Description
S23 powder is 2,000 mg of one of the most potent SARMs ever studied, sealed in a UV-resistant foil pouch. The current batch tested at 99.8% purity.
Buy S23 powder online
It’s part of our SARMs powder range. The pre-dissolved version is liquid S23 at 20 mg/mL. For comparison studies with other high-affinity compounds, look at LGD-4033 powder too.
What is S23 powder?
S23 is a non-steroidal SARM from the University of Tennessee group that also made andarine. In rats it binds the androgen receptor tightly and acts as a full agonist in muscle, with strength that researchers have compared to anabolic steroids.
Rat data puts its oral bioavailability near 96% and its half-life at about 12 hours.
S23 powder in contraception research
S23 is best known from a 2009 study by Jones and colleagues looking at male hormonal contraception. Combined with estradiol benzoate, S23 suppressed sperm production in every male rat tested, and fertility returned within about 100 days of stopping.
The same study found dose-dependent gains in lean mass and bone density and a drop in fat mass. No human trials exist. Read the papers on PubMed.
S23 powder specifications
- Compound: S23
- CAS number: 1010396-29-8
- Formula: C18H13ClF4N2O3
- Molar mass: 416.75 g/mol
- Half-life: About 11.9 hours (rat data)
- Class: Selective androgen receptor modulator
- Amount: 2,000 mg
- Packaging: UV-resistant foil pouch
- Purity: 99.8% (COA 10/17/2025)
- SKU: 21
Measuring and storage
The pouch holds 2,000 mg of dry powder. Measuring tools aren’t included, so you’ll need an analytical balance that reads to at least 1 mg for accurate work. Weigh in a draft-free spot and reseal the pouch straight away.
Most labs dissolve SARM powders in PEG-400. Bringing the full 2,000 mg up to 100 mL with our PEG-400 gives 20 mg/mL, the same strength as our liquid version. Gentle warming and stirring help it dissolve. Store the sealed pouch in a cool, dry place away from light.
Lab testing and certificate of analysis
Our S23 powder is tested by MZ Biolabs, an independent lab in Arizona, and packed in the USA. The current certificate of analysis is dated 10/17/2025 and reports 99.8% purity. If you need the full COA for your lab records, email us and we’ll send it before you order.
S23 powder FAQ
Why is S23 powder considered so strong?
It binds the androgen receptor with high affinity and acted as a full agonist in rat muscle.
Does S23 suppress testosterone?
Yes, strongly in rats. That’s the basis of the contraception research.
How do I prepare an S23 solution?
Weigh the powder and dissolve it in PEG-400.
Why researchers buy from Sports Technology Labs
A 2017 JAMA study bought 44 products sold online as SARMs and tested them. Only 52% contained a SARM at all, and 39% contained other unapproved drugs. That’s the problem we set out to fix. We start with raw material that’s at least 98% pure, bottle everything in the USA and send every batch to MZ Biolabs before it goes on sale. Liquids go into glass bottles with glass droppers, so there’s no plastic in contact with the solution.
Shipping, returns and support
Orders over $149 ship free inside the US, and express shipping is there at checkout if you’re short on time. Everything we sell is covered by a 60-day money-back guarantee. Questions about a batch, a COA or an order? Email us and a real person will answer.
For laboratory research use only
S23 powder is sold for laboratory research only. It isn’t a dietary supplement, it isn’t approved by the FDA, and it isn’t for human or veterinary use. We’re a chemical supplier, not a medical provider, and nothing on this page is medical advice. Please don’t buy it for personal use or sports.
Add S23 powder to your cart, or browse every SARMs powder we carry.
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