MK-777 (Acetamoren)

What is MK-777 (Acetamoren)?

MK-777 is also identified by the chemical name Acetamoren. It is a non-peptide small molecule. It is currently under early-stage preclinical investigation as a ligand for the growth hormone secretagogue receptor, GHS-R1a (the ghrelin receptor). In laboratory research, it is studied for in vitro receptor binding investigation and preclinical ghrelin-pathway research.

In laboratory research models, MK-777 is studied for its interaction with key neuroendocrine pathways, including:

• Ghrelin receptor (GHS-R1a) binding and selectivity
• Growth hormone (GH) and IGF-1 axis signaling
• Hypothalamic and pituitary receptor activation in preclinical research models

Note: As of 2026, MK-777 has not been the subject of a peer-reviewed clinical or preclinical publication. 

MK-777 is not a SARM. Despite category placement in some vendor catalogs, MK-777 is a ghrelin receptor agonist. It is certainly not an androgen receptor modulator. It is not approved by the FDA for any therapeutic use. It is not a dietary supplement and is supplied exclusively as a research chemical by BehemothLabz.

ATTENTION: This product is strictly for LABORATORY AND RESEARCH PURPOSES ONLY. Not for human or veterinary use.

Mechanism of Action of MK-777 (Acetamoren)

Ghrelin Receptor (GHS-R1a) Binding Research:

MK-777 is under investigation in in vitro receptor binding assays as a non-peptide ligand at the growth hormone secretagogue receptor (GHS-R1a). Preclinical receptor-binding assay development and comparative pharmacology against the parent compound class (ibutamoren/MK-677, spiropiperidine GHS-R1a agonists) are the primary research contexts.

Comparative Non-Peptide GHS-R1a Pharmacology:

MK-777 is used in laboratory research as a reference compound within the non-peptide spiropiperidine GHS-R1a agonist family. This enables a structure-activity relationship investigation and binding-kinetics research in cell-free and cell-culture assay systems.

Chemical Properties of MK-777 (Acetamoren)

• Molecular Formula: C₂₉H₃₈N₄O₆S
• Molecular Weight: 570.7 g/mol
• CAS Number: 950841-87-9
• Synonyms: Acetamoren, MK777, MK 777
• IUPAC Name: Propanamide, 2-(acetylamino)-N-[(1R)-2-[1,2-dihydro-1-(methylsulfonyl)spiro[3H-indole-3,4′-piperidin]-1′-yl]-2-oxo-1-[(phenylmethoxy)methyl]ethyl]-2-methyl-
• Physical Form: White to off-white crystalline powder
• Solubility: Soluble in DMSO; limited aqueous solubility
• Storage: Store at −20°C, protected from light and moisture
• Classification: Research Use Only 

The values above reflect the ChemicalBook reference entry for CAS 950841-87-9.

Research Applications of MK-777 (Acetamoren)

1. GHS-R1a Receptor Binding Assay Research

MK-777 is investigated in in vitro ghrelin receptor (GHS-R1a) binding assay characterization. In cell-free receptor preparation systems, it serves as a reference non-peptide ligand for binding kinetics and receptor occupancy studies.

2. Structure-Activity Relationship (SAR) Studies

As a member of the non-peptide spiropiperidine GHS-R1a agonist class, MK-777 is used in comparative SAR investigation alongside parent class compounds, including ibutamoren (MK-677). 

3. Preclinical Ghrelin Pathway Pharmacology

MK-777 is investigated in ghrelin receptor-transfected cell line systems for preclinical pharmacology research. It serves as a reference compound for competitive binding displacement assays in experimental settings.

4. Analytical Chemistry Method Development

MK-777 is used in analytical chemistry method development for the spiropiperidine chemical series. This includes HPLC retention time characterization and mass spectrometry confirmation against CAS 950841-87-9 reference data.

5. Comparative GHS-R1a Agonist Research

In laboratory settings, MK-777 is compared against other non-peptide GHS-R1a agonists to investigate receptor selectivity profiles and binding kinetics. Evidence remains mixed, and data are limited to in vitro experimental systems.

Risk & Handling

MK-777 is a CNS-active ghrelin receptor agonist under early-stage preclinical investigation. Researchers must observe the following precautions at all times.

Risk Tier: HIGH 

This rating reflects the complete absence of toxicological data for MK-777, unknown receptor affinity and selectivity profile, potential bioactive effects on neuroendocrine pathways if GHS-R1a activity is confirmed, and elevated regulatory exposure associated with growth hormone secretagogue pathway compounds under the Anti-Drug Abuse Act of 1988. Researchers must observe the following precautions at all times. 

Handling Precautions: MK-777 should be handled exclusively in a controlled laboratory environment by trained personnel. Avoid skin and eye contact. Use appropriate PPE, including gloves, a lab coat, and eye protection, when handling the compound. Work in a well-ventilated area or under a fume hood where possible.

