S23: claims, myths and missing evidence

A whole mythology has formed around S23: forums call it "the closest thing to SARM steroids without their downsides." The problem is that the scientific body of data on this compound is extremely small. The editors have analysed the most popular claims and compared them with what is actually known from published works.

Where did S23 come from and why is there so little data about it

S23 is a nonsteroidal compound from the group of arylpropionamides, which also includes andarine (S4) and enobosarm (ostarine). It was synthesised and characterized by the group of James Dalton and Duane Miller at the University of Tennessee. A key publication (Jones et al., 2009, Endocrinology) described S23 as a potential hormonal male contraceptive.

All major data on S23 were obtained in rats. The researchers studied how the compound affects prostate weight, the levator ani muscle (a classic marker of anabolic activity in rodents), bone tissue, gonadotropins, and spermatogenesis. There are no controlled clinical studies on humans in the peer-reviewed literature.

This is a fundamental point for understanding all subsequent myths. When on the forum they write about "effective dose", "cycle duration" or "mild side effects", behind this are not clinical data, but personal reports of people who took a product of unknown composition. Such reports cannot replace controlled studies, randomization, and laboratory monitoring.

Extrapolation of data from rats to humans also has limits. Pharmacokinetics, hepatic metabolism, and tissue sensitivity to androgens vary among species. Just because a compound behaved a certain way in rodents does not guarantee the same behaviour in the human body.

Myths about "safety" and selectivity

Myth 1: "SARMs are a safe alternative to steroids." The word "selective" in the class name only means that in preclinical models the compound acted more strongly on muscle and bone than on the prostate. It is not synonymous with security. The selectivity is relative, depends on the dose and does not cover all organs — for example, the liver, lipid metabolism, or the hypothalamic-pituitary axis.

Myth 2: "Because S23 is not a steroid, it does not harm the liver." The absence of the 17-alpha alkyl group, characteristic of hepatotoxic oral steroids, does not imply automatic safety. In the medical literature, a series of drug-induced liver damage against the background of various SARMs has been described (Flores et al., 2020; Mohideen et al., 2023). There is no separate data for S23 - and this is not reassuring, but on the contrary, it means an unknown risk.

Myth 3: "Side effects only occur from overdose." In preclinical studies, a pronounced suppression of gonadotropins in S23 was observed precisely in those doses that produced an anabolic effect. That is, "beneficial" and "harmful" effects are closely related, and not diluted in different dose ranges.

Myth 4: "SARMs do not affect cholesterol." Several SARMs studied in humans (notably LGD-4033 and enobosarm) have been shown to decrease HDL, the “good” cholesterol (Basaria et al., 2013; Dalton et al., 2011). There is no reason to believe that S23 as a potent androgen agonist is an exception.

Myths about hormones and fertility

Myth 5: "S23 does not suppress its own testosterone." This is perhaps the most dangerous myth, because it directly contradicts the purpose with which the S23 was developed. The contraceptive idea was precisely to reduce luteinizing and follicle-stimulating hormones and stop spermatogenesis through a negative feedback loop, while preserving androgenic effects in muscles and bones.

In a study by Jones et al. S23 in rats (in combination with oestradiol benzoate) caused a profound inhibition of spermatogenesis, which was reversible after cessation of administration. Recovery in laboratory animals under controlled conditions does not mean that it will be the same in humans, especially if the product had an unknown composition and duration of administration.

Myth 6: "After the course, everything is restored in just a few weeks." Even for well-studied anabolic steroids, recovery times vary widely, from months to persistent hypogonadism in some individuals (Rahnema et al., 2014). For S23, there is no human recovery data at all, so any promises about timing are guesswork.

Myth 7: "If the libido is normal, then the hormones are normal." Well-being on the background of taking an androgen agonist can be normal even with deeply suppressed own testosterone, because the receptors are stimulated by the compound itself. The real picture appears after withdrawal or in laboratory tests - LH, FSH, total testosterone and semen analysis.

Myths about results, legality and quality

Myth 8: "S23 gives "dry" mass without retaining water and fat." The claim is based on the fact that S23 does not aromatize into oestrogens like testosterone. However, the absence of aromatization does not mean that the compound bypasses all regulatory mechanisms. There is no controlled data on the composition of the human body against the background of S23, so "dry mass" is a marketing formula, not an established fact.

