Case Study of Hair Regrowth with Topical Cannabidiol (CBD)

Introduction: Discovered in the 1990s, the endocannabinoid system (ECS) is involved with maintaining cellular homeostasis by downregulating the damaging inflammatory response and upregulating regenerative processes. Cannabidiol (CBD) has novel therapeutic effects, different from and synergistic with current hair regrowth therapies. CBD is fat-soluble and poorly absorbed past the epidermis, but topical application of CBD easily reaches hair follicles where it is a CB1 antagonist and agonist of vanilloid receptor-1 (TRPV1) and vanilloid receptor-4 (TRPV4). All these ECS receptors relate to hair follicle function. Blocking the CB1 receptor on the hair follicle with CBD has been shown to result in hair shaft elongation; in addition, the hair follicle cycle (anagen, catagen, and telogen phases) is controlled by TRPV1. The effects of CBD on hair growth are dose dependent and higher doses may result in premature entry into the catagen phase via a different receptor known as TRPV4. CBD has also been shown to increase Wnt signaling, which causes dermal progenitor cells to differentiate into new hair follicles and maintains anagen phase of the hair cycle.

Objective: This study was conducted to determine if daily topical application of a hemp oil high in CBD concentration would result in significant hair regrowth in the area of the scalp most affected by androgenetic alopecia (AGA).

Methods: A study was done of 35 (28 men and 7 women) subjects with AGA. Participants used a once daily topical CBD formulation, averaging about 3-4mg per day for 6 months. A hair count of the greatest area of alopecia was carried out before treatment started and after 6 months of treatment. To facilitate consistent hair count analysis, a clear acrylic mold, containing a 1cm² cutout, was made of each subject’s head.

Results: The results revealed that men did slightly better than women, and the vertex area did better than the temporal areas. On average, there was a statistically significant 93.5% increase in nonvellus hair after 6 months of once daily use. All subjects had some regrowth. There were no reported adverse effects.

Discussion: Though the exact mechanism of therapeutic effects is not known, CBD is most likely functioning as a CB1 receptor antagonist and potentially also via Wnt messaging. Topical CBD formulation has comparable results to finasteride and comparable results to 5% minoxidil once daily foam. Since the CBD works through novel mechanisms different from finasteride and minoxidil, it can be used in conjunction with these current drugs and would be expected to have synergistic effects. However, safety of this combination would need to be evaluated.