Counterfeit S23: what laboratory testing reveals

S23 was never a registered medicinal product. It is marketed as "research chemistry" and all the purchaser knows about the contents of the vial or capsule he knows only from the label. The editors have collected data from independent laboratory analyzes of marketed SARMs and explain what they mean for products labeled "S23".

Why the S23 is an easy target for counterfeiters

S23 is a nonsteroidal selective androgen receptor modulator that was described by a group of researchers at the University of Tennessee in the late 2000s. A major published paper (Jones et al., 2009) considered it as a candidate for hormonal male contraception: in rats, the compound inhibited spermatogenesis while maintaining muscle and bone tissue. It never got to clinical trials on humans.

The absence of a registered drug means the absence of a pharmacopoeial standard, approved production technology, and state quality control. Everything sold under the name S23 is synthesized by unknown manufacturers, often without compliance with Good Manufacturing Practices (GMP). For such products, no one checks either the purity of the substance or the accuracy of the dosage.

The second reason is the high price and "reputation". S23 is touted on the forums as one of the strongest SARMs, which is why it sells for more than the more common compounds. This creates an economic incentive to replace an expensive substance with a cheaper one, dilute it or sell a completely empty product.

The third reason is the impossibility of testing in domestic conditions. A white powder, clear solution or capsule looks the same regardless of the content. The consumer has no tool other than trust in the seller, and the seller, in turn, often does not know what exactly he bought from the intermediary.

What laboratories found in "SARM" products

The most well-known independent analysis of marketed SARMs was published in 2017 in the journal JAMA (Van Wagoner et al.). The researchers purchased 44 products marketed as SARMs online and tested them using liquid chromatography mass spectrometry. Although the work covered various compounds rather than S23 alone, its findings apply to the entire segment of "research chemistry."

Only about half of the products (52%) contained at least one SARM at all. Almost 40% of the samples were found to contain other unregistered pharmacological substances that were not always indicated on the label. The amount of the active substance often differed significantly from the declared amount, and in some products there was no active compound at all.

Anti-doping control laboratories describe a similar picture. Reviews by the group of Mario Tevis (Thevis, Schänzer) regularly report the discovery of off-label substances in products from the "black market", as well as the emergence of new, undocumented SARM analogues. For an athlete, this means that a compound may enter the body that he is not even aware of.

It is important to understand the limitations of these data: samples are small, the market changes rapidly, and individual brands may perform better or worse than the average. However, no study has shown that the products of this segment consistently meet the label. Therefore, the presumption of quality does not apply here.

Typical Non-Labeling Scenarios

Several recurring scenarios can be identified based on the publications. They are not mutually exclusive: one product can be undosed and contain a foreign substance at the same time.

Separately, it is worth saying about liquid forms. Many "research" SARMs are sold as solutions in polyethylene glycol or alcohol. No one has systematically investigated the stability of S23 in such solutions under different storage conditions, so even a properly manufactured product may lose activity or accumulate degradation products.

Another problem is cross-contamination. If different substances are packaged on the same equipment without proper cleaning, traces of other compounds may enter the product. It may be imperceptible to an ordinary consumer, but for an athlete, even a trace amount of a prohibited substance can result in a positive doping test.

Finally, the labels themselves often contain warning signs: the wording "not for human consumption", the absence of the manufacturer's address, batch number and expiration date, advertising promises of "dry mass without side effects".

How the composition is analysed and why the "eye test" does not work

Professional verification of SARM composition is based on chromatographic methods combined with mass spectrometry. Liquid chromatography separates the mixture into individual components, and the mass spectrometer identifies each of them by mass and characteristic molecular fragments. A certified reference standard of the substance is required for accurate quantification.

The main trap of "certificates of analysis" that sellers add to their products is related to reference standards. The document may be issued for a different batch, for a substance, and not for a finished product, or it may be forged in general. Without the ability to verify the laboratory and associate the certificate with a specific batch, it is of limited value.

• Color, smell and taste do not allow to distinguish S23 from another substance.
• Feelings after taking are an unreliable criterion: they can be a placebo effect or the action of a completely different compound.
• Home rapid tests for SARMs do not have validated methods.
• The seller's certificate without independent verification does not confirm the contents of a specific package.

Independent testing by an individual consumer is expensive and does not solve a systemic problem: the result concerns only one sample. That is why medical and anti-doping organizations advise not to rely on "verified sellers", but to refrain from such products in general.

In regulated pharmaceuticals, quality is ensured not by a single test, but by a system: raw material control, process validation, stability studies and inspections. None of this exists for S23, and no single analysis closes the gap.

Implications for health and doping control

Even "pure" S23 has serious known and unknown risks. In preclinical studies, it clearly suppressed the production of gonadotropins and spermatogenesis - that is why it was considered as a contraceptive. Added to this are the risks specific to the SARM class: lowering of HDL, reports of drug-induced liver damage when using marketed products.

Counterfeiting multiplies these risks with uncertainty. A person does not know the dose, does not know what substance he is taking, and therefore, in case of complications, the doctor cannot quickly establish the cause. Cases of liver damage due to SARMs described in the literature often relate to products with untested ingredients.

For athletes, the situation is even tougher. SARMs belong to class S1.2 "Other Anabolic Agents" of the WADA Prohibited List and are permanently prohibited, both in-competition and out-of-competition. The principle of strict liability means that the argument "I did not know what was in the product" does not exempt from sanctions.

The US Food and Drug Administration (FDA) separately warned consumers in 2017 about the dangers of SARM products marketed for bodybuilding, citing liver, heart and stroke risks. These warnings apply to the entire class, in particular products positioned as S23.

Editorial conclusions

S23 is an experimental compound with no registered dosage forms, so anything sold under this name comes from the unregulated market. Independent analyzes of SARM products show that label compliance is the exception rather than the rule.

The most frequent problems are lack of active substance, inaccurate dosage, substitution with other compounds and impurities. No seller's certificate and no subjective feeling guarantee the safety of a particular package.

For athletes, any product with S23 means a direct threat of disqualification, and for everyone else - a risk to the reproductive system and liver, multiplied by an unknown composition.

If you are interested in the topic, please read our articles "S23 Myths", "ACP-105 Counterfeit: What Lab Tests Show on Market Products" and an overview of how WADA regulates SARMs.

List of used literature

1. 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.
2. 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.
3. Thevis M, Schänzer W. Detection of SARMs in doping control analysis. Mol Cell Endocrinol. 2018;464:34–45.
4. Narayanan R, Coss CC, Dalton JT. Development of selective androgen receptor modulators (SARMs). Mol Cell Endocrinol. 2018;465:134–142.
5. World Anti-Doping Agency. The World Anti-Doping Code: International Standard — Prohibited List. Montreal: WADA; чинна редакція.
6. U.S. Food and Drug Administration. FDA warns against using SARMs in body-building products. Consumer update; 2017.