S-23 Drug Interactions, Uses, Effectiveness, Safety & More
What is this page for?
First and foremost: how S-23 interacts with medications. The heart of this page is the interaction list — every drug S-23 is known to interact with, and how serious each one is.
But these pages have grown well beyond that into a full monograph — what S-23 is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy
Check S-23 against your medication
Add one medicationDrugs that interact with S-23
0 medications have a known interaction with S-23, graded by severity. Select any drug for the full evidence-based detail.
We don’t currently list any known drug interactions for S-23. This doesn’t guarantee none exist — always confirm with your pharmacist before combining supplements with your medications.
What Severity, Likelihood & Evidence Mean
Severity — How Serious It Can Be
- Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
- Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
- Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
- No known interaction. Checked against our sources with nothing documented — not the same as proven safety.
Likelihood — How Well It’s Documented
- Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
- Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
- Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
- Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Where This Data Comes From
- Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
- Each drug listed above links to the full report for that exact S-23 combination — clinical detail, likelihood, evidence level, and citations.
- Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
S-23: Uses, Safety & Side Effects
S-23 is an experimental, non-prescription synthetic drug called a selective androgen receptor modulator (SARM), not a dietary supplement, herb, or natural product. It has never been approved for human use, has not been proven safe in people, and is banned in sports; we do not recommend using it.
- Part used
- Not applicable; S-23 is a synthetic chemical compound
- Common forms
- Liquid solutions, capsules, and powders sold as 'research chemicals'
- Muscle building
- Fat loss
- Athletic performance enhancement
- Body recomposition
- Investigational male contraceptive (research only)
Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.
S-23 is an unapproved experimental drug with no human safety data and known hormonal risks.
When used orally or parenterally. The U.S. Food and Drug Administration and other regulatory agencies warn that dietary supplements containing selecti...
Read the full pregnancy detailWhen used orally or parenterally. The U.S. Food and Drug Administration and other regulatory agencies warn that dietary supplements containing selecti...
Read the full breastfeeding detailPregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.
Overview
S-23 is not an herb or natural supplement. It is a synthetic chemical known as a selective androgen receptor modulator, or SARM. These compounds were originally created in laboratories to act like testosterone in certain tissues, such as muscle and bone, while affecting other tissues less.
S-23 is sold online, often labeled as a "research chemical" or "not for human consumption." Despite this labeling, some people buy it and use it to try to build muscle, lose fat, or improve athletic performance. It has never been approved by the U.S. Food and Drug Administration (FDA) or any other major regulatory agency for use in people.
Because it is sold outside the normal medicine and supplement systems, products containing S-23 are not tested or guaranteed for purity, strength, or safety. What is on the label may not match what is in the bottle.
How it works
S-23 is designed to bind to androgen receptors, the same docking sites in the body that natural testosterone uses. By activating these receptors in muscle and bone, SARMs like S-23 are intended to promote muscle growth and strength, much like anabolic steroids but in a more targeted way.
In animal research, S-23 has also been shown to lower the body's own hormone signals that drive sperm production, which is why it has been explored as a potential contraceptive.
It is important to understand that these mechanisms come mostly from laboratory and animal studies. How S-23 behaves in the human body, and at what doses, has not been properly established.
Does S-23 work?
How to read these evidence grades
Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.
For S-23, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.
Also studied for 7 conditions — evidence insufficient to rate
Insufficient Reliable Evidence To Rate Athletic performance
Although there is interest in using oral S-23 for athletic performance, there is insufficient reliable information about the clinical effects of S-23 for this purpose.
Insufficient Reliable Evidence To Rate Breast cancer
Although there is interest in using oral S-23 for breast cancer, there is insufficient reliable information about the clinical effects of S-23 for this condition.
Insufficient Reliable Evidence To Rate Cachexia
Although there is interest in using oral S-23 for cachexia, there is insufficient reliable information about the clinical effects of S-23 for this condition.
Insufficient Reliable Evidence To Rate Muscle strength
Although there is interest in using oral S-23 for muscle strength, there is insufficient reliable information about the clinical effects of S-23 for this purpose.
Insufficient Reliable Evidence To Rate Muscular dystrophy
Although there is interest in using oral S-23 for muscular dystrophy, there is insufficient reliable information about the clinical effects of S-23 for this condition.
Insufficient Reliable Evidence To Rate Sarcopenia
Although there is interest in using oral S-23 for sarcopenia, there is insufficient reliable information about the clinical effects of S-23 for this condition.
Insufficient Reliable Evidence To Rate Urinary incontinence
Although there is interest in using oral S-23 for urinary incontinence, there is insufficient reliable information about the clinical effects of S-23 for this condition.
Source & disclaimer. Effectiveness ratings and evidence summaries are provided by Natural Medicines (Therapeutic Research Center) and shown as licensed. Where Natural Medicines hasn’t rated a use, HelloPharmacist’s pharmacists may add their own reviewed rating and evidence (each such entry is labeled). This is educational information, not medical advice — talk with your pharmacist or doctor before starting, stopping, or changing a supplement.
Safety & precautions
S-23 should be considered unsafe for human use. It is an unapproved drug with no completed human safety studies. The FDA has warned that SARMs are linked to serious health risks, including liver damage and increased risk of heart attack and stroke.
Because SARMs act like hormones, they can suppress your body's natural testosterone production, affect cholesterol, and disrupt other hormone systems. Products sold online may also be mislabeled or contaminated with other substances.
Pregnancy: Do not use S-23 if you are pregnant or might become pregnant. Hormone-altering compounds can harm a developing baby. Breastfeeding: Avoid it while breastfeeding, since it is hormonally active and its safety is completely unknown.
Athletes should know that SARMs, including S-23, are banned by the World Anti-Doping Agency (WADA) and can cause a failed drug test.
Side effects
Because S-23 has not been formally tested in people, its full side effect profile is unknown. Based on what is known about SARMs in general, possible effects include:
- Suppressed natural testosterone production
- Reduced sperm count and possible fertility problems
- Changes in cholesterol levels
- Possible liver injury
- Mood changes, acne, or hair loss
- Potential increased risk of heart attack or stroke
Serious harm is possible, and there is no way to predict who will be affected. If you have used S-23 and feel unwell, stop and seek medical care.
Dosing
There is no established or safe dose of S-23 for humans. It has never gone through the clinical testing that would set a safe and effective dose, so any amounts shared online are unverified and potentially dangerous.
We do not provide dosing guidance for S-23 because doing so could imply it is safe to use, which it is not. If you are considering it, please talk with a pharmacist or doctor first about safer, approved options for your goals.
S-23 & Pregnancy
S-23 & Breastfeeding
© 2026 Therapeutic Research Center
Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center
References & further reading
The 1 references that drive our S-23 monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.
- Joseph JF, Parr MK. Synthetic androgens as designer supplements. Curr Neuropharmacol. 2015;13(1):89-100. PubMed
This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.
Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC
Brands that make products with S-23
3 brands in our database make a supplement containing S-23.
Supplement products with S-23
5 products in our database contain S-23. Open any to see its full ingredient list and every drug interaction we check.
S-23: Common Questions
What is S-23 used for, and does it work?
Does S-23 interact with prescription medications?
How are S-23 interactions rated?
Is it safe to take S-23 with my medications?
Where does this S-23 interaction information come from?
Is S-23 a natural supplement or herb?
Is S-23 legal and approved?
Is S-23 safe to take for building muscle?
Can S-23 affect fertility?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Products that contain S-23
A rotating sample of real supplements in our database that list S-23 — open any to see its full ingredients and every drug interaction we check.
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