MK-677 (Ibutamoren)
Also referred to as: Ibutamoren, MK-0677, L-163191
An orally active compound (not a peptide) that nudges the body to release growth hormone through the ghrelin pathway.
In plain terms: MK-677 prompts the body to release its own growth hormone, taken by mouth rather than injected. It is not actually a peptide — it is a small molecule that mimics one — but it comes up so often alongside growth-hormone peptides that it is worth including. It is not an approved drug.
- Name
- MK-677 (Ibutamoren)
- Aliases
- Ibutamoren, MK-0677, L-163191
- Classification
- Growth-hormone secretagogue (oral, non-peptide)
- Areas studied
- Growth hormone & IGF-1, Ghrelin pathway, Oral compound
What it is
MK-677 (also called Ibutamoren) is a lab-made compound that acts like the hormone ghrelin to prompt growth-hormone release. Unlike the injectable peptides in this group, it works when taken by mouth.
It is technically not a peptide — it is a small molecule that imitates one — but it is included here because it is so commonly compared with growth-hormone peptides. Its research is mostly early-stage with some human studies.
Mechanism
MK-677 plugs into the ghrelin (GHS) docking point, the same one the peptide Ipamorelin uses, prompting the pituitary gland to release growth hormone. Because of its chemistry, it survives being swallowed, which the peptides generally do not.
The growth-hormone-to-IGF-1 chain is the system researchers track here.
Areas studied & investigated
The categories below summarize where MK-677 (Ibutamoren) appears in the research literature. They describe what the compound is studied for and investigated in — not approved uses, and not guidance for any kind of use.
Growth hormone & IGF-1
Studied for raising growth-hormone and IGF-1 levels.
Ghrelin pathway
Works through the same ghrelin signal as some growth-hormone peptides.
Oral activity
Notable for working by mouth, unlike injectable peptides.
Body composition (studied)
Looked at in human studies for effects on lean mass and metabolism.
Research history
MK-677 was developed in pharmaceutical research into orally active growth-hormone secretagogues in the 1990s and has been studied in several human trials, including in older adults.
State of the literature
MK-677 has some human trial data alongside earlier development research. It is not an approved drug.
What to keep in mind
MK-677 is not a peptide, and "raises growth hormone" is not automatically a good thing — sustained increases carry their own questions about blood sugar and fluid retention that show up in the research. The fact that it is taken orally makes it convenient to misuse. Read the human studies, and do not assume "boosts a natural hormone" means safe.
Research tools
Evaluating a MK-677 (Ibutamoren) batch for laboratory research? These free, research-use-only calculators help you work the numbers and read the paperwork: the reconstitution calculator solves vial concentration and draw volume, and the COA reader walks a certificate line by line. For how much and how often MK-677 (Ibutamoren) is commonly used, see the dosing guides.
Batch-tested with published COAs
See what a published COA looks like
Midwest Compounds does not currently list MK-677 (Ibutamoren). Every compound it does sell is tested by an independent lab, with a batch-linked certificate of analysis you can check before you buy.
Citations
The summary above is drawn from published, peer-reviewed sources. Links open the abstract on PubMed, or the free full text on PubMed Central (PMC) where marked.
- Nass R, et al. Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. Annals of Internal Medicine, 2008. Abstract
- Murphy MG, et al. MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism. Journal of Clinical Endocrinology & Metabolism, 1998. Abstract