S23 Interactions: Alcohol, Caffeine, Food and Other Compounds

Questions about combining a compound with alcohol, coffee, meals, fasting windows or other substances are questions about interaction data. Interaction data comes from a specific kind of study: co-administration in animals or humans with measurement of blood levels, enzyme activity, or clinical endpoints. For S23, no such study was located in the verified literature underpinning this page. That absence is the central finding, and it is more informative than speculation.

This page is for educational purposes only and is not medical advice; consult a licensed physician about any question involving health, medication, or an investigational compound. Nothing here describes what anyone should do, and no combination described below is characterised as safe, unsafe, advisable or inadvisable — only as studied or unstudied.

What "Interaction" Means in the Published Record

Researchers use the word interaction in at least three distinct senses, and conflating them is the most common error in non-specialist writing about compounds like S23.

• Pharmacokinetic interaction — one substance changes how much of another reaches circulation, usually through absorption, plasma protein binding, hepatic enzyme induction or inhibition, or renal clearance. Demonstrating this requires blood sampling over time in the presence and absence of the second substance.
• Pharmacodynamic interaction — two substances act on the same receptor, pathway or organ system, producing additive, synergistic or opposing effects even when neither changes the other's blood concentration.
• Molecular interaction — a physical binding relationship between two molecules, often characterised computationally before any biological testing. Work of this type was illustrated by researchers who applied bioinformatics approaches to snake venom KTS/disintegrin–integrin binding relationships (PMID 36615520), and by a protein–protein interaction network analysis built from nuclear proteomics data in dehydration-stressed Xerophyta schlechteri leaves (PMID 36969388). Neither study involved S23 or any selective androgen receptor modulator; they are cited here only to show what a molecular interaction paper looks like.

A search result promising "S23 and alcohol" is asking for the first two categories. The literature currently supplies neither.

What the Indexed Literature Actually Contains About S23

The analytical chemistry record

The most directly relevant paper is analytical rather than clinical. Researchers developed a multi-residue high-throughput UHPLC-MS/MS method for routine monitoring of SARM compounds in equine and bovine blood, describing the method as intended for routine screening applications (PMID 32519780). That study characterised detection methodology in animal blood matrices; it did not administer any SARM to a person, did not co-administer any second substance, and reported no efficacy or toxicity endpoints. Its relevance to interaction questions is indirect but real: residue-monitoring methods are how regulators and laboratories establish whether a compound is present in a sample at all, which is the prerequisite for any future co-exposure study.

The naming-collision problem

Literature searches for "S23" retrieve a substantial body of work on an entirely different entity: ribosomal protein S23. Researchers identified and functionally characterised ribosomal protein S23 as a new member of the antimicrobial protein family in a developmental and comparative immunology study (PMID 32423862). The string "S23" also appears in unrelated surgical anatomy, as in the report of indocyanine green fluorescence image-guided laparoscopic anatomical S2/3 liver resection using the TICGL technique (PMID 38087110). Anyone assembling an evidence base on the SARM-class compound must filter these out; failing to do so produces apparent "S23 research" that has nothing to do with androgen receptor pharmacology.

S23 and Alcohol

Evidence status: no co-administration study identified. No trial, animal study or case series in the verified set examined ethanol together with S23, measured blood concentrations of either substance in the presence of the other, or reported clinical outcomes from combined exposure.

The alcohol-related paper in the indexed set is a food-science investigation: researchers examined electrostatic fermentation and reported molecular response insights relevant to tailored beer production (PMID 38397576). That study concerned fermentation biology and beverage manufacturing, not human co-exposure with any pharmaceutical or investigational agent, and it cannot be read as saying anything about S23.

Mechanistic reasoning (labeled as reasoning, not findings)

When no co-administration data exists, pharmacologists reason from shared organ systems rather than from evidence. Ethanol is metabolised hepatically and is a well-recognised source of hepatic stress in the general medical literature; orally administered small molecules are also subject to first-pass hepatic metabolism. Researchers would therefore predict that the liver is the plausible site of any interaction and would design a study around hepatic enzyme activity and serum liver markers. That prediction is a hypothesis. It has not been tested for S23, and a hypothesis is not a result.

The methods such a study would likely borrow are illustrated by hepatology work outside the SARM field: a multicenter study reported that sequential use of the Fibrosis-4 index combined with Mac-2 binding protein glycosylation isomer improved detection of advanced fibrosis in metabolic dysfunction-associated steatotic liver disease (PMID 42006192). That study involved no SARM and no alcohol co-exposure protocol; it is referenced solely as an example of the non-invasive marker strategies hepatology researchers now use when they want to quantify liver outcomes.

S23 and Caffeine

Evidence status: no interaction study identified. Nothing in the verified literature examined caffeine alongside S23, in any species, at any exposure level.

Mechanistic reasoning, again labeled as such: caffeine's clearance is dominated by a single hepatic enzyme pathway, which is why caffeine is frequently used as a probe substrate in drug-interaction pharmacology. Researchers investigating a novel compound often run a caffeine probe precisely because the result generalises to other substrates of that pathway. No such probe study has been published for S23 in the verified set, so whether S23 induces, inhibits or ignores the enzymes that clear caffeine is unknown rather than reassuring. Statements circulating online that caffeine "stacks well" or "does not interact" with S23 have no published measurement behind them.

