S23 SARM

S23 is a selective androgen receptor modulator (SARM) developed as a potential male hormonal contraceptive and for research into muscle-wasting conditions. As a non-steroidal SARM, S23 binds to androgen receptors with high affinity, producing tissue-selective anabolic effects that have made it a compound of significant interest in androgen receptor research.

S23 is known for its potent binding affinity and strong selectivity for muscle and bone tissue over other androgen-responsive tissues. This selectivity profile makes it particularly valuable for studying androgen receptor mechanisms and tissue-specific responses to androgenic signaling.

S23 Name and Classification

S23 is identified primarily by its research designation and belongs to the class of selective androgen receptor modulators. Unlike anabolic steroids, SARMs like S23 are designed to selectively activate androgen receptors in specific tissues while minimizing activity in others.

S23 was originally developed by GTx Inc. as part of a broader program investigating SARMs for various therapeutic applications, including male contraception and muscle preservation.

Mechanism of Action

S23 functions by binding to androgen receptors with high affinity, particularly in muscle and bone tissue. This selective activation triggers anabolic processes similar to those produced by testosterone, but with greater tissue selectivity.

Key mechanistic features include:

• High androgen receptor binding affinity among investigated SARMs
• Preferential activity in skeletal muscle and bone
• Dose-dependent suppression of natural testosterone production
• Non-aromatizing properties—does not convert to estrogen

In experimental models, S23 demonstrates the ability to stimulate muscle protein synthesis and enhance nitrogen retention while producing minimal activity in prostate tissue compared to traditional androgens.

Benefits in Research

In preclinical research settings, S23 has been studied for its effects on muscle, bone, and reproductive tissues. Published animal studies suggest that S23 may:

• Increase lean muscle mass and promote anabolic signaling in skeletal muscle
• Enhance bone mineral density through androgen receptor activation
• Reduce body fat percentage through metabolic effects on adipose tissue
• Produce dose-dependent androgenic effects useful for studying androgen receptor biology
• Demonstrate contraceptive potential through suppression of spermatogenesis

These findings from controlled experimental models help researchers understand tissue-selective androgen receptor activation and the role of androgens in muscle, bone, and reproductive physiology.

S23 Dosage in Experimental Studies

Most available data on S23 dosage comes from controlled animal research. Published studies report varying protocols depending on research objectives.

Typical experimental dosing ranges:

• 0.1-3 mg/kg administered once daily in rodent models
• Low-dose protocols (0.1-0.5 mg/kg) for studying selective tissue effects
• Medium-dose protocols (1 mg/kg) for evaluating anabolic and androgenic balance
• High-dose protocols (3 mg/kg) for maximum effect assessment and contraceptive research

Dosing considerations in research:

• Oral administration is standard due to good bioavailability
• Once-daily dosing appears sufficient based on reported half-life characteristics
• Duration of administration varies from acute (single dose) to chronic (8-12 weeks)
• Higher doses produce more pronounced suppression of endogenous testosterone

The S23 dosage used in research directly impacts the degree of anabolic effects, androgenic suppression, and overall physiological response, making dose selection a critical component of experimental design.

S23 Side Effects in Research Models

Because S23 is a potent androgen receptor agonist, S23 side effects observed in research depend strongly on dosage and duration. In animal models, researchers monitor for:

Androgenic and hormonal effects:

• Testosterone suppression—dose-dependent reduction in endogenous testosterone production
• Changes in sex hormone levels, including alterations in LH and FSH
• Testicular atrophy at higher doses due to hormonal feedback suppression

Physical and metabolic observations:

• Aggressive behavior patterns noted in some animal studies at higher doses
• Altered lipid profiles, including changes in cholesterol and triglyceride levels
• Liver enzyme fluctuations with transient elevations in hepatic markers
• Prostate tissue changes, though reduced compared to traditional steroids

Tissue-specific effects:

• Desired anabolic changes in muscle and bone tissue
• Changes in body composition reflecting androgenic activity

Understanding these S23 side effects helps researchers establish safe dosing parameters and characterize the full pharmacological profile of the compound in experimental settings.

