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MK-677

Ibutamoren · Ibutamoren Mesylate · L-163191 · MK677

GH SecretagoguePhase II
From$0.07/mgCompare prices
MW
624.8g/mol
Formula
C28H40N4O8S2

MK-677, also known as ibutamoren, is an orally active growth hormone secretagogue that mimics the action of growth hormone-releasing peptides. Researchers primarily study MK-677 for its potential effects on body composition, muscle mass, and bone health, particularly in catabolic states and aging populations. Key findings indicate that MK-677 can reverse diet-induced protein catabolism and significantly increase serum levels of insulin-like growth factor I (IGF-I), which is associated with enhanced bone turnover and muscle mass. Additionally, studies suggest that co-administration with other compounds may influence body composition and hormonal profiles. Current research continues to explore the long-term effects and safety profile of MK-677 in various populations, including the elderly and individuals with specific health conditions.

Chemical Profile

Chemical Profile

Chemical structure
Chemical Structure
FormulaC28H40N4O8S2
Molecular Weight624.8 g/mol
CAS Number159752-10-0
PubChem CID6450830
ChEMBL IDCHEMBL4520674

Half-Life

INIntranasal

Not applicable

POOral

~4 to 6 hours

MK-677 is primarily administered orally due to its high bioavailability and prolonged effect on GH levels.

Mechanism

Mechanism of Action

MK-677 acts as a selective agonist of the growth hormone secretagogue receptor (GHSR), stimulating the release of growth hormone (GH) from the pituitary gland through the activation of the GHSR signaling pathway. This leads to increased levels of insulin-like growth factor I (IGF-I), which mediates various anabolic processes such as protein synthesis, bone turnover, and nitrogen balance. Although the precise mechanisms underlying its effects on muscle and bone metabolism are not fully understood, MK-677 is known to enhance markers of bone formation and resorption, indicating its role in bone remodeling processes.

Research

32 Research Publications

1,840

Total Citations

20

Human/RCT

3.4

Avg. Influence

2025

Latest

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#01

Stimulation of the growth hormone (GH)-insulin-like growth factor I axis by daily oral administration of a GH secretogogue (MK-677) in healthy elderly subjects.

HumanInfluence13.0
277
The study demonstrated that MK-677 administration in healthy elderly subjects significantly increased pulsatile GH release and serum IGF-I concentrations, restoring them to levels typical of young adults.
25 mgoral(human)7 days4 mg/kgoral(rat)6 weeks10 mgoral(human)2 weeks25 mgoral(human)2 weeks5 mgoral(human)2 weeks25 mgoral(human)8 weeks50 mgoral(human)4 weeks10 mgoral(human)4 days25 mgoral(human)7 days25 mgoral(human)12 months25 mgoral(human)8 weeks25 mgoral(human)2 weeks25 mgoral(human)1 year
PubMed
#02

Oxindole derivatives as orally active potent growth hormone secretagogues.

AnimalInfluence1.0
232
Researchers observed that the oxindole derivative SM-130686 exhibited potent growth hormone releasing activity and a favorable pharmacokinetic profile in rats.
25 mgoral(human)7 days4 mg/kgoral(rat)6 weeks10 mgoral(human)2 weeks25 mgoral(human)2 weeks5 mgoral(human)2 weeks25 mgoral(human)8 weeks50 mgoral(human)4 weeks10 mgoral(human)4 days25 mgoral(human)7 days25 mgoral(human)12 months25 mgoral(human)8 weeks25 mgoral(human)2 weeks25 mgoral(human)1 year
PubMed
#03

Two-month treatment of obese subjects with the oral growth hormone (GH) secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure.

HumanInfluence4.0
172
Researchers observed that MK-677 treatment in obese males resulted in increased GH secretion and fat-free mass, but did not significantly reduce total or visceral fat.
25 mgoral(human)7 days4 mg/kgoral(rat)6 weeks10 mgoral(human)2 weeks25 mgoral(human)2 weeks5 mgoral(human)2 weeks25 mgoral(human)8 weeks50 mgoral(human)4 weeks10 mgoral(human)4 days25 mgoral(human)7 days25 mgoral(human)12 months25 mgoral(human)8 weeks25 mgoral(human)2 weeks25 mgoral(human)1 year
PubMed
#04

Nonpeptide and peptide growth hormone secretagogues act both as ghrelin receptor agonist and as positive or negative allosteric modulators of ghrelin signaling.

