Briefly about Mastorine (S23)
Mastorine, also known as S23 , is considered one of the most powerful SARMs available for building lean muscle mass and increasing strength . It provides an extremely hard, lean, and veiny appearance , making it highly sought after in advanced body recomposition phases.
Compared to other SARMs, Mastorine (S23) does, however, exhibit the highest level of testosterone suppression , making it suitable only for experienced and knowledgeable users.

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What is Mastorine (S23)

S23 is a next-generation SARM developed from the structure of an older compound, C-6, which was considered less effective. The main chemical modification consists of replacing the para-nitro group at C-6 with a cyano group.
This change has led to a huge improvement in pharmacokinetics: while C-6 showed an oral bioavailability of approximately 76%, Mastorine (S23) achieves up to 96% oral bioavailability , making it extremely effective even at low doses. For related guidance, see Myostan 5mg – YK11 – SARMS.

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Research

Mastorine (S23) is currently in preclinical development and has been studied exclusively in animal models.
Research has shown that S23 is the most suppressive SARM ever tested , inducing complete infertility in treated rats. For this reason, it is of scientific interest as a potential male hormonal contraceptive .
To date, there are no clinical studies in humans.

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PEDs User Opinions

In the bodybuilding world, Mastorine (S23) is increasingly popular for its extremely powerful effects on muscle mass and definition .
Many users consider it a more powerful version of Andarine (S4) , without the latter’s typical visual side effects
. Some studies indicate a possible reduction in prostate size, but this effect is common to many SARMs and is dose-dependent , therefore often misunderstood.

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Main effects

• Extremely effective in building lean muscle mass

• Significant increase in strength and performance

• Dry, dense and highly defined physical appearance

• Improved productivity and workout intensity

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Side effects

• Very marked suppression of endogenous testosterone

• Anecdotal reports of insomnia, irritability, and nervousness , similar to those seen with trenbolone

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Effect on the liver

There are currently no specific studies on the. For related guidance, see Allaes Testolone 10mg (RAD-140). hepatotoxicity of Mastorine (S23) .
Despite being the most potent SARM, from a chemical point of view it should be less burdensome on the liver than YK-11 , as it has a lower number of methylated groups.

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Testosterone suppression

Mastorine (S23) is widely considered the most testosterone-suppressing SARM currently available.
Its use therefore requires very careful planning and appropriate support strategies.

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Profile

• Half-life: approximately 12 hours

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Dosage

• Beginners: 10 mg daily

• Average dosage: 15–30 mg per day

• Recommended maximum: 50 mg per day

• Women: 5–10 mg daily