Storage: Store lyophilized or powdered MK-777 at −20°C. Store in a dry, dark environment. Protect from light, heat, and moisture at all times. Avoid repeated freeze-thaw cycles. 

Toxicity & Dependency Considerations: As a ghrelin receptor agonist, MK-777 mechanistically interacts with pathways involved in growth hormone regulation. The long-term toxicity profile of MK-777 in any biological system is entirely unknown. Data remains limited, and findings should not be extrapolated to human biology.

Why Choose BehemothLabz to Buy MK-777 (Acetamoren)?

Behemoth Labz supplies research-grade MK-777 (Acetamoren) for laboratory research purposes. It goes through quality control and third-party testing for consistency, purity, and research-grade standards. Given the variation seen across supplier specifications for this compound, the site provides batch-specific identity confirmation against CAS 950841-87-9, which is a key parameter for reproducible experimental design.

BehemothLabz Disclaimer

ATTENTION: All BehemothLabz products are strictly for LABORATORY AND RESEARCH PURPOSES ONLY. They are not to be used for any human or veterinary purposes.

Please make sure you go through the Terms and Conditions and familiarize yourself with them, as it is important. Kindly research the scientific uses of this product before making any purchases. Make note that the packaging and labels of the product may differ from those shown on the website.

Buying the product means you agree to our Terms and Conditions. You can contact our customer service team at support@behemothlabz.com if you are not fully satisfied with the product.

Enhanced Disclaimer — GH Secretagogue Class: This product is a research chemical for laboratory use only. NOT approved by the FDA for human use and prohibited for human consumption or injection. Growth hormone is controlled under the Anti-Drug Abuse Act of 1988 and may only be distributed with a valid prescription. Compounds that stimulate endogenous growth hormone release, such as ghrelin receptor agonists, carry significantly elevated regulatory exposure and are supplied strictly for in vitro bioassay and preclinical model research only. Unauthorized human use or distribution may violate federal law. Purchaser assumes all liability for federal and state law compliance.

MK-777 (Acetamoren) Research FAQs

What is MK-777 (Acetamoren)? 

MK-777, also known as Acetamoren, is a non-peptide small molecule investigated in early-stage preclinical research as a GHS-R1a ghrelin receptor ligand. It is structurally related to ibutamoren (MK-677) but is a chemically distinct compound. It is not approved for human or veterinary use. BehemothLabz supplies it strictly for laboratory research.

How does MK-777 interact with GHS-R1a in experimental settings? 

In in vitro receptor binding assays, MK-777 is investigated as a non-peptide ligand at the GHS-R1a receptor. GHS-R1a is a G protein-coupled receptor expressed in the pituitary and hypothalamus. Its activation in preclinical models has been associated with intracellular signaling cascades involved in growth hormone regulation. These observations are from in vitro and preclinical model systems only.

Are there peer-reviewed studies on MK-777? 

As of 2026, no peer-reviewed clinical or preclinical publications specific to MK-777 (Acetamoren) are available. Available research context is drawn from the parent compound, ibutamoren (MK-677) only.

Is MK-777 (Acetamoren) safe for human use? 

No. The FDA does not approve MK-777 for human or veterinary use. No regulatory body has cleared this research-grade formulation for any health application. The long-term toxicity profile in any biological system is entirely unknown. BehemothLabz supplies it for laboratory research only. 

How should MK-777 (Acetamoren) be stored? 

Store at −20°C in a dry, dark environment, protected from light, heat, and moisture. Avoid repeated freeze-thaw cycles. For storage questions, contact support@behemothlabz.com

References:

Research Transparency Note: As of 2026, no peer-reviewed studies specific to MK-777 (Acetamoren) exist. The following references relate to the parent compound class (MK-677/ ibutamoren) and GHS-R1a pharmacology that provides investigational context for MK-777 research. 

 

However, the following research/studies relate to the mechanism of the subject product:

 

1. Howard, A. D., Feighner, S. D., Cully, D. F., et al. (1996). A receptor in the pituitary and hypothalamus that functions in growth hormone release. Science, 273(5277), 974–977. https://pubmed.ncbi.nlm.nih.gov/8688086/
2. Hickey, G. J., Jacks, T. M., Schleim, K. D., et al. (1997). Repeat administration of the GH secretagogue MK-0677 increases and maintains elevated IGF-I levels in beagles. Endocrinology, 138(10), 4556–4561. https://pubmed.ncbi.nlm.nih.gov/9071975/
3. Smith, R. G. (2005). Development of growth hormone secretagogues. Endocrine Reviews, 26(3), 346–360. https://pubmed.ncbi.nlm.nih.gov/15814847/