Saw palmetto (SP), a botanical extract with antiandrogenic properties, has gained commercial popularity for its purported benefits on hair regrowth. To summarize published evidence on the efficacy, safety, and tolerability of supplements containing SP in the treatment of alopecia, we conducted a PubMed, Google Scholar, and Cochrane database search using the following terms: (saw palmetto and hair loss), (saw palmetto and androgenetic alopecia), and (saw palmetto and natural supplement and alopecia). Five randomized clinical trials (RCTs) and 2 prospective cohort studies demonstrated positive effects of topical and oral supplements containing SP (100-320 mg) among patients with androgenetic alopecia (AGA) and telogen effluvium. Sixty percent improvement in overall hair quality, 27% improvement in total haircount, increased hair density in 83.3% of patients, and stabilized disease progression among 52% were noted with use of various topical and oral SP-containing supplements. SP was well tolerated and not associated with serious adverse events in alopecia patients. Although robust high-quality data are lacking, supplements containing SP may be a treatment option for patients with AGA, telogen effluvium, and self-perceived hair thinning. Further large-scale RCTs focusing on the sole contribution of SP to hair growth outcomes are needed to confirm efficacy and determine long-term adverse events.

Smoking is not only a preventable cause of significant systemic disease but also affects the follicular growth cycle and fiber pigmentation. Ambient tobacco smoke exposure results in nicotine accumulation in hair follicles and the hair shaft. This review summarizes the evidence on the association between smoking and hair health, as denoted by alopecia and premature hair graying (PHG). In July 2020, a review of the literature using PubMed/MEDLINE and CINAHL databases identified 32 studies investigating the relationship between smoking, PHG, and alopecia (androgenetic alopecia and frontal fibrosing alopecia). The prevalence of hair loss and PHG is more prevalent in smokers than nonsmokers. Smoking is associated with negative effects on hair health as evidenced in PHG and alopecia. Smoking status should be assessed in patients who are presenting to their dermatologist for evaluation of alopecia and PHG.