a 93.5% rise in hair count in 35 people, but it had no control group; lab data hint CBD may lift a growth signal in papilla cells while higher doses could push follicles into regression.
What it is
CBD is a non-intoxicating cannabis compound sold as topical oils. Legal status varies by country and product, and no hair claim is approved.
How it works
Proposed: the follicle has endocannabinoid-system receptors, and CBD may act on CB1 and TRPV1/TRPV4 signalling and boost Wnt. The case-series authors state that higher doses may trigger early regression via TRPV4. Smith 2021 In cultured dermal papilla cells, CBD countered a drop in beta-catenin (we read only the title). Park 2021
What the studies show
- In an uncontrolled case series of 35 men and women with pattern hair loss, once-daily topical hemp oil (about 3-4 mg CBD/day) for 6 months was reported to raise hair count by an average of 93.5%, men slightly more than women, with no adverse effects reported. There was no control group or blinding, and the authors are private-practice clinicians. Smith 2021
- A companion case series on a novel hemp extract exists (title only read). Smith 2023
- No placebo-controlled trial was found (search 2026-10-10).
How it's used in studies
Topical hemp oil, about 3-4 mg CBD daily in the case series.
Side effects and safety
None reported in the series, but 35 people cannot detect rare problems. Product purity varies widely.
Bottom line
The effect size is implausibly large for an uncontrolled count and should not be taken as evidence. Randomized trials are missing.
Fun facts
- A 35-person case series reported a 93.5% rise in hair count from hemp oil, one of the largest claimed effects in the hair literature and a good example of why uncontrolled studies mislead. Smith 2021
Studies 3
Smith GL, Satino J. Hair regrowth with cannabidiol (CBD)-rich hemp extract in men and women with androgenetic alopecia: a case series. Cannabis Cannabinoid Res. 2021
Tested: topical hemp oil, about 3-4 mg CBD/day
Result: Reported 93.5% average hair increase; no control group or blinding.
Read the study ↗Smith GL, Satino J. Hair regrowth with novel hemp extract: a case series. 2023
Result: Companion uncontrolled case series (title only read).
Read the study ↗Park YJ et al. Regulatory effect of cannabidiol on decreased beta-catenin expression in alopecia models. 2021
Result: CBD countered reduced beta-catenin expression in alopecia models (title only read).
Read the study ↗Related
- MinoxidilThe most widely used hair-growth treatment, available as a cheap over-the-counter lotion or foam and as a prescription tablet, with a mechanism that is still only partly understood.
- FinasterideA prescription pill (and in some countries a scalp spray) that lowers DHT and is the best-proven drug for stopping male pattern hair loss.