MK-677 (Ibutamoren) is one of the most researched growth hormone secretagogues available. Unlike SARMs, it works by mimicking ghrelin to stimulate natural GH and IGF-1 release — making it unique in the research compound space. Here's everything the clinical data shows. For research purposes only.
MK-677 (also called Ibutamoren or Nutrobal) is an orally active growth hormone secretagogue developed by Merck. It works by mimicking the action of ghrelin — the "hunger hormone" — at the ghrelin receptor (GHSR), which stimulates the pituitary gland to release more growth hormone and subsequently increases IGF-1 levels.
It was studied for conditions including growth hormone deficiency, muscle wasting, obesity and bone density loss. Multiple Phase II trials have been completed, though no regulatory approval has been granted.
⚠ Research Purposes Only: MK-677 is not approved for human consumption by the FDA or MHRA. All information on this page is for educational and research purposes only.
This is a critical distinction often misunderstood online. MK-677 does not bind to androgen receptors. It is a ghrelin receptor agonist — a growth hormone secretagogue. It therefore does not carry the androgenic risks associated with SARMs and does not suppress the HPG axis (testosterone production).
This makes its research profile quite different from compounds like RAD-140 or Ostarine.
| Study | Population | Duration | Key Finding |
|---|---|---|---|
| Svensson et al. (1998) | Healthy elderly | 2 weeks | Significant GH & IGF-1 elevation at 25mg |
| Nass et al. (2008) | Elderly adults | 12 months | Improved lean mass, fat loss, sleep quality reported |
| Patchett et al. | GHD adults | 6 months | GH normalisation, improved body composition |
| Murphy et al. (1998) | Elderly men & women | 2 years | Sustained GH/IGF-1 elevation, appetite increase noted |
| Parameter | Clinical Data | Notes |
|---|---|---|
| Doses studied in trials | 10mg, 15mg, 25mg daily | Oral — all doses oral |
| Half-life | ~24 hours | Once-daily dosing in trials |
| Trial durations | 2 weeks to 2 years | Longest trials were 24 months |
| Peak GH elevation | 25mg dose — ~60% IGF-1 increase | Sustained across trial duration |
Research bloodwork for MK-677 protocols should include IGF-1, fasting glucose, HbA1c, prolactin and lipid panel.
This is one of MK-677's most notable research advantages. Because it does not interact with androgen receptors or suppress the HPG axis, traditional post-cycle therapy (Clomid/Nolvadex) is not typically indicated in MK-677 research protocols. GH and IGF-1 levels return to baseline after discontinuation.
However, bloodwork monitoring (IGF-1, fasting glucose) is still advisable in long-duration research.
United States: MK-677 is not a scheduled controlled substance. It is legal to purchase as a research chemical. Not FDA-approved for human use or as a dietary supplement.
United Kingdom: MK-677 is not listed under the Misuse of Drugs Act 1971. Legal to buy as a research chemical. Not MHRA-licensed. On the WADA prohibited list for competitive athletes.
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⚠ Research Disclaimer: This article is for informational and educational research purposes only. MK-677 (Ibutamoren) is not approved for human consumption by the FDA or MHRA. Nothing here is medical advice. Consult a licensed medical professional. Some links are affiliate links.
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