Abstract
Steroidogenic routes to androgens have been discovered and characterized over the last two decades that fall outside the Δ4 and Δ5 "classical androgen pathways" to testosterone and 5α-dihydrotestosterone. There has been considerable investigation into these routes that has come with natural inconsistencies and overlap in naming that can make it difficult to discover information about them as might be needed in a clinical context. This expository review uses "alternative androgen pathways" to include what has been called the "backdoor" pathway to 5α-dihydrotestosterone, the 5α-dione pathway and pathways to 11-oxygenated steroids. A brief history of what led to the discovery of these pathways, basic information about the steroids and proteins involved in their biosynthesis as well as a summary of clinically significant findings is provided. PubChem CIDs for all steroids have been compiled to help authors avoid naming errors in their work. Modest suggestions for future work in these pathways are also given at the end. Patient comprehension and the clinical diagnosis of relevant conditions such as hyperandrogenism can be impaired by the lack of clear and consistent knowledge of alternative androgen pathways; the authors hope this review will accurately disseminate such knowledge to facilitate the beneficial treatment of such patients.