4-Androstenediol

**4-Androstenediol** is a synthetic and naturally occurring steroid hormone that serves as a direct precursor in the biosynthesis of testosterone. It is structurally closer to testosterone than its positional isomer, 5-androstenediol. In the body, it is converted to testosterone at a rate of approximately 15.76%, which is higher than that of related compounds such as androstenedione due to utilization of a different enzymatic pathway[8][5]. It also undergoes some conversion into estrogens since testosterone itself can be aromatized. Pharmacologically, it acts as an androgen with weak partial agonist activity at the androgen receptor; in the presence of more potent endogenous androgens like testosterone or dihydrotestosterone (DHT), it may exhibit antagonistic (antiandrogenic) effects due to its lower intrinsic activity[8]. Additionally, it has very weak estrogenic properties—about 0.5–0.6% affinity for estrogen receptors compared to estradiol[8]. Historically marketed as a dietary supplement for purported benefits such as increased muscle mass or athletic performance enhancement, its use has been banned by major sports organizations and reclassified in many jurisdictions (including the US) as a controlled substance due to concerns about misuse and health risks[2][3][1].

Other names

androst-4-ene-3β,17β-diol4-androstene 3,17-diol4-androstene-3beta,17beta-diol