MK-677
Also known as: Ibutamoren · Ibutamoren Mesylate · MK-0677
MK-677 is an orally-active ghrelin receptor agonist developed by Merck in the 1990s. Stimulates GH and IGF-1 release through the same axis ipamorelin uses, but in pill form. Trial data is robust, including a long-term Alzheimer's-prevention study. Failed to commercialise; sold as research chemical, popular for sleep and appetite effects.
Last reviewed · Panya.health editorial
Panya scores vendors against an 11-signal rubric. Vendors at or above 70 out of 100 are routable; below 70 are documented but get no Panya affiliate link. For prescription peptides like Mounjaro and Wegovy, Panya routes today through licensed clinicians. For research peptides like MK-677, vendor scorecards land in a follow-up sprint after legal review and payment processor selection. Until then, the page surfaces commonly-mentioned vendor names so adults can do their own diligence. We do not yet earn commission on any MK-677 vendor.
Not medical advice. MK-677 is not approved for human medical use in most jurisdictions. The data below is what users do; it is not what regulators have validated. You decide your risk profile.
What it does, and how
Ibutamoren binds the GHSR-1a (ghrelin receptor) on pituitary somatotrophs, mimicking endogenous ghrelin and triggering pulsatile GH release. Unlike injectable ghrelin agonists, it's orally bioavailable with a half-life of around 4 to 6 hours, which produces a sustained 24-hour GH AUC increase rather than a single pulse. Long-term human studies (notably Murphy et al. 1998 in elderly subjects, and a 2-year Alzheimer's prevention trial) showed sustained increases in IGF-1 and lean body mass. Merck never brought it to market, partly because sustained IGF-1 elevation has theoretical concerns the company didn't want to litigate against an aging-related indication.
Typical practice
Community practice runs 10 to 25 mg per day orally, taken at night before sleep. The nighttime dose aligns with the natural GH peak during deep sleep. Cycles 8 to 16 weeks; some users run continuously. Onset of subjective effects (improved sleep depth, increased appetite, vivid dreams) is fast, often within 2 to 4 days. The original trial doses ran 10 to 25 mg daily for up to 24 months without a documented worsening safety profile, though numerous users report water retention and edge insulin-resistance signals at the higher end of that range.
The dosing above is community practice, not a regulator-validated protocol. Trial-validated dosing for MK-677 in humans does not exist for most use cases listed.
Risks and contraindications
Most-reported side effects: water retention, mild edema, increased hunger (sometimes welcome, sometimes not), occasional carpal tunnel tingling. The bigger concerns are insulin-resistance signals: the long Alzheimer's trial (Sevigny et al. 2008) reported elevated fasting glucose and HbA1c in some participants. Sustained IGF-1 elevation has theoretical cancer-promotion concerns, though no signal emerged in 24-month follow-up. Heart failure: a Merck cardiovascular outcome trial in elderly hip-fracture patients was halted in 2003 after numerically more heart failure events on MK-677. Users with cardiovascular disease, diabetes, or active cancer should not use this. Get fasting glucose and HbA1c at baseline and every 8 to 12 weeks if running long cycles.
Where this stands legally
Not FDA-approved. Merck stopped clinical development in early 2000s. Sold widely as research chemical online; legal grey zone for human use.
Not licensed by MHRA. Research-chemical category.
Not on EMA's approved list.
TGA Schedule 4 (prescription-only) since 2017. WADA-prohibited in competitive sport.
Not formally scheduled. Available through Bangkok performance-focused vendors.
Where users say they source it
Names below are sourced from community discussion. None are currently scored against the Panya 11-signal rubric. Panya does not earn commission on any of these. You can search them yourself; treat the list as a starting point for your own diligence, not an endorsement.
- Pure RawzPending Panya 11-signal audit
- Limitless LifePending Panya 11-signal audit
- Amino AsylumPending Panya 11-signal audit
- Sports Technology Labs (US, capsule format)Pending Panya 11-signal audit
Full vendor scorecards for MK-677 land in a follow-up sprint after lawyer review and payment processor selection. We will not route users to any vendor that scores below 70 on the rubric.
Papers worth reading directly
- Murphy et al. — MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism. J Clin Endocrinol Metab, 1998 →
- Nass et al. — Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults. Ann Intern Med, 2008 →
- Sevigny et al. — Growth hormone secretagogue MK-677: no clinical effect on AD progression in a randomized trial. Neurology, 2008 →
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Adjacent reading
Track MK-677 in your peptide journal.
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