SARMs & Related Compounds
Ostarine
MK-2866 · Enobosarm · GTx-024
What it is
Ostarine is the most widely studied SARM (Selective Androgen Receptor Modulator). Originally developed by GTx Inc. for muscle wasting in cancer patients. Made it through Phase 3 trials but didn't get FDA approval. Considered the "starter" SARM — mild gains, mild suppression, joint healing properties.
How it works
Selectively binds androgen receptors in muscle and bone tissue without significantly activating receptors in the prostate, hair follicles, or other tissues that respond to traditional anabolic steroids. This selectivity is theoretical — in practice, suppression of natural testosterone still happens.
Benefits
- 5–10 lbs of lean muscle gain over 8–12 weeks (typical user)
- Joint healing (often-reported benefit)
- Strength gains
- Body recomposition (some fat loss with muscle gain)
- Mild compared to traditional anabolics
Timeline
- Week 1–2
- Joint pain reduction; subtle strength gains.
- Week 4–6
- Visible muscle gains; better recovery.
- Week 8–12
- Peak gains; cycle off mandatory.
Dosing & titration
Beginner dose10–15 mg orally daily
Standard dose20–25 mg orally daily
Cycle length8–12 weeks ON, then 4–8 weeks OFF (with PCT)
When to titrate upMost users do well at 20–25 mg. Above 30 mg, suppression worsens without proportional gains.
Side effects & risks
- Testosterone suppression (mild but real)
- Slight HDL reduction
- Liver enzyme elevation in some users
- Possible vision changes (rare, more common with Andarine)
- PCT typically required after cycle
Get baseline blood work. Test, LH, FSH, estradiol, lipids, liver enzymes. Re-test post-cycle. Banned in WADA-tested sports. Not FDA-approved.
Typical price
$60–$120/moFrom research suppliers. Quality varies wildly — third-party tested products are essential.
Studies
- Dalton JT et al. The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women — Phase 2 trial. PubMedJournal of Cachexia, Sarcopenia and Muscle, 2011
- Crawford J et al. Study Design of POWER1 and POWER2 trials of enobosarm in non-small cell lung cancer cachexia — Phase 3 design. PubMedCurrent Oncology Reports, 2016
- Search PubMed for ostarine / enobosarm — PubMed searchLive PubMed search
Educational reference only. Not medical advice. Not FDA-approved.