http://www.ncbi.nlm.nih.gov/pubmed/3200111 Yet another study I'm curious about the relevance to Androgenetic Alopecia. This study mentions that nicotine and its metabolite cotinine inhibit the HSD enzyme which prevents the metabolism of DHT into a less potent androgen. While I don't smoke regularly at all (literally 1-5 packs over the course of a year, spread out throughout the year too, it's usually a once every few months type thing) I do use 2mg nicotine gum usually twice a day during exam periods (for 2-3 weeks, 4 times a year). Is this something to be concerned about or is it mostly irrelevant? If it's any consolation noticed my hair loss accelerate slightly after the June exam period this year.