诺司替勃（又名去甲氯司替勃）是合成代谢类固醇，雄激素。体育比赛禁用兴奋剂。

注意：此处包括了那些只有微弱男性化效应（或抗男性化（如氧雄龙））的蛋白同化甾类（因为它们合成代谢效应也是通过激活雄激素受体而是显得）。

Note: 21-Hydroxylase inhibitors may also affect androgen levels as they prevent metabolism of androgen steroid precursors.

Norclostebol is an anabolic steroid derived from nandrolone. In particular it is a 4-chloro derivative modified with an acetate ester to slightly slow the release of the steroid in its free form from the injection site. Norclostebol works out to be significantly stronger than pure testosterone. It is approximately 6.6 times as anabolic while only 40% as androgenic. This may not be a particularly fair or valid comparison however. It is more appropriate to compare norclostebol to testosterone propionate due to the use of an ester. In this case they are fairly even in anabolic potency at 112% but only 20-25% as androgenic. In practice this means Norclostebol is a potent anabolic compound with minimal tendency towards side effects. Norclosterbol acetate was first developed as a medicine in 1956 by Piam and given the name Anabol 4-19. The 4-19 is a reference to the particular structure of the steroid. It is a 4-chloro 19-nortestosterone (nandrolone) derivative. Anabol 4-19 production was ceased by the manufacturer many years ago and it is now relatively unknown.