Peptide

MK-677 (Ibutamoren)

Oral growth hormone secretagogue that mimics ghrelin; studied for sarcopenia, sleep, and body composition. Not FDA-approved; banned by WADA.

Regulatory status

Not approved

FDA (U.S.): Not approved. It has been in FDA category 2 (significant safety risks) for compounding since 2022-2023, because of a possible congestive heart failure signal in a hip fracture recovery trial that was stopped early.

EMA (EU): Not approved.

How to take it

Investigated regimen: 25 mg/day orally. Only in clinical trials or supervised experimental use.

Safety

Increases appetite (ghrelin-mimetic effect), fluid retention, edema, paresthesias. Raises glucose: caution in prediabetes/diabetes. May worsen heart failure.

Effect by goal · level of evidence

Muscle mass (older adults)

improves Moderate RCT (AA)

+1.1 kg lean mass

25 mg/day for 12 months: +1.1 kg of lean mass in older adults, without significant strength gains.

View the study (RCT) →

Sleep (REM and deep)

improves Moderate RCT (AA)

↑ Deep/REM sleep

Increases deep and REM sleep by up to 50% in some trials.

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Sarcopenia and frailty

improves (modest) Low-moderate RCT (AA)

Improves markers

Improves markers of sarcopenia in some trials; side effects (edema, blood glucose) limit chronic use.

View the study (RCT) →

Information, not medical advice. Scientific evidence reflects the quality of the studies.