MK-677
Also known as: Ibutamoren
The only growth hormone booster you can take as a pill instead of injecting. Also known as Ibutamoren, it mimics the hunger hormone ghrelin to trigger GH release. Very popular because of the convenience — just swallow a capsule once daily. The major downside is a significant increase in appetite (you will feel hungry), and it stays active for 24 hours so the effects don't switch off. Studied for muscle wasting and bone density but never completed FDA approval.
MK-677 (Ibutamoren) is an orally active growth hormone secretagogue that mimics the action of ghrelin by binding to the ghrelin receptor (GHS-R1a) in the brain. Unlike most GH peptides that require injection, MK-677 is taken as a pill or capsule, making it one of the most convenient options for growth hormone optimization. It is not technically a peptide but a non-peptide ghrelin mimetic that is frequently grouped with GH peptides due to its mechanism.
MK-677 stimulates sustained growth hormone release and significantly elevates IGF-1 levels — studies show 40-60% increases in IGF-1 that persist with daily dosing. Because it activates the ghrelin receptor, it also increases appetite substantially (sometimes intensely), which can be a benefit for hard-gainers or a significant drawback for those trying to lose fat. Its 24-hour half-life means effects persist around the clock, including side effects like water retention and increased appetite.
Typical dosing is 10-25 mg orally once daily, usually before bed. MK-677 has been studied in clinical trials for growth hormone deficiency, muscle wasting, osteoporosis, and age-related frailty. Side effects include water retention, increased appetite, joint pain, numbness in hands, and reduced insulin sensitivity with long-term use. It is not FDA-approved and is classified as an investigational drug.
Dosage
10-25 mg oral once daily
Dosages shown are for research reference only. Always consult a qualified healthcare provider.
Administration
Oral (capsule or liquid)
Shop Research-Grade Peptides
99%+ purity · US-based · third-party lab tested
Getting Started — Here's What You'll Need
Effects
GH Elevation
40-60% increase in IGF-1 levels sustained over 12 months in clinical studies.
Appetite Increase
Strong ghrelin-mimetic effect significantly increases hunger.
Sleep Improvement
May improve sleep quality through enhanced GH pulsatility during rest.
Mechanism of Action
MK-677 (Ibutamoren) is a non-peptide spiropiperidine compound that functions as a potent, orally active agonist of the growth hormone secretagogue receptor type 1a (GHS-R1a). Unlike peptide-based GH secretagogues that require injection, MK-677 is resistant to gastrointestinal degradation and has excellent oral bioavailability, making it unique among compounds that stimulate GH release through the ghrelin receptor.
Upon binding GHS-R1a in the anterior pituitary, MK-677 activates the Gq/11-coupled PLC/IP3/calcium signaling pathway, triggering GH vesicle exocytosis. It also acts on GHS-R1a receptors in the hypothalamus, stimulating GHRH neurons in the arcuate nucleus while suppressing somatostatin tone, further amplifying the GH secretory signal. Importantly, MK-677 preserves the endogenous pulsatile pattern of GH release — it amplifies pulse amplitude rather than creating a flat, sustained elevation.
The 24-hour half-life means a single daily dose maintains elevated GH and IGF-1 levels around the clock. In clinical studies, MK-677 increased IGF-1 levels by 40-60% in elderly subjects, with sustained effects over 12 months without significant tachyphylaxis. However, its ghrelin-mimetic activity also activates hypothalamic appetite circuits (orexigenic neurons expressing NPY/AgRP), producing the notable increase in hunger that many users report. The compound also has mild cortisol-raising effects and can impair insulin sensitivity with prolonged use, likely through sustained GH-mediated antagonism of insulin signaling in peripheral tissues. Despite promising clinical data for muscle wasting and osteoporosis, MK-677 has not completed the FDA approval process.
Regulatory Status
Not FDA approved. Investigated in clinical trials for muscle wasting and osteoporosis but never completed approval. Available as research chemical.
Risks & Safety
Common
increased appetite (often intense), water retention and bloating, tiredness and fatigue, joint pain, numbness in hands.
Serious
raised fasting blood sugar and reduced insulin sensitivity with long-term use, potential to accelerate existing tumour growth.
Rare
significant swelling, carpal tunnel syndrome.
Compare MK-677 With
Research Papers
5Published: March 18, 2023
AI Summary
MK-677 was detected in horse hair for up to 209 days in mane and 358 days in tail after oral administration. Later samples indicated internal incorporation via the bloodstream, supporting long-term detection for doping control.
Published: December 15, 2022
AI Summary
Combined use of LGD-4033 and MK-677 increased body mass and lean mass but also raised fat mass and negatively affected bone, lipids, liver enzymes, and testosterone. The compounds may alter muscle hormone and receptor levels.
Published: September 29, 2022
AI Summary
Ibutamoren is described as a potent, orally active growth hormone secretagogue with significant abuse potential in sports. The paper characterizes MK-0677 and its metabolites in horses for doping control purposes.
