An androstadiene is a derivative of androstane which has two double bonds.
Androsta-1,4-diene-3b-ol-17b-one, commonly referred to as 1,4-androstadiene, is a synthetic androgen and a derivative of the steroid hormone testosterone. It is often studied for its potential effects in bodybuilding and athletic performance due to its anabolic properties. Additionally, it has been investigated for its role in hormone replacement therapy and its effects on muscle growth and fat loss. However, its use in sports is typically banned due to its performance-enhancing effects.
Yes, some are still legal. There are some that are legal and can actually be considered supplements and some that are just "grey area" unbanned steroids. I will list most of them below, to the best of my memory:Legal prohormones considered supplements:Delta-2-androst-17-oneandrosterone1-androsterone4-androsteroneLegal hormonal considered supplements (may be anti-estrogenic or anti-cortisol)Androst-3,5-dien-7,17-dione7-Keto DHEA7-OH DHEAandrenosterone AKA 11-ketoandrostenedione11-ketotestosterone"grey market steroids"2a-3a-epithio-17a-methyl-5a-androstan-17b-ol2a, 17a-dimethyl-17b-hydroxy-5a-etiocholan -3-one4-chloro-17a-methyl-4-ene-3,17 diol4-chloro-17a-methyl-1,4-diene-3,17 diol[3,2-c]pyrazole-5alpha-etioallocholane-17beta-tetrahydropyranol13-ethyl-3methoxygona-2, 5(10)-dien-17-one17a-methyl-1,4-Androstadiene-3,17diol