- ≥98% by HPLC
- Lot-matched certificate of analysis
- Ships next business day, tracked
Ibutamoren (MK-677) Capsules
Orally active non-peptide ghrelin receptor agonist in 30-capsule bottles
- FormOral capsules in a sealed bottle with desiccant
- Mol. weight528.66 g/mol
- Research areasGH and IGF-1 axis, sleep architecture, body composition, bone mineral density, appetite regulation
Overview
Ibutamoren, developed as MK-677 and also designated L-163,191, is not a peptide at all. It is a spiropiperidine small molecule engineered at Merck to reproduce the action of the growth hormone-releasing peptides at the growth hormone secretagogue receptor while surviving the gut. That distinction matters: every other compound in this department is a peptide that would be degraded by digestion, whereas MK-677 was designed from the outset for oral bioavailability, and it is the reason this product ships as capsules rather than a lyophilized vial.
Ibutamoren is a spiro-fused piperidine of 528.66 g/mol, formula C27H36N4O5S, arrived at by medicinal-chemistry optimisation of earlier peptidomimetic secretagogues rather than by trimming a peptide sequence. Published pharmacokinetic work reports a half-life near 24 hours, and that is the property behind most of its use: it provides a sustained stimulus at the growth hormone secretagogue receptor where the peptide GHRPs listed alongside it produce discrete short pulses, so the two support quite different study designs. The research literature covers the growth hormone and IGF-1 axis, sleep architecture, body composition, bone mineral density and appetite regulation. Bottles hold thirty capsules at 12.5 mg or 25 mg, sealed at room temperature with the desiccant retained.
Specifications
Identity
- CAS number
- 159752-10-0
- Molecular formula
- C27H36N4O5S
- Molecular weight
- 528.66 g/mol
Supply & purity
- Form
- Oral capsules in a sealed bottle with desiccant
- Purity
- ≥98% by HPLC; lot-matched COA available
- Available sizes
- 12.5 mg × 30 capsules, 25 mg × 30 capsules
Additional detail
- Compound class
- Non-peptide spiropiperidine growth hormone secretagogue
- Molecular target
- Growth hormone secretagogue receptor 1a (ghrelin receptor)
- Also known as
- MK-677, MK-0677, L-163,191, ibutamoren mesylate (salt form)
- Reported half-life
- Approximately 24 hours in published pharmacokinetic studies
- Research areas
- GH and IGF-1 axis, sleep architecture, body composition, bone mineral density, appetite regulation
- Storage
- Room temperature in the sealed bottle, protected from light, heat and humidity
- Reconstitution
- None required — supplied in finished capsule form
Units and conversions
The arithmetic on an oral format is unit arithmetic rather than dilution arithmetic. Use the milligram to microgram converter to line a per-unit figure up against a method written in different units.
Certificate of analysis
Every lot of Ibutamoren (MK-677) Capsules is released against a certificate of analysis: the batch-specific laboratory data for that lot, not a generic document for the compound. The lot number on the certificate matches the lot number printed on the label you receive — the vial label itself, where the product is vialled — so the record and the material it describes can always be reconciled.
Purity: ≥98% by HPLC — the specification for this listing. The figure for the lot you receive is the one reported on that lot’s certificate.
No lot certificate is on display on this page at the moment. That is a publishing state and not a testing one: lots are released and documented as described above whether or not the document is posted here, and we will send what exists for the lot in stock, or for a lot already on your bench, by its number.
Certificates are available on request before you order as well as after, with no account and no charge. Request the certificate for this listing, read the testing and documentation policy in full, or see how to read a peptide COA.
Questions about Ibutamoren (MK-677) Capsules
Is MK-677 actually a peptide?
No. Ibutamoren is a non-peptide spiropiperidine small molecule designed to mimic peptide secretagogues at the ghrelin receptor. Because it lacks a peptide backbone it survives digestion, which is why it is supplied as capsules rather than as a lyophilized powder for reconstitution.
Is the product third-party tested and is a COA available?
Yes. Each lot is analysed by an independent laboratory for purity by HPLC and identity by mass spectrometry, and capsule content is verified against label strength. The certificate of analysis is matched to the lot number on your bottle and available on request.
How should MK-677 capsules be stored?
Keep the bottle sealed at room temperature with the desiccant in place, protected from light, heat and humidity. Unlike lyophilized peptides, no refrigeration or freezing is needed. Avoid bathroom-style humid storage, which softens capsule shells and can cause them to adhere.
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