INTRODUCTION
Hair thinning and loss is highly prevalent in the adult population. Estimates suggest that by age 50, approximately 50% of men will experience some degree of hair loss secondary to androgenetic alopecia (AGA).1 AGA is also a common cause of hair loss among women.2 AGA is thought to be due to a constellation of hormonal and genetic influences. More broadly, hair loss has been associated with a range of nutritional, hormonal, inflammatory, genetic, and environmental factors.3 The effects of hair loss can be devastating, with many patients reporting decreased self-esteem and quality of life.4-7 Furthermore, studies have demonstrated that men who are balding are rated less favorably in social domains of attractiveness, successfulness, and likeability compared with their non-balding counterparts.8,9 This psychosocial impact of hair loss motivates patients to seek treatment, both from medical providers and the unregulated marketplace. To date, two medications have been approved by the Food and Drug Administration (FDA) for use in AGA minoxidil and finasteride.10 Clinical trials have demonstrated the efficacy of topical minoxidil in the treatment of AGA in men and women, and this product is available over-the-counter (OTC).11,12 Finasteride is approved in men with AGA and may be obtained only with a prescription.13 In addition to these FDA-approved interventions, there are myriad hair loss treatments available for purchase OTC. Evidence supporting the use of these treatments, however, is often limited. Despite a lack of clinical data regarding these interventions, consumers frequently purchase these products and may be actively using these treatments when they present for evaluation of hair loss. As the experts in disorders of the hair, dermatologists should be knowledgeable about popular OTC treatments and the available evidence regarding their use. This study aims to provide an overview of products that are frequently purchased OTC to treat hair loss and to evaluate the data supporting their use.
METHODS
A list of popular hair loss products was generated using data from the online retailer Amazon.com. A regularly updated list of the top-selling hair loss products is made available to the public under the “Amazon Best Sellers†in Beauty and Personal Care > Hair Care > Hair Loss Products. We collected data on the top 50 products included within the best seller list on July 24, 2018. Hair loss treatments including shampoos/conditioners, serums, foams, oils, and oral supplements were included. Products like hair building fibers and those not intended to specifically treat hair loss on the scalp were excluded. Data collected included: active ingredients, price, quantity, product rating, and number
