What is MK 677?

MK 677, sometimes called nutrabol or ibutamoren, is a growth hormone secretagogue and a selective agonist for the ghrelin receptor. Researchers have conducted laboratory tests with MK 677 to determine its usefulness in treating issues like obesity, anorexia, dementia, Alzheimer’s, and other forms of age-based cognitive decline.


What is a Selective Agonist?

An agonist is a chemical compound which binds to its respective receptor and triggers a biological process. A selective agonist is a compound designed to only target specific receptors. In this way, one can administer substances like MK 677 without triggering processes which are not desired.

MK 677 works on the ghrelin receptor, or the growth hormone secretagogue receptor. Ghrelin is a natural peptide hormone that regulates appetite and the body’s regulation and use of energy. The ghrelin receptor binds with ghrelin to regulate body weight, energy, appetite and alike.


What is a Growth Hormone Secretagogue?

To begin, a secretagogue is a chemical which causes the secretion of a certain substance. Secretagogues are not limited to growth hormones. Histamines for example are a type of secretagogue.

Growth hormone secretagogues (GHSs) are a type of drug which triggers the secretion of growth hormones (GHs). GH is a naturally occurring peptide hormone responsible for tissue growth and cell reproduction. The pituitary gland manufactures GH and the hormone is responsible for the maintenance of muscle and tissue. However, with age the production of GH begins to drop away.

MK 677 itself deals specifically with the ghrelin receptor. Studies done on the ghrelin hormone and growth hormone secretagogue receptor (GHSR) have found that ghrelin levels are closely tied to feeding behavior, memory, learning, and motivation (Edwards et al, 2017).[1] That said, these topics need more study. But an intricate relationship between ghrelin and feeding behaviors has still been established.


What Can MK 677 Do?

MK 677 is sometimes referred to as a ghrelin mimetic, or possessing the same effects as natural ghrelin, and is also considered a GHS. As such, researchers have studied and tested MK 677 for the promotion of growth hormone production in older patients. MK 677 is also orally active, so it can be taken without having to use injections.

A study published in 2008 examined the effects of introducing MK 677 to young adults and elderly adults to test for an increase in GH levels. The research hoped to find that boosting GH production via MK 677 would prevent the loss of fat-free mass (FFM) and reduce abdominal visceral fat (AVF). The hope was that these results would boost bodily strength and functionality. The study found that boosting GH production through MK 677 increased body FFM but did not improve muscle strength. Body mass improved as whole though. The study also found that GH production boosted insulin resistance and curbed contributing factors to sarcopenia in the elderly. An increase in appetite was an adverse side effect, although this eventually subsided. This increase in appetite could potentially aid in the treatment of anorexia (Nass et al, 2008)[2].

An article published in 2011 compiled several studies on the use of ghrelin to treat a wide variety of diseases and conditions. One of the aspects that this article examined was the use of ghrelin mimetics, including MK 677. The research found that studies had shown that MK 677 improved the bone mineral density of post-menopausal women. MK 677 could also improve insulin-like growth factor 1 (IGF 1) levels in young adults. Introducing MK 677 also showed great potential in treating cancer cachexia, or the wastage of body mass from cancer. This was due to MK 677 boosting appetite. However, the study still found that there was little improvement to independence and quality of life in the elderly despite improvements to body mass (Nass et al, 2011)[3].

MK 677 still needs further research, but the possibilities are there. It has shown potential in treating diseases of bodily atrophy, eating disorders, and has been investigated for treating dementia and Alzheimer’s. However, those studies have yet to yield many results, but more research is still possible. There are also so far very few known side effects except for increased appetite and possible numbness in the extremities.





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