In VitroInfluence12.0
126
The study demonstrated that MK-677 acts as a ghrelin receptor agonist, influencing various signaling pathways and potentially modulating ghrelin function.
25 mgoral(human)7 days4 mg/kgoral(rat)6 weeks10 mgoral(human)2 weeks25 mgoral(human)2 weeks5 mgoral(human)2 weeks25 mgoral(human)8 weeks50 mgoral(human)4 weeks10 mgoral(human)4 days25 mgoral(human)7 days25 mgoral(human)12 months25 mgoral(human)8 weeks25 mgoral(human)2 weeks25 mgoral(human)1 year
PubMed
#05

MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism.

Murphy M G, et al. · The Journal of clinical endocrinology and metabolism · 1998

HumanInfluence2.0
94
The study demonstrated that MK-677 significantly improved nitrogen balance in healthy human volunteers during caloric restriction, suggesting its potential to reverse diet-induced catabolism.

Key findings

  1. 01MK-677 improved nitrogen balance during caloric restriction, reversing diet-induced protein loss.
  2. 02Participants taking MK-677 had higher levels of insulin-like growth factor-I (IGF-I) compared to those on placebo.
  3. 03The study indicated that MK-677 was well tolerated with no significant adverse effects reported.
25 mgoral(human)7 days4 mg/kgoral(rat)6 weeks10 mgoral(human)2 weeks25 mgoral(human)2 weeks5 mgoral(human)2 weeks25 mgoral(human)8 weeks50 mgoral(human)4 weeks10 mgoral(human)4 days25 mgoral(human)7 days25 mgoral(human)12 months25 mgoral(human)8 weeks25 mgoral(human)2 weeks25 mgoral(human)1 year
PubMed
#06

Prolonged oral treatment with MK-677, a novel growth hormone secretagogue, improves sleep quality in man.

Human
92
The study demonstrated that prolonged oral treatment with MK-677 significantly improved sleep quality in both young and older adults, increasing REM sleep and reducing deviations from normal sleep.
25 mgoral(human)7 days4 mg/kgoral(rat)6 weeks10 mgoral(human)2 weeks25 mgoral(human)2 weeks5 mgoral(human)2 weeks25 mgoral(human)8 weeks50 mgoral(human)4 weeks10 mgoral(human)4 days25 mgoral(human)7 days25 mgoral(human)12 months25 mgoral(human)8 weeks25 mgoral(human)2 weeks25 mgoral(human)1 year
PubMed
#07

Effect of alendronate and MK-677 (a growth hormone secretagogue), individually and in combination, on markers of bone turnover and bone mineral density in postmenopausal osteoporotic women.

HumanInfluence4.0
90
The study demonstrated that MK-677 combined with alendronate increased bone formation markers and improved bone mineral density at the femoral neck in postmenopausal osteoporotic women.
25 mgoral(human)7 days4 mg/kgoral(rat)6 weeks10 mgoral(human)2 weeks25 mgoral(human)2 weeks5 mgoral(human)2 weeks25 mgoral(human)8 weeks50 mgoral(human)4 weeks10 mgoral(human)4 days25 mgoral(human)7 days25 mgoral(human)12 months25 mgoral(human)8 weeks25 mgoral(human)2 weeks25 mgoral(human)1 year
PubMed
#08

Growth hormone-releasing hormone and growth hormone-releasing peptide as therapeutic agents to enhance growth hormone secretion in disease and aging.

