TL;DR: MK-777 (also written MK777 and MK 777, and sold under the name acetamoren) is a small-molecule research compound. Registry data show it is an N-acetyl derivative of ibutamoren (MK-677), and no peer-reviewed study of the compound under the name MK-777 or acetamoren was found. Transparent Peptides lists MK-777 (Acetamoren) Capsules for laboratory research use only.
What is MK-777 (acetamoren)?
MK-777 is a supplier name. The registry number CAS 950841-87-9 is linked to the names acetamoren and MK777. PubChem lists that registry number under compound CID 57595228 with the molecular formula C29H38N4O6S and a molecular weight of 570.7. Ibutamoren (MK-677), CID 178024, has the formula C27H36N4O5S and a molecular weight of 528.7. The difference between the two formulas is C2H2O, which corresponds to one acetyl group.
Suppliers market MK-777 as a ghrelin-receptor (GHS-R1a) agonist. That description has not been confirmed in published studies: a PubMed search for “acetamoren” returned no records when checked on November 10, 2026, so the compound’s pharmacology rests on supplier descriptions rather than published data.
MK-777 vs MK-677 (ibutamoren)
| Property | MK-777 (acetamoren) | MK-677 (ibutamoren) |
|---|---|---|
| Registry formula | C29H38N4O6S (570.7) | C27H36N4O5S (528.7) |
| Structural relationship | N-acetyl derivative of ibutamoren, per registry formulas | Parent compound |
| Published peer-reviewed studies | None found under the names MK-777 or acetamoren | Published studies exist, for example 1996 and 1998 in the Journal of Clinical Endocrinology and Metabolism |
| Transparent Peptides listing | MK-777 (Acetamoren) Capsules: bottle of 90 capsules, 10mg each | MK-677 (Ibutamoren) Capsules: bottle of 90 capsules, 10mg each; MK-677 Liquid: liquid research solution, 30mg per ml |
Researchers comparing the two compounds should regard any claim that MK-777 differs from MK-677 in potency or selectivity as unverified until independent data are published. For background on the reference compound, see our MK-677 research overview.
MK-777 capsule specifications
- Format: bottle of 90 capsules, 10mg of MK-777 each
- Form: encapsulated research material
- Storage: controlled room temperature (15–25°C), cool and dry, away from direct light; keep the container tightly closed
- Documentation: certificate of analysis (COA) available on request for research records
Order from the MK-777 (Acetamoren) Capsules product page. Sold only to qualified researchers; shipping to the United States and Canada.
FAQ
What is MK-777?
MK-777 is a supplier name for a small-molecule research compound also called acetamoren. Registry data list it as an N-acetyl derivative of ibutamoren (MK-677).
Is MK-777 the same as MK-677?
No. The registry formulas differ by one acetyl group (C29H38N4O6S for MK-777 and C27H36N4O5S for MK-677), so they are related but distinct compounds.
Are there published studies on MK-777?
No peer-reviewed study under the names MK-777 or acetamoren was found in a PubMed search on November 10, 2026.
Is a COA available for MK-777?
Yes. A certificate of analysis (COA) is available on request for research records. Contact our support team with the product name.
How should MK-777 capsules be stored?
Store the sealed bottle at controlled room temperature (15–25°C) in a cool, dry place away from direct light. Follow your institution’s SOPs.
Is MK-777 for human use?
No. MK-777 is sold strictly for laboratory research use only. It is not a drug, food or dietary supplement, and is not for human or veterinary consumption.
All products referenced are sold strictly for laboratory research use only and are not for human or veterinary consumption.
