# Ostarine (MK-2866 / Enobosarm)

*Also known as: MK-2866, Enobosarm*

Non-steroidal SARM; mild, used in cutting/recomp. Simple model (estimated).

## Overview

Ostarine (MK-2866, enobosarm) is a non-steroidal selective androgen receptor modulator developed for muscle-wasting and cachexia indications. It binds the androgen receptor with tissue-selective activity, aiming for anabolic effects in muscle and bone with less androgenic action in prostate or skin. The compound carries an estimated 24-hour half-life, supporting once-daily oral dosing, though human pharmacokinetic data are limited and the profile is modeled by comparison to related SARMs. Clinical trials at 1-3 mg produced dose-dependent lean mass gains, but higher off-label doses raise testosterone suppression, lipid shifts, and liver enzyme elevation. Ostarine is an investigational agent with no approved human use, is banned by WADA, and is frequently sold mislabeled or contaminated, so harm-reduction priorities are independent third-party testing, baseline and on-cycle bloodwork (LH, FSH, total T, lipids, ALT/AST), and a planned PCT if suppression appears.

## Pharmacokinetics

- **Model tier:** simple
- **Half-life:** 1.0 days (24 hours)
- **Bioavailability:** 100%

## Dosing

- **Default dose:** 15 mg
- **Typical range:** 10–25 mg
- **Units:** ng/mL

## Harm reduction

- **Aromatizes:** No
- **Hepatotoxicity:** mild
- **Injection frequency:** Oral, daily

## Detection time (anti-doping)

- **Window:** 6–9 days post-last-dose
- **Target metabolite:** Ostarine glucuronide + M4b metabolite
- **Assay:** LC-MS/MS
- **Notes:** Parent + phase I metabolite M4b detectable up to ~9 days after microdose.

## Source

- **Label:** Ostarine PK (estimated)
- **URL:** https://pubmed.ncbi.nlm.nih.gov/24074268/
- **Notes:** Estimated by comparison to LGD-4033.

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**Canonical URL:** https://anabolicdex.com/compounds/ostarine
**Plot:** https://anabolicdex.com/plot?compound=ostarine