MK-2866 (Ostarine) | 100 x 10 mg

SAFETY DATA SHEET

Ostarine, chemically designated as MK-2866, is a non-steroidal Selective Androgen Receptor Modulator (SARM) developed to prevent and treat muscle wasting and osteoporosis. Its mechanism of action involves high-affinity binding to androgen receptors in skeletal muscle and bone tissues, selectively stimulating anabolic activity without the androgenic effects.

Its tissue-selective profile minimizes undesirable effects on the prostate or other non-target organs. Ostarine does not undergo aromatization to estrogen and exhibits minimal hepatotoxicity, which contributes to its favorable safety profile in short-term research applications.

• Demonstrates anabolic activity in skeletal muscle tissue models, including under conditions lacking mechanical load stimulation
• Modulates bone remodeling pathways, indicating potential utility in preclinical models of reduced bone mineral density (e.g., osteopenia, osteoporosis)
• Exhibits muscle-preserving effects under simulated states of caloric deficit or musculoskeletal disuse, relevant to models of cachexia and immobilization

⚠ Important Note: This product is supplied strictly for laboratory research use only. It is not approved for human consumption or therapeutic use. Not intended to diagnose, treat, cure, or prevent any diseaseOstarine, also known as MK-2866 or Enobosarm, is a Selective Androgen Receptor Modulator (SARM) developed to mimic some effects of testosterone in muscle and bone tissue.

Strictly for laboratory research use only. Not for human consumption.

Ostarine is the most clinically studied compound in the SARM class. Where most selective androgen receptor modulators stalled at early-phase work, ostarine progressed through more than a dozen human trials and into Phase 3 — which means researchers working with it have something rare in this field: a substantial published dataset to compare against.

That makes reference-standard quality non-negotiable. Every batch supplied by Max Muscle Labs is manufactured in the UK and verified to >99% purity by HPLC, with independent analysis before release, so your results can be measured against the literature rather than against an unknown.

Specifications

About the compound

Ostarine is a non-steroidal, orally active selective androgen receptor modulator, developed by GTx, Inc. under the designations MK-2866 and GTx-024, and known clinically as enobosarm. It binds the androgen receptor and acts as an agonist in muscle and bone tissue, with weaker activity in tissues such as the prostate — the tissue selectivity that gives the class its name.

It was originally investigated for muscle-wasting conditions, and has since been studied across cancer cachexia, age-related muscle loss, stress urinary incontinence and androgen-receptor-positive breast cancer. It remains investigational and unapproved in every jurisdiction.

For a full research overview of the compound, see our guide to what ostarine (MK-2866) is and our breakdown of what ostarine does at the cellular level.

What the published research shows

Ostarine’s evidence base is the deepest in the class, and it’s worth knowing both what it demonstrated and where it fell short.

Phase 2, healthy elderly. A 12-week double-blind, placebo-controlled trial in 120 healthy elderly men and postmenopausal women reported increased lean body mass alongside dose-dependent changes in HDL cholesterol and sharp reductions in sex hormone-binding globulin (Dalton et al., 2011).

Phase 3, cancer-related muscle wasting. The large “POWER” trials found ostarine increased lean body mass but did not reliably improve physical function ‚Äî the functional endpoint regulators required. The programme was not approved, and development for that indication ended.

The honest limitation: those studies used low doses over limited periods under medical supervision. Ostarine has never been approved, its long-term safety is not established, and the case-report literature includes documented drug-induced liver injury from enobosarm. We publish the limitations alongside the findings because that’s what accurate research context requires. Our full research summary of ostarine’s side effects covers the documented signals in detail.

Quality and verification

Independent analysis on every batch, before it reaches you:

• >99% purity confirmed by HPLC (high-performance liquid chromatography)
• Identity and structure confirmed by mass spectrometry, with contaminant screening
• Two independent rounds of analysis per batch
• UK manufacture to pharmaceutical-grade laboratory standards
• Certificate of Analysis supplied ‚Äî see how to read a SARM certificate of analysis

Why this matters specifically for ostarine: it is among the most frequently counterfeited compounds in this category. Published analytical work has found that a substantial proportion of products sold as SARMs contain a different compound, an incorrect quantity, or no active ingredient at all. If you’re comparing your results against the clinical literature, an unverified starting material invalidates the comparison. More on our approach: the role of HPLC in SARMs testing and our UK SARMs certificate of analysis.

Research applications

Supplied as a characterised reference material for in-vitro and laboratory research, including:

• Androgen receptor binding, agonism and tissue-selectivity studies
• Musculoskeletal, sarcopenia and body-composition research models
• Comparative SARM pharmacology ‚Äî ostarine is the standard benchmark compound
• Analytical method development, assay calibration and reference standardisation
• Anti-doping detection and metabolite identification work

Storage and handling

Store in a cool, dry place away from direct light, with solution and lyophilised formats handled according to their respective stability profiles. Our 10-step guide to storing SARMs safely sets out best practice for a UK research setting, and appropriate laboratory PPE should be worn when handling any research chemical.

Frequently asked questions

What is ostarine?
A non-steroidal selective androgen receptor modulator (SARM), also known as MK-2866 or enobosarm, supplied here as a research-grade reference compound.

Why is ostarine used as a benchmark compound?
Because it has the largest published human dataset of any SARM — reaching Phase 3 trials — so results can be compared against an established body of literature.

How does ostarine compare to LGD-4033?
Ostarine progressed further clinically; LGD-4033 is more potent by weight and active at sub-milligram levels. Both act on the androgen receptor with similar categories of documented effect.

Is ostarine legal in the UK?
It is not licensed for human use and must not be marketed or sold for human consumption. It may be supplied for legitimate laboratory research. Full detail: are SARMs legal to buy in the UK for research purposes?

Is ostarine detectable in anti-doping testing?
Yes. It has been on the WADA prohibited list since 2008 and is one of the most commonly detected SARMs in anti-doping screening — see can SARMs be detected in drug tests?

What purity do you supply?
>99%, HPLC-verified, with a certificate of analysis and two independent rounds of testing per batch.

Research reading

• What is ostarine (MK-2866)? ‚Äî the complete UK research guide
• Reviewing the research on ostarine ‚Äî trial-by-trial summary
• Ostarine side effects ‚Äî full research summary
• Do SARMs increase testosterone? ‚Äî what the suppression data shows
• SARMs UK guide ‚Äî the complete research overview
• Browse the full research SARMs range

Important compliance information

This product is supplied strictly for laboratory and analytical research use only. It is not a medicine, not a dietary supplement, and not for human or veterinary consumption. Ostarine is not approved by the MHRA, FDA, or any regulator for human use, and is prohibited in sport by WADA.

Max Muscle Labs does not provide dosing guidance, usage protocols, or any information implying human use. By purchasing, you confirm you are a qualified researcher or institution and will use this material in accordance with all applicable laws and research-conduct standards.

Sources

• PubChem ‚Äî Ostarine / Enobosarm (CID 11326715)
• Dalton et al. (2011), enobosarm Phase 2 in healthy elderly
• Is ostarine safe and effective? ‚Äî efficacy and safety review (PMC8200429)
• Phase 3 POWER trials of enobosarm (PMC4853438)
• Drug-induced liver injury from enobosarm (PubMed 34368386)
• USADA ‚Äî SARMs, prohibited class