Peptides > MK-677 (Ibutamoren)

MK-677 (Ibutamoren)

MK-677, alternatively known as Ibutamoren or Oratrope, is an orally administered compound that acts as a specific agonist for the ghrelin receptor. Scientific investigations have indicated that Ibutamoren facilitates the secretion of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) without influencing cortisol levels. It is currently under examination as a potential therapeutic intervention for conditions such as growth hormone deficiency, muscle and bone degeneration, appetite enhancement, and Alzheimer’s disease. Notably, research involving MK-677 in mice demonstrated the potential to delay the onset of Alzheimer’s disease, even in genetically predisposed mice, when initiated prior to significant amyloid beta accumulation. Additionally, MK-677 research has exhibited encouraging outcomes in the enhancement of sleep quality.

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1. MK-677 (Ibutamoren) Overview


2. Molecular Structure of MK-677


3. Research on MK-677

MK-677 (Ibutamoren) Overview

MK-677 as a Growth Hormone Secretagogue and Ghrelin Mimetic

MK-677, also referred to as Ibutamoren and Oratrope, is a potent and orally active compound that selectively activates the ghrelin receptor. Unlike ghrelin, Ibutamoren is not a peptide and lacks structural similarities to it. Studies indicate that Ibutamoren stimulates the secretion of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) while leaving cortisol levels unaffected. Consequently, Ibutamoren activates the GH axis, promoting an increase in lean body mass. It is currently being researched for its potential in treating conditions such as growth hormone deficiency, muscle and bone wasting, and appetite stimulation. Ibutamoren is appreciated for its extended half-life and efficient oral absorption, with human studies demonstrating elevated IGF-1 levels for up to 24 hours following a single dose.

MK-677 and Its Classification 

MK-677 is often categorized alongside selective androgen receptor modulators (SARMs), although it does not fit neatly into this classification. Notably, MK-677 is neither a SARM nor a peptide. Instead, it is a complex synthetic chemical propanamide derivative that acts as a ghrelin receptor agonist. When examining its effects, MK-677 aligns best with the family of growth hormone secretagogues. Similar to compounds like GHRP-2, GHRP-6, hexarelin, and ipamorelin, MK-677 binds to the ghrelin/growth hormone secretagogue receptor, boosting GH release while maintaining the normal pulsatile patterns of GH fluctuation.

Advantages of MK-677 Over SARMs

One significant advantage of MK-677 is its distinction from SARMs. SARMs have the potential to impact natural androgen production, leading to lowered testosterone levels. Consequently, their administration requires careful regulation, including cycling on and off, to prevent suppression of natural androgen production. MK-677, however, does not necessitate such precautions.

Molecular Structure of MK-677 (Ibutamoren)

Molecular Formula: C27H36N4O5S
Molecular Weight: 528.7 g/mol
PubChem CID: 9939050
CAS Number: 159634-47-6
Synonyms: MK-0677, Oratrope, Ibutamoren, L-163,191

Research on MK-677

MK-677 and Somatopause: The progressive decline of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) with age is known as somatopause. It leads to changes in body composition and muscle function, especially in the elderly. While men at 70 years produce only about 60% of the GH they did at 18, estrogen and progesterone can elevate GH and IGF-1 levels in women, mitigating the effects of somatopause.

MK-677 and Body Composition: MK-677 shows promise in potentially slowing somatopause progression. In a two-year controlled trial, daily oral MK-677 administration (25 mg) significantly increased GH and IGF-1 levels, resulting in a modest weight gain of approximately 2 kg without affecting strength or fat mass. It also improved bone density and had some effects on cholesterol levels. MK-677 could potentially address negative nitrogen balance caused by low protein intake, offering clinical benefits in various health conditions, including sarcopenia.

MK-677 and Bone Density: Research in both young obese males and elderly individuals indicates that MK-677 can influence bone remodeling, potentially improving bone strength and resistance to fractures, particularly when combined with weight training. Some studies suggest positive effects on gait speed and fall reduction in elderly patients with hip fractures. However, further research is needed to fully understand its impact.

MK-677 and Neurological Function: IGF-1 plays a role in clearing amyloid beta from the central nervous system, a key factor in Alzheimer’s disease (AD). While MK-677 increases IGF-1 levels in elderly patients, it doesn’t alter AD progression once diagnosed. Animal studies, though, suggest that MK-677 could be a preventative measure, reducing amyloid beta deposition and neuron loss when started before significant accumulation occurs.

MK-677 and Sleep: MK-677 has significant effects on sleep, particularly in older adults, increasing REM sleep duration and potentially aiding in muscle recovery, brain function, and development. Prolonged REM sleep could offer valuable insights into the function of sleep.

MK-677 and Heart Health: Aging leads to a decline in stem cell function, including endothelial progenitor cells (EPCs) important for blood vessel regeneration. Increased GH levels, as influenced by MK-677, may reverse the age-related decline in EPCs, potentially reducing the risk of heart disease. Additionally, GH treatment can increase nitric oxide levels, which regulate blood vessel health and blood pressure, potentially benefiting cardiovascular health.

MK-677 Summary: MK-677, a non-peptide ghrelin/growth hormone secretagogue agonist, elevates GH and IGF-1 levels in animal and human testing. It appears safe with minimal side effects but is not yet approved for widespread human use. Research indicates potential benefits in appetite regulation, body composition, muscle strength, cardiac health, and neurological function. Long-term use as a preventative measure may offer the most significant advantages, especially in the context of age-related diseases.

Article Author

The above literature was researched, edited and organized by Dr. Logan, M.D. Dr. Logan holds a doctorate degree from Case Western Reserve University School of Medicine and a B.S. in molecular biology.


The product information featured on this website pertains exclusively to in-vitro studies. In-vitro studies, also known as ‘in glass’ studies, are conducted outside of living organisms. It’s important to emphasize that these products do not constitute medicines or drugs and have not received FDA approval for the prevention, treatment, or cure of any medical conditions, ailments, or diseases. It is crucial to note that the introduction of these products into the bodies of humans or animals is strictly prohibited by law.