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MK-677

Ibutamoren · Ibutamoren Mesylate · L-163191 · MK677

GH SecretagoguePhase II

MW: 624.8g/mol
Formula: C28H40N4O8S2

MK-677, also known as ibutamoren, is an orally active growth hormone secretagogue that mimics the action of ghrelin, a hormone that stimulates growth hormone release. Researchers primarily study MK-677 for its potential to reverse catabolic states and enhance body composition by increasing growth hormone and insulin-like growth factor I (IGF-I) levels. Key findings indicate that MK-677 can improve nitrogen balance during caloric restriction and stimulate bone turnover in elderly populations, with significant increases in markers of bone formation and resorption. Current research continues to explore its effects on muscle mass, bone density, and various biomarkers in different demographics, highlighting its potential applications in both clinical and athletic settings.

Chemical Profile

Chemical Structure

Formula	C28H40N4O8S2
Molecular Weight	624.8 g/mol
CAS Number	159752-10-0
PubChem CID	6450830
ChEMBL ID	CHEMBL4520674

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 GH-releasing hormone (GHRH) signaling pathway. This increase in GH subsequently elevates serum levels of insulin-like growth factor I (IGF-I), which mediates anabolic processes such as protein synthesis and bone turnover via the IGF signaling pathway. While MK-677's exact mechanism remains partially understood, it is known to enhance nitrogen balance and promote somatic growth, particularly in catabolic states.

Research

34 Research Publications

1,913

Total Citations

Human/RCT

3.4

Avg. Influence

2025

Latest

Sort

Filter

01Top

#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

278

The study demonstrated that daily administration of MK-677 significantly increased pulsatile GH release and serum IGF-I concentrations in healthy elderly subjects.

25 mgoral(human)7 days10 mgoral(human)4 days50 mgoral(human)4 days10 mgoral(human)2 weeks25 mgoral(human)2 weeks5 mgoral(human)2 weeks25 mgoral(human)8 weeks25 mgoral(human)8 weeks25 mgoral(human)12 months10 mgoral(human)2 weeks25 mgoral(human)8 weeks25 mgoral(human)8 weeks25 mgoral(human)12 months25 mgoral(human)12 months

PubMed

02Top

#02

Oxindole derivatives as orally active potent growth hormone secretagogues.

AnimalInfluence1.0

231

The study demonstrated that the oxindole derivative SM-130686 exhibited potent GH-releasing activity and improved pharmacokinetic profiles in rats.

PubMed

03Top

#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

171

The study demonstrated that MK-677 increased GH secretion, fat-free mass, and energy expenditure in healthy obese males over two months.

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

125

Researchers observed that MK-677 acted as an agonist at the ghrelin receptor, demonstrating high potency in activating various signaling pathways.

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

The study demonstrated that MK-677 significantly improved nitrogen balance in healthy human volunteers during caloric restriction, indicating its potential role in reversing diet-induced catabolism.

Key findings

01MK-677 improved nitrogen balance during caloric restriction, reversing diet-induced protein loss.
02Participants taking MK-677 had higher levels of insulin-like growth factor-I (IGF-I) compared to those on placebo.
03The study indicated that MK-677 was well tolerated with no significant adverse effects reported.

PubMed

#06

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

Human

The study demonstrated that prolonged MK-677 treatment improved sleep quality in both young and older adults by increasing REM sleep duration.

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

The study demonstrated that MK-677 combined with alendronate mitigated the reduction in bone formation and enhanced bone mineral density at the femoral neck in postmenopausal osteoporotic women.

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

The study demonstrated that growth hormone secretagogues like MK-677 could enhance GH secretion in aging and disease, potentially improving body composition.

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

Researchers observed that MK-677 administration increased GH pulse frequency and serum IGF-I levels without significantly altering cortisol profiles in healthy young men.

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.

Human

Researchers observed that MK-677 administration significantly increased GH and IGF-I levels in GH-deficient adults, suggesting its potential role in managing GH deficiency.

PubMed

Safety

Safety & Handling

Research Gaps

There is a lack of long-term human trials assessing the chronic effects of MK-677 on various health parameters, particularly its impact on bone density at sites other than the femoral neck, and the potential long-term consequences of altered serum lipids and liver enzymes remain unclear. Additionally, the mechanisms underlying the desensitization to GH stimulation observed in animal studies after prolonged MK-677 administration have not been thoroughly investigated in human subjects.

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

🇩🇪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

Publications per Year

30 total

Pricing

Price Comparison

BESTRuo BioUS
25mg
$68.00
Price/mg
$2.72/mg
View
MoglabsUS
25mg
$68.00
Price/mg
$2.72/mg
View
Peptide ProsUS
25mg
$79.00
Price/mg
$3.16/mg
View
Nextech LabsUS
25mg
$100.00
Price/mg
$4.00/mg
View
Peptides IrelandEU
12.5mg
$59.40
Price/mg
$4.75/mg
View

Vendor	Amount	Price	Price/mg	Link
BESTRuo BioUS	25mg	$68.00	$2.72/mg	View
MoglabsUS	25mg	$68.00	$2.72/mg	View
Peptide ProsUS	25mg	$79.00	$3.16/mg	View
Nextech LabsUS	25mg	$100.00	$4.00/mg	View
Peptides IrelandEU	12.5mg	$59.40	$4.75/mg	View

Top 5 of 14 offers from 13 vendors. Prices updated daily.

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Mechanism

Tools

Reconstitution Calculator

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Serum Level Visualizer

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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