Botanicals in Dermatology: An Evidence-based Review

Juliane Reuter; Irmgard Merfort; Christoph M. Schempp


Am J Clin Dermatol. 2010;11(4):247-267. 

In This Article

5. Hair Loss and Alopecia

There is increasing interest in the cosmetic industry in the development of products containing botanicals to treat or prevent hair loss and alopecia. Some botanical extracts are traditionally used to promote hair growth without scientific support, like birch sap in hair tonics. Garlic (A. sativum) is used topically in India, but is associated with obvious olfactory adverse effects. A single-blinded clinical trial was designed to test the effectiveness of topically applied crude onion juice (Alliumcepa), which has many sulfurous ingredients.[116] Sixty-two male and female patients with patchy alopecia areata were treated with fresh onion juice in comparison with tap water, applied twice daily for 2 months. Only 23 patients in the active treatment group and 15 control patients finished the study. However, the use of crude onion juice gave significantly better results with regard to hair regrowth than did tap water[116] [LOE-B].

A standard medication for male androgenic alopecia is finasteride, a potent inhibitor of 5α-reductase, which converts testosterone to dihydrotestosterone. Finasteride was originally developed for the treatment of benign prostatic hyperplasia. Plants containing phytosterols like β-sitosterol or phytosterol glycosides, such as the palm tree saw palmetto (Serenoa repens), are traditionally used for benign prostatic hyperplasia treatment, and the same mechanism is discussed as their mode of action. Therefore, it was intriguing to test botanical 5α-reductase inhibitors in androgenic alopecia. In a randomized, double-blind, placebo-controlled pilot study with 26 male subjects, the effectiveness of a combination of β-sitosterol 50 mg and extract from the berries of saw palmetto 200 mg twice daily in the treatment of androgenic alopecia was determined.[117] Ten patients were treated over 5 months with the active study formula. The blinded investigative staff assessment report showed that 60% of the study subjects were rated as improved at the final visit compared with only 11% of the placebo group[117] [LOE-A]. Because of the small sample size, statistical significance was not the primary aim of the study. The formulation was well tolerated; one patient reported loss of appetite possibly related to active treatment. In contrast to finasteride, the tested botanical 5α-reductase inhibitors have no impact on prostate-specific antigen levels and do not interfere with cancer diagnostics.[118] They are also widely used traditionally by women for a variety of indications without safety problems, so they may also be tested in androgenic alopecia in women.[119]


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