Caffeine as an Active Ingredient in Cosmetic Preparations Against Hair Loss: A Systematic Review of Available Clinical Evidence.

抄録

Background/Objectives: Hair loss (alopecia or effluvium) can significantly affect the self-esteem and psychosocial well-being of patients, resulting in a reduced quality of life. It may herald a systemic disease, nutritional deficiency, or side effects of pharmacotherapy. Current therapeutic options for hair loss are not always satisfactory and may be associated with considerable side effects; therefore, new solutions are still sought. Caffeine seems to be an effective agent against hair loss thanks to its stimulating effects on cell growth and good penetration into the hair follicle. The aim of this study was to systematically review published clinical trials of topical caffeine preparations against hair loss. Methods: We searched PubMed, Scopus, and Web of Science for clinical trials investigating the efficacy of topical caffeine products in hair loss, published until 29 November 2024. The quality of evidence was assessed using the GRADE classification. Results: The query returned 1121 articles, of which 9 ultimately met the inclusion criteria. In total, 684 people with androgenetic alopecia, excessive hair loss, or hair thinning were included in these trials. In all studies, conclusions were in favor of topical caffeine treatment; however, the level of scientific evidence was medium in 3 studies, low in 1, and very low in the remaining 5. Their major flaws included the lack of randomization and placebo and control groups, as well as the lack of information on the caffeine concentration in the topical products. Conclusions: Results from studies published to date suggest that topical caffeine preparations are safe and effective against hair loss. Nevertheless, better-designed clinical trials of well-defined caffeine products are required for an ultimate statement. Commercial hair products with caffeine offered on the market nowadays may be worth a try, but due to incomplete scientific data and product information, satisfactory outcomes are not guaranteed.