S23 CAS:1010396-29-8

S-23 is an investigational selective androgen receptor modulator developed by GTX, Inc as a potential male hormonal contraceptive. It binds to the androgen receptor more strongly than older drugs such as andarine with a Ki of 1.7 nM, and in animal studies it showed both a good ratio of anabolic to androgenic effects, and dose-dependent suppression of spermatogenesis with spontaneous recovery after cessation of treatment.

Developed by GTx, S-23 is an orally active nonsteroidal SARM with a very high binding affinity to androgen receptors. This makes it stronger than other popular SARMS like Ostabolic (mk-2866) or Andarine (S-4). Therefore, the main effects of S-23 are increased muscle mass, decreased fat mass, and a decrease in the size of the prostate. Additionally, in a study done on rats a dose equivalent to 15 milligrams (mg) for a 180lb male was shown to also increase bone mineral density, as well as promote muscle mass growth and fat loss. Hence, S-23 is versatile in that it can be used for bulking and for cutting. S23 or (2S)-N-(4-cyano-3-trifluoromethylphenyl)-3-(3-fluoro-4-chlorophenoxy)-2-hydroxy-2-methyl-propanamide is a new SARM, which is developed as a possible male hormonal contraceptive. It links to the androgen receptor (AR) more intensely (with a Ki of 1.7nM) as compared to older medicines such as Andarine.

As of today, what we know is that S23 is an easy-to-dose oral SARM that can boost lean muscle mass growth while being tissue selective at the same time.

Sarms S23 is an investigational selective androgen receptor modulator (SARM) developed by GTX, Inc as a potential male hormonal contraceptive. It binds to the androgen receptor more strongly than older drugs such as andarine with a Ki of 1.7 nM, and in animal studies it showed both a good ratio of anabolic to androgenic effects, and dose-dependent suppression of spermatogenesis with spontaneous recovery after cessation of treatment.

S-23 not only boosted muscle mass, but also reduced fat mass, as studied. SARMs have a bit of a ‘soft’ image in the doping world. They don’t stimulate muscle growth in the way that anabolic steroids do, but many users say that they are safer.

There are no studies yet that confirm this suspicion. But that S23 is not one of the safer SARMs – we’d be willing to wager a bottle of BCAAs on that. S23 halts the production of sperm in the testes. In fact it does this so well that the researchers suspect S23 might be a good candidate for a male contraceptive. If this is the case it would probably have to be part of a cocktail that also contains an estradiol analogue, the researchers discovered. The lab animals lost their libido when they were given S23 on its own, and only recovered this when they were given estradiol benzoate together with the S23.