Published: July 24, 2022
AI Summary
In vitro and in vivo studies identified 14 metabolites of MK-0677 in horses; an O-dealkylated metabolite offered the longest detection window in urine and plasma. This metabolite is the best analytical target for doping control.
Published: December 14, 2021
AI Summary
Ibutamoren is described as a potent, orally active growth hormone secretagogue with high abuse potential in sports. The paper characterizes metabolites produced by equine liver microsomes to support doping control.
Frequently Asked Questions
What is MK-677?
The only growth hormone booster you can take as a pill instead of injecting. Also known as Ibutamoren, it mimics the hunger hormone ghrelin to trigger GH release. Very popular because of the convenience — just swallow a capsule once daily. The major downside is a significant increase in appetite (you will feel hungry), and it stays active for 24 hours so the effects don't switch off. Studied for muscle wasting and bone density but never completed FDA approval.
What is MK-677 used for?
The only growth hormone booster you can take as a pill instead of injecting. Also known as Ibutamoren, it mimics the hunger hormone ghrelin to trigger GH release. Very popular because of the convenience — just swallow a capsule once daily. The major downside is a significant increase in appetite (you will feel hungry), and it stays active for 24 hours so the effects don't switch off. Studied for muscle wasting and bone density but never completed FDA approval.
What is the dosage for MK-677?
Standard: 10-25 mg oral once daily, typically before bed. Often cycled 8-12 weeks on, 4 weeks off. Some protocols use continuous low-dose (10 mg) for extended periods.
What are the side effects of MK-677?
Common: increased appetite (often intense), water retention and bloating, tiredness and fatigue, joint pain, numbness in hands. Serious: raised fasting blood sugar and reduced insulin sensitivity with long-term use, potential to accelerate existing tumour growth. Rare: significant swelling, carpal tunnel syndrome.
How does MK-677 work?
MK-677 (Ibutamoren) is a non-peptide spiropiperidine compound that functions as a potent, orally active agonist of the growth hormone secretagogue receptor type 1a (GHS-R1a). Unlike peptide-based GH secretagogues that require injection, MK-677 is resistant to gastrointestinal degradation and has excellent oral bioavailability, making it unique among compounds that stimulate GH release through the ghrelin receptor. Upon binding GHS-R1a in the anterior pituitary, MK-677 activates the Gq/11-coupled PLC/IP3/calcium signaling pathway, triggering GH vesicle exocytosis. It also acts on GHS-R1a receptors in the hypothalamus, stimulating GHRH neurons in the arcuate nucleus while suppressing somatostatin tone, further amplifying the GH secretory signal. Importantly, MK-677 preserves the endogenous pulsatile pattern of GH release — it amplifies pulse amplitude rather than creating a flat, sustained elevation. The 24-hour half-life means a single daily dose maintains elevated GH and IGF-1 levels around the clock. In clinical studies, MK-677 increased IGF-1 levels by 40-60% in elderly subjects, with sustained effects over 12 months without significant tachyphylaxis. However, its ghrelin-mimetic activity also activates hypothalamic appetite circuits (orexigenic neurons expressing NPY/AgRP), producing the notable increase in hunger that many users report. The compound also has mild cortisol-raising effects and can impair insulin sensitivity with prolonged use, likely through sustained GH-mediated antagonism of insulin signaling in peripheral tissues. Despite promising clinical data for muscle wasting and osteoporosis, MK-677 has not completed the FDA approval process.
How is MK-677 administered?
MK-677 is administered via oral (capsule or liquid).
What is the half-life of MK-677?
The half-life of MK-677 is 24 hours.
Is MK-677 legal?
Not FDA approved. Investigated in clinical trials for muscle wasting and osteoporosis but never completed approval. Available as research chemical.
Related Peptides
ACE-031
An experimental drug that acts as a 'decoy' to intercept myostatin and other muscle-limiting signals before they reach your muscles. It produced rapid muscle gains in clinical trials without any exercise. However, development was halted because it also accidentally blocked signals needed to maintain healthy blood vessels, causing nosebleeds and visible broken blood vessels. A powerful proof-of-concept that myostatin blocking works, but too dangerous in its current form.
AEDG Peptide
A tetrapeptide (Ala-Glu-Asp-Gly) identical to Epithalon's core active sequence — effectively the same compound. Studied for telomerase activation and pineal gland regulation, promoting melatonin production and potentially slowing cellular aging through telomere maintenance. Part of the Khavinson bioregulator peptide family developed in St. Petersburg.
AICAR
A natural compound that activates your cells' energy sensor — the same pathway that turns on during exercise. Mimics the metabolic effects of endurance exercise at the cellular level, helping with fat burning, glucose uptake, and building more mitochondria. Banned by WADA as a metabolic modulator after detection in professional cycling.
BPC-157
A healing compound made from a protein found in stomach fluid. It's the most studied peptide for tissue repair, with research showing it helps heal tendons, ligaments, muscles, the gut, and other organs. It's stable enough to survive stomach acid, so you can take it either by injection under the skin or by mouth.