S-23 is widely touted as the most powerful SARM on the market. It is unique in its ability to allow users to build slabs of muscle, maintain fullness and strength while stripping fat. Its aesthetic benefits have been likened to Anavar and Stanazolol for that reason, since it dramatically hardens the physique.
However, S-23 can deplete testosterone levels more noticeably than other SARMs, which require users to use post-cycle therapy (PCT). This SARM has also attracted strong interest for its potential to be used as male birth control. However, high doses had an inverse effect and supported sperm production. In rats, S23 led to temporary infertility in 100% of cases. This was reversed upon immediate cessation of dosing in all cases.
In a study on rats, S-23 decreased body weight and fat mass. To promote mating, there its were also given an estrogen (estriadol benzoate), which causes muscle loss. S23 was able to override the effects of estrogen and increase lean muscle mass.
S23 decrees fat in a dose dependent manner, higher doses melting more fat. In another study, S23 prevented muscle loss from glucocorticoids. Glucocorticoids are commonly used anti-inflammatory drugs and naturally present in the body. But their long term use can cause serious muscle loss, insulin resistance and elevated blood sugar levels. Inhibiting glucocorticoid activity with S23 could achieve the growth of fast twitch muscle fibres and slow twitch muscle fibres. It also improves the rate at which your body metabolises carbohydrate. It also reduces visceral body fat stores around the abdomen.
Users compare the effect to the lean hardness gained on MK-2866 coupled with the fullness that can be attained with LGD-4033.