Description
RU-58841 powder is 2,000 mg of the topical antiandrogen in a UV-resistant foil pouch. Labs use the powder to prepare topical solutions at their own strength, usually in an alcohol-based carrier.
Buy RU-58841 powder online
It’s in our SARMs powder category. If you want a ready solution, liquid RU-58841 is 50 mg/mL with a metered pump. It’s also sold with liquid testolone in the RAD-140 and RU-58841 stack.
What is RU-58841 powder?
RU-58841 is a non-steroidal antiandrogen first made by Roussel Uclaf in the 1980s, also known as PSK-3841 and HMR-3841. It was designed for the skin: it blocks androgen receptors in hair follicles and sebaceous glands while staying mostly out of the bloodstream.
It doesn’t change DHT levels the way finasteride does. It blocks the receptor DHT would bind to.
RU-58841 powder research on hair and skin
In stump-tailed macaques, which lose scalp hair in a pattern much like men, topical RU-58841 improved hair density and thickness. Human scalp grafts on nude mice grew more active follicles when treated with it. Hamster flank organ studies showed strong local antiandrogen effects at microgram doses.
It was also studied for acne and hirsutism. A clinical program was started but never finished, so there’s no approved product. See PubMed for the papers.
RU-58841 powder specifications
- Compound: RU-58841 (PSK-3841)
- CAS number: 154992-24-2
- Formula: C17H18F3N3O3
- Molar mass: 369.3 g/mol
- Class: Androgen receptor antagonist
- Amount: 2,000 mg
- Packaging: UV-resistant foil pouch
- Purity: 99.31% (COA 09/23/2025)
- SKU: 14
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.
Store the sealed pouch in a cool, dry place away from light and moisture.
Lab testing and certificate of analysis
Our RU-58841 powder is tested by MZ Biolabs, an independent lab in Arizona, and packed in the USA. The current certificate of analysis is dated 09/23/2025 and reports 99.31% purity. If you need the full COA for your lab records, email us and we’ll send it before you order.
RU-58841 powder FAQ
What solvent is used for RU-58841 powder?
Topical research solutions are usually made with ethanol, often mixed with propylene glycol or similar carriers.
Is RU-58841 a SARM?
No. It blocks the androgen receptor instead of activating it.
How strong is your liquid version?
Our liquid RU-58841 is 50 mg/mL, and each pump delivers 1/6 mL.
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
RU-58841 powder is supplied strictly for laboratory and analytical research. It is not approved by the FDA, is not a dietary supplement and must not be used in people or animals. Nothing here is medical advice, and we won’t sell it for personal or athletic use.
Order RU-58841 powder now, or see the other SARMs powders in stock.
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