Shortly about Mastorine (S23)

The most effective SARM on the market for building lean muscle mass and strength
Gives a tough appearance and veininess
Has the largest testosterone-suppressing effect compared to other SARMs.

S23 is undoubtedly one of the strongest SARMs in development at the moment. S23 was created by modifying the structure of an older and less effective SARM called C-6 by replacing the para-nitro group of C-6 with a cyano group. Pharmacokinetic studies have shown that C-6 is 76%bioavailable when taken orally, and when the para-nitro group is replaced with a cyano group, S23 is able to achieve 96% bioavailability when taken orally.

Researches

S23 is currently under development for potential use as a male hormonal contraceptive. It is still in the pre-clinical development phase, which means it has only been tested in animals and not in humans. Preclinical data showed that S23 was the most developmentally suppressive SARM and resulted in infertility in all treated rats. This is expected to spark interest in its potential clinical use as a form of male birth control.

PEDs users opinion

S23 is becoming increasingly popular in the bodybuilding community for its powerful muscle building and body composition recomposition effects. Users of PEDs claim that S23 is a more powerful alternative to S4 without the side effect associated with vision. S23 has also been shown in studies to reduce prostate size, which is the opposite of a very common negative side effect of anabolic steroids (prostate enlargement). However, these data are commonly misinterpreted as all SARMS prevent prostatic hypertrophy in a dose-dependent manner.

Effects

High efficiency in building muscle mass and strength
Increase in productivity

Side effects

High degree of suppression of own testosterone
There are anecdotal reports of poor sleep and irritability as with trenbolone.

Effect on the liver

There are currently no studies regarding S23 and liver toxicity. While this is the strongest SARM in existence, it should technically be more liver-friendly than YK11 since it doesn’t have as many methylated groups.