S23 With Food and Fasting

Evidence status: no food-effect study identified. A food-effect study compares systemic exposure after dosing in the fed and fasted states, typically reporting peak concentration and total exposure for each condition. No such comparison was located for S23.

The general reasoning researchers apply: lipophilic small molecules often show altered absorption when co-ingested with dietary fat, and gastric emptying rate changes the time to peak concentration. Whether either applies to S23 is unestablished. The analytical groundwork for answering the question exists in principle — the UHPLC-MS/MS approach developed for SARM residue monitoring in equine and bovine blood demonstrated that class compounds can be quantified in blood matrices (PMID 32519780) — but a detection method is not a pharmacokinetic study, and that paper reported no fed-versus-fasted comparison.

Other Commonly Asked Combinations

Combination questions frequently involve other SARM-class compounds, testosterone or other androgens, aromatase inhibitors, selective estrogen receptor modulators, 5-alpha reductase inhibitors, statins, antidepressants, and over-the-counter liver-support supplements. For every one of these pairings, the verified literature contains no S23 co-administration study. There is no published dataset describing additive receptor occupancy, no reported change in exposure, and no clinical outcome comparison between single-compound and combined exposure.

It is worth noting how an adjuvant or combination study is normally structured, since the design is what is missing here. Researchers characterised helicid as a novel anti-Staphylococcus aureus adjuvant, reporting combination effects against the target organism (PMID 39681184). That is an antimicrobial pharmacology paper with no relationship to S23; it is included to make the point that combination claims normally rest on an explicit combination experiment, and no equivalent experiment has been published for S23 with any of the compounds listed above.

Evidence Status at a Glance

Adverse Events From Combinations: What Studies Report

No published study in the verified set reported adverse events arising from S23 combined with alcohol, caffeine, food, supplements or medicines, because no study administered those combinations. The absence of reported adverse events is therefore an absence of observation, not an observation of absence — a distinction that matters whenever unstudied combinations are discussed.

What the record does contain is infrastructure for future safety work. The analytical study described a high-throughput screening method capable of routine monitoring of SARM compounds in blood (PMID 32519780), and hepatology researchers reported an improved sequential marker strategy for detecting advanced liver fibrosis in a multicenter cohort (PMID 42006192). Tools of that kind are what an eventual co-exposure safety study would deploy. Until such a study is run and published, any claim about combination-related adverse events for S23 is inference rather than data.

How an Interaction Study Would Be Built

1. Validated quantification. A method capable of measuring the compound in the relevant biological matrix, of the type researchers developed for SARM residues in equine and bovine blood (PMID 32519780).
2. Single-agent pharmacokinetics. Baseline exposure curves before any second substance is introduced.
3. Controlled co-administration. A crossover design in which each subject serves as their own control, with fixed timing between the two substances.
4. Mechanistic follow-up. Enzyme phenotyping or in vitro work to explain any observed shift, comparable in spirit to the computational binding analyses researchers applied to disintegrin–integrin pairs (PMID 36615520).
5. Clinical endpoints. Organ-function markers tracked over time, using validated non-invasive panels of the kind reported in multicenter fibrosis detection work (PMID 42006192).

None of these five steps has been completed and published for S23 with alcohol, caffeine or food. Readers evaluating claims found elsewhere can reasonably ask which of these steps the claim rests on.

Limitations of This Page

This page reflects a defined set of verified publications. Regulatory status, laboratory-supply labelling and anti-doping listings change independently of the research literature, and analytical methods such as the multi-residue blood screen for SARM compounds continue to be refined (PMID 32519780). Where this page states that no study exists, that statement describes the verified set rather than every document ever published. Where it describes mechanism, it is describing the reasoning researchers apply in the absence of data, explicitly labeled as such, and not a reported result.

References

• Development of a multi-residue high-throughput UHPLC-MS/MS method for routine monitoring of SARM compounds in equine and bovine blood (Drug Testing and Analysis, 2020)
• Identification and functional characterization of ribosomal protein S23 as a new member of antimicrobial protein (Developmental and Comparative Immunology, 2020)
• Electrostatic Fermentation: Molecular Response Insights for Tailored Beer Production (Foods, 2024)
• Sequential Fibrosis-4 Index and Mac-2 Binding Protein Glycosylation Isomer Combination Improve Detection of Advanced Fibrosis in Metabolic Dysfunction-Associated Steatotic Liver Disease: A Multicenter Study (Gastro Hep Advances, 2026)
• Helicid: A novel Anti-Staphylococcus aureus adjuvant (Biochimie, 2025)
• The First Snake Venom KTS/Disintegrins-Integrin Interactions Using Bioinformatics Approaches (Molecules, 2022)
• Construction and analysis of protein-protein interaction networks based on nuclear proteomics data of the desiccation-tolerant Xerophyta schlechteri leaves subjected to dehydration stress (Communicative & Integrative Biology, 2023)
• Indocyanine green fluorescence image-guided laparoscopic anatomical S2/3 resection using the TICGL technique (Surgical Endoscopy, 2024)