What are Selective Androgen Receptor Modulators (SARMs)?
Selective Androgen Receptor Modulators (SARMs) are a class of drugs that bind to androgen receptors in the body. They function as either agonists (activate the receptor) or antagonists (prevent the receptor from activating) of these receptors, depending on the tissue they interact with [1].
The principal benefit of SARMs over conventional androgen (steroid) therapy lies in the fact that SARMs are selective to their target receptor, providing the anabolic benefit without the adverse effects associated with traditional, non-selective androgen steroid therapies [1, 2].
It is imporant to unerstand that SARMs are not steroids, however they do exert anabolic effects to the tissue which they target, which is typically either bone or skeletal muscle. However, they have less of an effect on the prostate and other secondary sexual organs [2, 3]. This can be achieved with drug design, as the receptors vary across tissues [1].
Medically, SARMs have been studied for therapeutic application to replace conventional androgen therapy. They pose a promising therapeutic modality for conditions such as:
- osteoporosis,
- Alzheimer's disease,
- breast cancer,
- prostate cancer and benign prostatic hyperplasia,
- hypogonadism,
- muscular dystrophy and muscle wasting,
- and potential roles in male contraception [1, 2, 4, 5].
However, it is important to note that while these are being investigated in pre-clinical and early clinical studies, there are currently no SARM therapies approved by the FDA [1]. Further research is needed to establish a robust safety profile and bring SARMs to clinical practice.
What is S-23 and what are its benefits and side effects?
S-23 is a selective androgen receptor modulator (SARM) that has been investigated for potential use as a male hormonal contraceptive and for its anabolic effects.
The contraceptive action of S-23 has been robustly established in a study on rats [6]. Treatment with S-23 significantly suppressed levels of the lutenising hormone, leading to suppression of speramatogenesis, and, thus, infertility. Notably, this was reversible after 100 days of end of treatment [6].
S-23 also has potent anabolic properties. It was associated with increase of muscle mass in rats [6], and there have been reports of S-23 use as a performance-enhancement drug in humans and horses [7].
Recently, S-23 became available online as a supplement, marketed to enhance muscle mass and athletic performance. However, it is important to note that the safety profile of S-23 is not robustly established, and that its distribution and use is banned by some governments, and regulatory authorities in certain jurisdictions.
There simply is not enough available evidence to conclude what are the benefits and risks of S-23. The rat study [6] does not mention any serious adverse effects, however, these were not the focus of the investigation. In conclusion, while S-23 has contraceptive and anabolic properties, it requires further research and should not be obtained illegally.