S23 and Fertility Research

One of the unique research applications of S23 involves S23 fertility studies. Because of its potent suppressive effects on the hypothalamic-pituitary-gonadal axis, S23 has been investigated as a potential male contraceptive agent.

S23 Contraceptive mechanism:

• Suppression of luteinizing hormone (LH) and follicle-stimulating hormone (FSH)
• Dose-dependent reduction in spermatogenesis
• Reversible suppression of sperm production in animal models

Key observations

• Complete suppression of sperm production achieved at higher doses (3 mg/kg) in rodent studies
• Sperm production and fertility restored after cessation of treatment
• Fertility parameters return to baseline within weeks to months post-treatment
• Libido effects appear minimal, unlike some hormonal contraceptives

The S23 fertility suppression profile makes it valuable for studying mechanisms of hormonal contraception in males, androgen receptor's role in spermatogenesis regulation, and reversible suppression of reproductive function. These findings are based on animal models, and applicability to human fertility regulation remains an area of ongoing investigation.

Oral Administration in Research

S23 demonstrates good oral bioavailability in animal studies, making oral administration the standard route in most experimental protocols. This allows researchers to examine sustained systemic effects over extended study periods, maintain consistent daily dosing with minimal stress to subjects, and evaluate dose-response relationships using practical administration methods.

The oral route also facilitates investigation of S23's pharmacokinetic properties, including absorption, distribution, and elimination characteristics.

Human Clinical Trials

Currently, S23 has not advanced to human clinical trials for any indication. All available data comes from preclinical animal research. While the compound shows promising tissue selectivity and potent anabolic effects in experimental models, human safety and efficacy data do not exist.

Why You Should Buy S23 from Sarmful

If you are looking to buy S23 for research purposes, Sarmful offers S23 for sale in liquid form, prepared to support consistent and reliable experimental work.

When you buy S23 from Sarmful, you benefit from:

• Third-party lab testing and in-house verification for purity and concentration
• EU and US domestic shipping for reliable delivery to your research facility
• Convenient payment methods designed for seamless research procurement
• Research-grade quality formulated to meet the standards of serious laboratory work

S23 is available for sale exclusively for legitimate research applications. All products are intended for in vitro research and laboratory experimentation only, not for human consumption or personal use.

S23 SARM – Research Data

Androgen Receptor Activity and Tissue Selectivity

Foundational research published in Endocrinology (2009) characterized S23's binding profile and demonstrated high-affinity androgen receptor binding (Ki ≈ 1.7 nM). The study showed dose-dependent increases in lean muscle mass and bone mineral density in animal models, with S23 producing greater anabolic potency than earlier-generation SARMs while maintaining reduced prostate tissue activity compared to traditional androgens.

Male Contraceptive and Fertility Research

One of the most distinctive areas of S23 research involves male contraceptive studies. A pivotal study in Biology of Reproduction (2009) reported that S23 produced complete, reversible suppression of spermatogenesis in male rats at 3 mg/kg daily dosing. Fertility fully recovered within 100 days after treatment cessation, with maintained libido throughout the study period. The mechanism involves potent suppression of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), making S23 valuable for studying hormonal regulation of male fertility.

Hormonal Suppression and Body Composition

Multiple studies have documented S23's strong suppressive effects on the hypothalamic-pituitary-testicular axis (HPTA). Research shows dose-dependent reductions in endogenous testosterone, LH, and FSH levels, with testicular atrophy observed at higher doses. Body composition studies consistently report significant reductions in body fat percentage, preservation of lean mass during caloric restriction, and alterations in lipid profiles. These findings position S23 among the more potent and suppressive SARMs studied to date.

Human Clinical Trial Status

At this time, S23 has not advanced to human clinical trials. All available data comes from preclinical animal research. While the compound demonstrates potent tissue-selective effects in experimental models, human safety, efficacy, and pharmacokinetic data do not exist.