Myth 9: "This is legal research chemistry." Selling with the label "not for human consumption" is a way to circumvent the regulation of medicinal products, not to confirm the legality of the intake. In many countries, SARMs are unregistered and cannot be legally sold as drugs or supplements. In sports, S23, like other SARMs, belongs to class S1.2 of the WADA Prohibited List.

Myth 10: "A reliable seller always has a genuine product." An independent analysis of SARM products from the Internet (Van Wagoner et al., 2017) showed that the composition of a large number of them did not correspond to the label. The "reputation" of the seller on the forum is not a method of quality control.

How to distinguish fact from forum legend

Myths about S23 survive because they are based on real fragments of science taken out of context. "Selectivity" has indeed been described in preclinical studies, "anabolic effect" has indeed been observed in rats. But the conclusion "therefore, it is effective and safe for humans" does not follow from these facts.

The editors suggest some simple questions to ask about any claim about experimental compounds:

1. On whom was the data obtained — on cells, animals or humans?
2. Was the study controlled and published in a peer-reviewed journal?
3. Have you checked the composition of the product referred to in the reviews?
4. Were hormones, lipids, and liver enzymes measured, not just weight and sensation?
5. Who benefits from sharing this claim?

If most of these questions are not answered, the claim remains a hypothesis or an advertisement. For S23, this is exactly the case with almost all practical advice that circulates on the Internet.

It is also worth remembering about the "survivor effect": on the forums, those who got through without any noticeable problems write more often. People dealing with infertility, liver damage, or long-term hypogonadism consult their doctors, not publish "course reports."

Editorial conclusions

Most of the popular ideas about S23 have no scientific basis: the compound has only been studied preclinically, and its main known property is a powerful inhibition of gonadotropins and spermatogenesis.

Lack of clinical data does not mean “zero risks” but unknown risks, compounded by the known problems of the SARM class—lipid effects, reports of liver damage, and poor quality of marketed products.

Critical thinking about sources is the best defense against marketing myths in sports pharmacology.

We also recommend reading our articles "Counterfeit S23: What Lab Tests Show for Marketed Products", "ACP-105: What It Is (SARM) and How It Works" and "Does ACP-105 Suppress Testosterone Production".

List of used literature

1. Jones A, Chen J, Hwang DJ, Miller DD, Dalton JT. Preclinical characterization of a (S)-N-(4-cyano-3-trifluoromethyl-phenyl)-3-(3-fluoro-4-chlorophenoxy)-2-hydroxy-2-methyl-propanamide: a selective androgen receptor modulator for hormonal male contraception. Endocrinology. 2009;150(1):385–395.
2. Basaria S, Collins L, Dillon EL, et al. The safety, pharmacokinetics, and effects of LGD-4033, a novel nonsteroidal oral, selective androgen receptor modulator, in healthy young men. J Gerontol A Biol Sci Med Sci. 2013;68(1):87–95.
3. Dalton JT, Barnette KG, Bohl CE, et al. The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II trial. J Cachexia Sarcopenia Muscle. 2011;2(3):153–161.
4. Flores JE, Chitturi S, Walker S. Drug-induced liver injury by selective androgenic receptor modulators. Hepatol Commun. 2020;4(3):450–452.
5. Van Wagoner RM, Eichner A, Bhasin S, Deuster PA, Eichner D. Chemical composition and labeling of substances marketed as selective androgen receptor modulators and sold via the internet. JAMA. 2017;318(20):2004–2010.
6. Rahnema CD, Lipshultz LI, Crosnoe LE, et al. Anabolic steroid-induced hypogonadism: diagnosis and treatment. Fertil Steril. 2014;101(5):1271–1279.
7. Mohideen H, Hussain H, Dahiya DS, Wehbe H. Selective androgen receptor modulators: an emerging liver toxin. J Clin Transl Hepatol. 2023;11(1):188–196.
8. World Anti-Doping Agency. Prohibited List. Montreal: WADA; чинна редакція.