4-Androstenediol Explained

4-Androstenediol, also known as androst-4-ene-3β,17β-diol, is an androstenediol that is converted to testosterone. The conversion rate is about 15.76%, almost triple that of 4-androstenedione, due to utilization of a different enzymatic pathway. There is also some conversion into estrogen, since testosterone is the metabolic precursor of the estrogens.

4-Androstenediol is closer to testosterone structurally than 5-androstenediol, and has androgenic effects, acting as a weak partial agonist of the androgen receptor.^[1] However, due to its lower intrinsic activity in comparison, in the presence of full agonists like testosterone or dihydrotestosterone (DHT), 4-androstenediol has antagonistic actions, behaving more like an antiandrogen.

4-Androstenediol is very weakly estrogenic. It has approximately 0.5% and 0.6% of the affinity of estradiol at the ERα and ERβ, respectively.^[2]

Medical and commercial use

Patrick Arnold holds a 1999 patent on "Use of 4-androstenediol to increase testosterone levels in humans".^[3]

Notes and References

1. Chen F, Knecht K, Leu C . Partial agonist/antagonist properties of androstenedione and 4-androsten-3beta,17beta-diol . The Journal of Steroid Biochemistry and Molecular Biology . 91 . 4–5 . 247–57 . August 2004 . 15336702 . 10.1016/j.jsbmb.2004.04.009 . 53267316 . etal .
2. Kuiper GG, Carlsson B, Grandien K, Enmark E, Häggblad J, Nilsson S, Gustafsson JA . Comparison of the ligand binding specificity and transcript tissue distribution of estrogen receptors alpha and beta . Endocrinology . 138 . 3 . 863–70 . 1997 . 9048584 . 10.1210/endo.138.3.4979 . free .
3. Web site: Use of 4-androstenediol to increase testosterone levels in humans . 2011-03-18 . dead . https://web.archive.org/web/20110318185140/http://www.patentstorm.us/patents/5880117/description.html . 2011-03-18 .