SARMs
Ostarine (MK-2866 / Enobosarm)
Also called MK-2866 · Enobosarm
Ostarine appeals to lifters who want to keep muscle while cutting or add modest size without injections. Reported experiences range from worthwhile strength and physique changes to disappointment. Its reputation as a mild SARM does not mean it avoids hormone, cholesterol or liver risks.
Dosage & duration
Published phase 2 study · older men and postmenopausal women
The “mild SARM” question
Muscle goals and the trade-offs
What people seek
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Keep muscle on a cut
Retaining strength and muscle is a reported goal.
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Modest size gains
Experiences range from worthwhile changes to disappointment.
What to weigh
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Different study population
The lean-mass trial studied older adults, not dieting lifters.
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Hormone and cholesterol changes
The “mild” reputation does not establish low risk.
Why lifters consider Ostarine
Cutting without losing strength, modest lean gains and an oral alternative to injected steroids are reported goals among people considering Ostarine. Some readers also hope to avoid hair or mood problems they associate with testosterone. Those are reasons for interest, not proof that switching to Ostarine solves them.
What people report — and what that means
Some people report better pumps and strength; others feel the gains are too small to justify changes in bloodwork. Several positive accounts include other drugs. A transformation photo or a strong workout cannot show how much came from Ostarine, training, diet or the rest of a stack.
Is it a fat burner or a muscle-retention drug?
The cutting appeal is mainly holding onto muscle, rather than expecting rapid fat loss from a pill. An 86-day study in older men and postmenopausal women found increased lean mass and improved stair-climb power. A small fat-mass difference also appeared. That is not a trial of trained lifters dieting for a show.
What the mild label leaves out
In that study, HDL cholesterol fell. Total testosterone also fell in men alongside its binding protein, while free testosterone did not significantly change. That specific result does not prove recreational use is nonsuppressive. FDA warns that unapproved SARM products can cause serious harm, including liver injury. There is no approved bodybuilding course, and the study dose shown above is not a starting recommendation.
Model details: Ostarine (MK-2866 / Enobosarm) · relative timing
Compare timing and buildup for this compound. The values are not blood concentrations or a measure of strength.
Shows a relative timing scenario; absolute blood concentrations are not calibrated.
Timing assumptions and sources
Coss 2016 study 1 parent drug;1 hmedian Tmax,22 hmean terminal.
One 1 mg input peaks at 1 relative unit after a single dose. Other amounts scale proportionally; overlapping doses add when accumulation is on. Different compounds use separate relative scales.
- Timing half-life used
- 22 hours
- Absorption half-life assumed
- 0.1353075 hours
- Reference amount for the relative scale
- 1 mg
- The faster rate is inferred to match the 1 h source-scoped peak time; absorption half-life 0.13530751987917727 h is a mathematical shape parameter, not separately measured.
- A single 1-unit input has a peak of 1 relative unit; scaling and repeated-dose addition are mathematical assumptions. This normalization is independent of the example dose.
- One-compartment AUC 1834 is 2.44×source 752.3; long terminal phase has lower weight.
- 15 mg UI default is 5×selected 3 mg study, not verified individual dose response.
- No extra 100% F; relative fallback remains explicit until a multiphasic fit is established.
- Coss et al 2016 enobosarm drug interactions
Study 1 Table 2 unaccompanied 3 mg:Cmax 56, AUC 752.3, h 22, Tmax 1; glucuronide analyzed separately.
- Coss 2016 full text mirror
Table 2 confirms geometric mean 56 vs arithmetic 57.6; do notuse metabolite 71.3 or interaction arm.
ostarine-relative-timing-2026-10 · version 1
Safety and interaction notes Read the limitations and discuss clinical questions with a professional
- Aromatizes
- No
Human studies observed hormone and lipid changes. FDA warns of serious adverse effects with unapproved SARMs; trial participation is not evidence of a safe recreational course.
Common questions
Is Ostarine a safer substitute for testosterone?
That comparison has not been established for bodybuilding use. Some people consider it to avoid injections or particular steroid side effects, but SARM selectivity does not eliminate systemic risks.
Will Ostarine preserve muscle during a cut?
That is a reported goal. Research in older adults supports an effect on lean mass, but it does not predict muscle retention during a trained lifter’s calorie deficit or guarantee that gains remain after stopping.
Sources Labels, studies and notes behind this guide
Catalog evidence: Human clinical trials. This describes the type of evidence, not a clinical review of every claim.
Summary and fact source checks: 2026-10-10, 2026-10-07. This records source checking, not medical review of the whole page.
Notes on the quick facts
- Why people seek it
- Cutting is a common reader goal, not a guarantee of fat loss.
- Human evidence
- The trial population and amounts differ from many gym reports.
- Main trade-off
- The mild-SARM label should not be read as risk-free.
- 1. Dalton et al. — enobosarm phase 2 trial
Primary full-text XML independently checked: older men/postmenopausal women, 3 mg/day for 86 days. Lean-mass/stair-climb effects and a small secondary fat-mass difference of approximately 0.6 kg versus placebo (P=.049). HDL/total-testosterone changes, without significant free-testosterone fall in that trial. Not a trained-lifter dosing study.
- 2. FDA — SARMs are unapproved drugs
Full FDA warning read 2026-10-10. Class warning includes liver injury, sexual dysfunction and infertility; it does not estimate the risk of each individual SARM.
- 3. FDA — SARM warning
Unapproved status and serious adverse-event warnings; not individual compound risk frequency.
- 4. Coss et al 2016 enobosarm drug interactions
Study 1 Table 2 unaccompanied 3 mg:Cmax 56, AUC 752.3, h 22, Tmax 1; glucuronide analyzed separately.
- 5. Coss 2016 full text mirror
Table 2 confirms geometric mean 56 vs arithmetic 57.6; do notuse metabolite 71.3 or interaction arm.
- 6. Dobs et al., enobosarm in cancer-associated muscle wasting
Randomized phase II cancer-population study; distinct from healthy gym users and not regulatory approval.
Keep reading
Related compounds and examples
Related compounds
Ligandrol (LGD-4033)
Ligandrol attracts lifters looking for fuller muscles, size and strength without injections. The question that keeps coming up is how much of that fuller look remains after stopping. Human research found a lean-mass increase, alongside hormone and cholesterol changes; individual transformation reports cannot predict the result for another person.
Andarine (S4)
Andarine is sought for a harder, more defined look and strength during a cut, rather than dramatic weight gain. Users compare it with Anavar or Ostarine, but those comparisons are anecdotal. Yellow or green vision and difficulty seeing in low light are a distinctive concern in reports, not a harmless sign that the product is working.
Testolone (RAD-140)
RAD-140 appeals to lifters chasing stronger lifts, noticeable pumps and a muscular look without injections. Experience reports also describe disrupted sleep, hair shedding and blood-pressure concerns. Testolone is not testosterone, and its human cancer research does not establish a safe bodybuilding substitute.