Growth-hormone secretagogues & GH-axis peptides
Ibutamoren (MK-677)
Also known as MK-677 · MK-0677 · ibutamoren mesylate
An orally active, non-peptide growth-hormone secretagogue that mimics ghrelin at the GHS-R1a receptor.
In 60 seconds
Studied in clinical trials from the 1990s (catabolism, ageing, frailty); never approved. Reported effects include oedema, increased appetite and muscle pain; a 2025 case report described hepatotoxicity, and a 2024 case linked an adulterated performance supplement to gynaecomastia.
- A randomised, placebo-controlled crossover study measured MK-677’s effect on diet-induced negative nitrogen balance in healthy volunteers.
- In dogs, repeated MK-0677 produced sustained GH and IGF-1 elevations, with cortisol also increased.
- Case report of liver injury in a healthy man in his early 30s using MK-677.
Mechanism
MK-677 is a small molecule (not a peptide) that activates the ghrelin receptor, producing sustained increases in GH and IGF-1. Its oral activity and long duration made it a reference compound in secretagogue research; it also raises appetite and, to a degree, cortisol.
Research status
Studied in clinical trials from the 1990s (catabolism, ageing, frailty); never approved. Widely sold as a "research chemical" and banned in sport.
Key studies
A randomised, placebo-controlled crossover study measured MK-677’s effect on diet-induced negative nitrogen balance in healthy volunteers.
MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism — J Clin Endocrinol Metab, 1998 · PMID 9467534
In dogs, repeated MK-0677 produced sustained GH and IGF-1 elevations, with cortisol also increased.
Repeat administration of the GH secretagogue MK-0677 increases and maintains elevated IGF-I levels in beagles — J Endocrinol, 1997 · PMID 9071975
Case report of liver injury in a healthy man in his early 30s using MK-677.
Hepatotoxicity induced by MK-677 — BMJ Case Rep, 2025 · PMID 40675653
Reviews GH secretagogues including MK-677, noting conflicting long-term GH safety data.
The Safety and Efficacy of Growth Hormone Secretagogues — Sex Med Rev, 2018 · PMID 28400207
Safety signals in the literature
Reported effects include oedema, increased appetite and muscle pain; a 2025 case report described hepatotoxicity, and a 2024 case linked an adulterated performance supplement to gynaecomastia.
Legal status (South Africa)
Not a registered medicine for human use in South Africa unless SAHPRA-registered under its own name; growth-hormone secretagogues are prohibited in sport under the WADA list. Supplied, where we stock it, strictly for laboratory research.
Related compounds we stock
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Comparisons
Questions
What is Ibutamoren (MK-677)?
An orally active, non-peptide growth-hormone secretagogue that mimics ghrelin at the GHS-R1a receptor. MK-677 is a small molecule (not a peptide) that activates the ghrelin receptor, producing sustained increases in GH and IGF-1. Its oral activity and long duration made it a reference compound in secretagogue research; it also raises appetite and, to a degree, cortisol.
What is the research status of Ibutamoren (MK-677)?
Studied in clinical trials from the 1990s (catabolism, ageing, frailty); never approved. Widely sold as a "research chemical" and banned in sport.
What safety signals are reported for Ibutamoren (MK-677)?
Reported effects include oedema, increased appetite and muscle pain; a 2025 case report described hepatotoxicity, and a 2024 case linked an adulterated performance supplement to gynaecomastia.
Does Living Water Labs stock Ibutamoren (MK-677)?
Not at present. Ibutamoren (MK-677) is profiled here for reference, with citations to the published literature. You can ask to be notified if we add it. Not a registered medicine for human use in South Africa unless SAHPRA-registered under its own name; growth-hormone secretagogues are prohibited in sport under the WADA list. Supplied, where we stock it, strictly for laboratory research.
More in GH secretagogues
Research reference only. This page summarises published literature; it is not medical advice and contains no guidance on human use. Products supplied by Living Water Labs are for laboratory research only.
