Not a peptide but a spiropiperidine small molecule, agonist at the same ghrelin receptor the injectable secretagogues target, with a half-life measured in hours rather than minutes.
About MK-677
MK-677, also known as ibutamoren, is grouped with the growth hormone secretagogues because of what it does rather than what it is made of. It is a small molecule, and it is an agonist at GHSR-1a — the same receptor targeted by Ipamorelin, GHRP-2 and Hexarelin.
Two properties separate it from them. It is orally bioavailable, where a pentapeptide is not: a small molecule survives the gut. And its half-life runs to several hours, which produces a sustained elevation of growth hormone and IGF-1 rather than the discrete pulse the peptide secretagogues give.
What the research covers
Growth hormone is secreted in pulses, and much of its downstream signalling appears to depend on that pattern rather than on total exposure. A compound that flattens the pattern into a sustained elevation is therefore testing a different hypothesis from one that amplifies individual pulses, even though both are described as raising growth hormone.
That makes this the appropriate tool for work on chronic elevation and on IGF-1 as a downstream marker, and the wrong tool for work on pulsatility. The observations that accompany sustained GHSR-1a agonism — appetite signalling, fluid balance, insulin sensitivity — are part of the profile rather than incidental, and a study design needs to account for them. The MK-677 guide covers the literature, and Ipamorelin versus GHRP-2 covers the injectable agonists it is weighed against.
MK-677 specification
- Strength: 5mg
- Presentation: vial
- Purity: ≥99% by HPLC, identity confirmed by mass spectrometry
- Released against: the Certificate of Analysis for its own batch
- Reference: MK75
Handling MK-677
Because this is a small molecule rather than a peptide, the analytical picture differs from the rest of the catalogue: purity is established by HPLC against a reference standard, and the impurities that matter are synthesis-related rather than the truncation and deletion sequences relevant to peptides.
Storage is correspondingly less demanding — a spiropiperidine of this class is considerably more robust than a short peptide, and it does not share their adsorption behaviour at low concentration. Keep it dry and sealed; the usual freeze-thaw cautions that apply to reconstituted peptides are not the limiting factor here.
Further reading: growth hormone research peptides in the Amino Club research library.
Certificates, delivery and terms
This batch ships with the Certificate of Analysis carrying the batch number printed on its label; how that is tested and released is set out on the lab testing page. Delivery, customs and returns are covered on the shipping page, common questions on the FAQ, and quantity pricing through bulk and wholesale. Supplied for in-vitro laboratory research only: not a medicine, not a supplement, not for human or veterinary use, and no dosing or administration guidance is provided — see the research use policy.
