Ostarine Research Reference

Catalog classification, reference sizes, lab math links, and source-backed data. Educational use only — not medical advice.

Researched for: Vendor-neutral scientific reference catalog for PepTools

Nonsteroidal selective androgen receptor modulator (SARM) compound Reference needs_revision Best effort · source review pending

Also known as: Enobosarm, GTx-024, MK-2866, MK2866, S-22, Ostabolic

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Best-effort research profile: this record has not passed full two-source scientific verification. Descriptive fields, research protocols, storage/handling notes, and interaction guidance below are shown with their evidence labels, but calculator presets and exact dosing math remain hidden until the record is verified or reaches Community-Supported status.

Quick Facts

Reference Sizes

Not standardized / source review pending

Best-Effort Research Profile

Ostarine is the common name for enobosarm, a nonsteroidal selective androgen receptor modulator developed as an orally active androgen-receptor agonist. Clinical studies evaluated enobosarm in healthy older adults and in patients with cancer-associated muscle wasting, with reported effects including increases in lean body mass and, in some studies, physical-function measures. It remains an investigational compound and is not an FDA-approved therapeutic product.

Source review pending. This descriptive profile is shown from the available source material as a best-effort educational reference. It has not passed the full verification bar and is not a dosing instruction, medical claim, or treatment recommendation.

Research Profile

Half-Life

Approximately 22 hours has been reported in clinical pharmacokinetic literature; one cited comparison reports a range of approximately 13.7 to 31.3 hours among individuals.

Administration Routes (Research)

oral

Reported Research Effects

Selective androgen-receptor agonist activity reported in preclinical and clinical-development literature.
In a phase II study in healthy older men and postmenopausal women, enobosarm produced dose-dependent increases in total lean body mass, with the 3 mg group showing statistically significant improvement versus placebo.
In a phase II cancer-associated muscle-wasting study, once-daily oral enobosarm at 1 mg and 3 mg was associated with increases in lean body mass over the study period.
Clinical-development studies evaluated physical function, including stair-climb performance, as a potential pharmacodynamic or efficacy outcome.
Clinical studies reported laboratory and tolerability findings requiring monitoring; these findings should not be interpreted as evidence of established safety or efficacy for general use.

Reflects preclinical/research literature context only. Not a medical claim, dosing instruction, or treatment recommendation.

Research Notes

Evidence-backed human study regimens include oral once-daily administration of 1 mg or 3 mg for up to 113 days in a cancer-associated muscle-wasting trial, 1 mg, 3 mg, or 5 mg once daily for 12 weeks in a healthy older-adult phase II study, and 3 mg once daily for 147 days in the planned POWER phase III program. These are historical investigational study protocols, not prescribing or self-administration guidance. Reliable authoritative sources reviewed did not establish a catalog-standard reference size, validated storage condition, or generalizable onset value.

Supplementary research context only. Not medical advice or a treatment recommendation.

Registry Identifiers

IUPAC: (2S)-3-(4-cyanophenoxy)-N-[4-cyano-3-(trifluoromethyl)phenyl]-2-hydroxy-2-methylpropanamide; molecular formula: C19H14F3N3O3; molecular weight: 389.3 g/mol; CAS RN: 841205-47-8; PubChem CID: 11326715; FDA UNII: O3571H3R8N; ChEMBL ID: CHEMBL1738889; InChIKey: JNGVJMBLXIUVRD-SFHVURJKSA-N.

Source-Backed Observations

FDA lists ostarine/enobosarm/MK-2866/GTx-024 among substances covered by its SARM safety communications. Human clinical studies have used oral administration, but studied regimens were investigational and do not establish approved clinical use. Ostarine is included on the World Anti-Doping Agency prohibited list as an anabolic agent.

Reflects published research. Educational reference — not a recommendation for use.

Sources Under Review

Enobosarm Compound Summary, PubChem CID 11326715
https://pubchem.ncbi.nlm.nih.gov/compound/11326715 (accessed 2026-09-03)

Information on Select Dietary Supplement Ingredients and Other Substances
https://www.fda.gov/food/dietary-supplements/information-select-dietary-supplement-ingredients-and-other-substances (accessed 2026-09-03)

The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II trial
https://pmc.ncbi.nlm.nih.gov/articles/PMC3177038/ (accessed 2026-09-03)

Effects of enobosarm on muscle wasting and physical function in patients with cancer: a double-blind, randomised controlled phase 2 trial
https://pmc.ncbi.nlm.nih.gov/articles/PMC4898053/ (accessed 2026-09-03)

Study Design and Rationale for the Phase 3 Clinical Development Program of Enobosarm, a Selective Androgen Receptor Modulator, for the Prevention and Treatment of Muscle Wasting in Cancer Patients
https://pmc.ncbi.nlm.nih.gov/articles/PMC4853438/ (accessed 2026-09-03)

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Research Use Only. All content is for educational and research reference only. Not medical advice, a treatment recommendation, or guidance on human use. Compounds are not FDA-approved drugs unless specifically noted.