Guide to S23 SARM: Uses, Benefits, and Side Effects

Explore the forefront of selective androgen receptor modulator (SARM) research with S23 — a compound under investigation for its high binding affinity and tissue-selective activity. S23 is of particular interest in laboratory settings due to its potential role in modulating anabolic and androgenic pathways in non-clinical models.

Initial findings from preclinical studies suggest that S23 may influence lean tissue development, performance markers, and body composition metrics, all within controlled experimental systems. Its receptor selectivity has also prompted interest in reducing off-target androgenic effects in animal models.

This research-focused guide provides an overview of S23’s structure, investigational uses, dosing protocols in lab models, and known limitations or risks — offering a comprehensive resource for scientists studying androgen receptor modulation.

What is S23 SARM?

S23 is a synthetically engineered SARM structurally derived from the compound C-6. The chemical alteration involves the replacement of the para-nitro group in C-6 with a cyano group, which significantly increases receptor binding affinity and oral bioavailability.

In preclinical research models, S23 demonstrates up to 96% oral bioavailability and a Ki of approximately 1.7 nM, making it one of the most receptor-selective SARMs studied to date. Its full agonist behavior at androgen receptors has also made it a candidate for studies involving androgen suppression and recovery.

BUY S23 SARM

Historical Background of S23

S23 was initially developed in pharmaceutical research pipelines aimed at discovering agents that could mimic anabolic pathways without interacting significantly with non-target tissues. The compound was not designed for therapeutic deployment but for mechanistic studies related to androgen signaling.

Research has explored its capacity to modulate protein synthesis pathways, bone integrity, and hypothalamic-pituitary-gonadal axis feedback in animal subjects. It has also appeared in studies examining the effects of androgen receptor modulation on reproductive hormone regulation in controlled settings.

How Does S23 SARM Work?

S23 binds selectively to androgen receptors (AR) in skeletal tissue and bone matrices, where it can influence the transcription of AR-regulated genes. These pathways are commonly associated with the synthesis of structural proteins and cellular differentiation in non-reproductive tissues.

Unlike non-selective androgens, S23’s structure allows for differential expression and activity, depending on the tissue type. This has led to its inclusion in models assessing the impact of selective AR modulation on physiological and biochemical markers without significant prostate or hepatic activity.  

Uses of S23 SARM

S23 is frequently utilized in preclinical and investigational research due to its selective androgen receptor activity. Below are some of the primary areas of scientific interest:

• Mechanistic Studies on Androgen-Responsive Pathways: S23 is used to explore molecular mechanisms involved in muscle tissue regulation and cellular proliferation in experimental models, including studies related to muscle catabolism and abnormal cell growth.
• Endocrine Suppression Models: Researchers have examined S23 for its impact on the hypothalamic-pituitary-gonadal (HPG) axis in male animal models, particularly its role in suppressing luteinizing hormone (LH), follicle-stimulating hormone (FSH), and endogenous testosterone.
• Exploration of Anabolic-to-Androgenic Ratio Effects: S23 is also studied for its potential to influence biomarkers associated with lean tissue development, adipose modulation, and skeletal density in non-human models, offering insights into tissue-selective anabolic processes.

Investigational Research Applications

Current studies have identified several areas of interest related to S23’s activity in experimental models. Key observed effects include:

1. Modulation of Skeletal Muscle-Associated Biomarkers

S23 is often evaluated in rodent models for its effect on the regulation of proteins involved in skeletal tissue mass balance, including myogenic regulatory factors. In these studies, researchers assess gene expression and protein turnover rates following S23 administration. [1]

2. Study of Adipose Tissue Regulation

Animal models have been used to study whether S23 influences adipocyte signaling pathways and basal metabolic markers. Preliminary data suggest potential for modifying energy expenditure and lipid metabolism, though these results remain inconclusive and model-specific. [2]

3. Reproductive Axis Suppression Studies

S23 has demonstrated dose-dependent suppression of LH, FSH, and testosterone levels in male rodent models. This has prompted its use in exploring feedback inhibition and the reversibility of hormonal suppression, particularly in non-steroidal male contraceptive research frameworks. [3]

4. Bone Health 

Preclinical research indicates that S23 may affect osteoblastic activity and bone mineral content. These effects are currently being explored in animal models related to skeletal turnover and mineral homeostasis. [3]

Research Use Only: S23 is a chemical compound under investigation and is not approved for human consumption. It is intended solely for in vitro and animal model research. This information is for educational purposes within regulated scientific research contexts.

Results of S23 SARM

Studies using animal subjects have reported:

• Tissue Mass Index Shifts: Increases in total skeletal tissue mass in response to S23 exposure under protein-regulated dietary controls.
• Endocrine Response: Suppression of endogenous androgen levels with corresponding hormonal shifts, observed via serum assays.
• Changes in Body Composition Metrics: Reduced adipose volume in models using dual-energy X-ray absorptiometry (DEXA) analysis.

S23 SARM Side Effects

S23 has shown several dose-dependent effects in test systems, including:

• Downregulation of endogenous androgen production
• Altered liver enzyme profiles
• Behavioral agitation in rodent models (e.g., increased locomotor activity)
• Gastrointestinal discomfort indicators
• Increased core body temperature and night-time activity

These effects underscore the importance of rigorous monitoring and adherence to ethical protocols during experimental use.

Post-Exposure Protocols in Research

Due to S23’s suppressive effects on the hypothalamic-pituitary-gonadal axis in animal studies, post-administration protocols are often implemented. One commonly studied agent is Clomiphene Citrate (Clomid), which has shown effectiveness in reactivating endogenous hormone levels in rat models during a 4-week recovery period.

This supports the need for hormone monitoring in longitudinal research designs using S23.

Conclusion 

S23 is a potent investigational SARM under active exploration for its effects on tissue-specific androgen signaling pathways. With strong AR-binding affinity, oral bioavailability, and selective activity in preclinical systems, it continues to be a valuable tool for non-clinical studies on molecular and physiological endpoints. However, S23 is not approved for human use and should never be used outside of regulated laboratory settings. It must be handled by qualified researchers in accordance with institutional, ethical, and legal guidelines.

FAQs

Is S23 approved for human use or treatment?

No. S23 is a research chemical intended only for laboratory use in non-human subjects.

What is the half-life of S23 in test models?

In preclinical models, S23 has demonstrated an approximate half-life of 12 hours, facilitating twice-daily dosing in pharmacokinetic studies.

Can S23 affect hormone levels in animal subjects?

Yes. S23 has been shown to suppress testosterone and related reproductive hormones in rodent models.

Where can S23 be sourced for research?

Qualified institutions may source S23 from research chemical suppliers such as Behemoth Labz, which provides compounds for laboratory and investigational use only.

Does S23 increase tissue mass in laboratory animals?

In specific models, S23 has been associated with measurable increases in skeletal tissue mass and bone density markers. These findings are species-specific and not translatable to humans.

References 

1. Thevis, Mario, et al. “Characterization of in vitro generated metabolites of the selective androgen receptor modulators S‐22 and S‐23 and in vivo comparison to post‐administration canine urine specimens.” Drug testing and analysis 2.11‐12 (2010): 589-598.
2. Cutler, Charlotte, et al. “Detection of the selective androgen receptor modulator S‐23 and its metabolites in equine urine and plasma following oral administration.” Drug Testing and Analysis (2024).
3. Machek, Steven B., et al. “Considerations, possible contraindications, and potential mechanisms for deleterious effect in recreational and athletic use of selective androgen receptor modulators (SARMs) in lieu of anabolic androgenic steroids: A narrative review.” Steroids 164 (2020): 108753.