ReviewInfluence1.0
82
The study demonstrated that GH secretagogues like MK-677 may enhance GH secretion in aging and disease, potentially impacting body composition and metabolic health.
25 mgoral(human)7 days4 mg/kgoral(rat)6 weeks10 mgoral(human)2 weeks25 mgoral(human)2 weeks5 mgoral(human)2 weeks25 mgoral(human)8 weeks50 mgoral(human)4 weeks10 mgoral(human)4 days25 mgoral(human)7 days25 mgoral(human)12 months25 mgoral(human)8 weeks25 mgoral(human)2 weeks25 mgoral(human)1 year
PubMed
#09

Effects of a 7-day treatment with a novel, orally active, growth hormone (GH) secretagogue, MK-677, on 24-hour GH profiles, insulin-like growth factor I, and adrenocortical function in normal young men.

Human
79
The study demonstrated that MK-677 increased GH pulse frequency and serum IGF-I levels in healthy young men without significantly affecting cortisol profiles.
25 mgoral(human)7 days4 mg/kgoral(rat)6 weeks10 mgoral(human)2 weeks25 mgoral(human)2 weeks5 mgoral(human)2 weeks25 mgoral(human)8 weeks50 mgoral(human)4 weeks10 mgoral(human)4 days25 mgoral(human)7 days25 mgoral(human)12 months25 mgoral(human)8 weeks25 mgoral(human)2 weeks25 mgoral(human)1 year
PubMed
#10

Oral administration of growth hormone (GH) releasing peptide-mimetic MK-677 stimulates the GH/insulin-like growth factor-I axis in selected GH-deficient adults.

HumanInfluence1.0
70
Researchers observed that MK-677 significantly increased serum IGF-I and growth hormone levels in GH-deficient adults, indicating its potential to stimulate the GH/IGF-I axis.
25 mgoral(human)7 days4 mg/kgoral(rat)6 weeks10 mgoral(human)2 weeks25 mgoral(human)2 weeks5 mgoral(human)2 weeks25 mgoral(human)8 weeks50 mgoral(human)4 weeks10 mgoral(human)4 days25 mgoral(human)7 days25 mgoral(human)12 months25 mgoral(human)8 weeks25 mgoral(human)2 weeks25 mgoral(human)1 year
PubMed
Safety

Safety & Handling

Research Gaps

There is a lack of long-term human trials assessing the chronic effects of MK-677 on health outcomes, particularly regarding its impact on bone density at various sites beyond the femoral neck and its potential side effects. Additionally, the specific mechanisms by which MK-677 alters intramuscular androgenic hormone and receptor concentrations remain unclear, necessitating further investigation into its physiological effects in diverse populations.

Solubility

MK-677 is soluble in DMSO and ethanol but has limited solubility in water.

Storage & Handling

Lyophilized

Stable for 2+ years at -20°C, 12 months at 4°C

Reconstituted

Use within 14 days when refrigerated at 4°C

Avoid

Avoid repeated freeze-thaw cycles, direct light

Solvent

Bacteriostatic water or sterile saline recommended

Safety information is derived from published research and may not reflect all known risks. This is not medical advice.

Legal Status

Legal Status

🇩🇪DE

Not approved as a medicinal product. Not a controlled substance. Sale as research chemical is a legal grey area.

🇺🇸US

Not approved by the FDA for any medical use. Not scheduled by the DEA.

🇦🇺AU

Not approved by the TGA. Considered a Schedule 4 substance, requiring prescription for therapeutic use.

🇬🇧UK

Not approved by the MHRA for medical use. Sale for research purposes only.

Legal status information is provided for general reference only and may not reflect the most current regulatory changes. Always verify with official government sources before making any decisions.

Community Insights

Community Insights

Publications per Year

30 total
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Pricing

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Mechanism

Tools

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Mechanism

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Legal Disclaimer

This page is for informational and research purposes only. All information is based on published scientific literature and does not constitute medical advice, diagnosis, or treatment recommendations. Many substances listed may not be approved for human use and may be subject to drug regulation laws (e.g., AMG in Germany, FDA in the US). PepStack does not encourage the use of any substance on humans. Always consult a qualified healthcare professional before making any health-related decisions. Use of this information is entirely at your own risk. PepStack assumes no liability for the accuracy, completeness, or timeliness of the content provided. Full disclaimer