Ibutamoren () (developmental code names MK-677, MK-0677, LUM-201, L-163,191; former tentative brand name Oratrope) is a potent, long-acting, orally-active, selective, and

non-peptide Within the fields of molecular biology and pharmacology, a small molecule or micromolecule is a low molecular weight (≤ 1000 daltons) organic compound that may regulate a biological process, with a size on the order of 1 nm. Many drugs are ...

agonist of the ghrelin receptor and a growth hormone secretagogue, mimicking the

growth hormone Growth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in h ...

(GH)-stimulating action of the endogenous

hormone A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are require ...

ghrelin Ghrelin (; or lenomorelin, INN) is a hormone produced by enteroendocrine cells of the gastrointestinal tract, especially the stomach, and is often called a "hunger hormone" because it increases the drive to eat. Blood levels of ghrelin are hi ...

. It has been shown to increase the secretion of several hormones including GH and

insulin-like growth factor 1 Insulin-like growth factor 1 (IGF-1), also called somatomedin C, is a hormone similar in molecular structure to insulin which plays an important role in childhood growth, and has anabolic effects in adults. IGF-1 is a protein that in humans ...

(IGF-1) and produces sustained increases in the plasma levels of these hormones without affecting cortisol levels.

Effect on lean mass

Ibutamoren has been shown to sustain activation of the GH–IGF-1 axis and to increase

lean body mass Lean body mass (LBM), sometimes conflated with ''fat-free mass'', is a component of body composition. Fat free mass (FFM) is calculated by subtracting body fat weight from total body weight: total body weight is lean plus fat. In equations: :LBM&n ...

with no change in total fat mass or

visceral fat Adipose tissue, body fat, or simply fat is a loose connective tissue composed mostly of adipocytes. In addition to adipocytes, adipose tissue contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, vascular e ...

. It is under investigation as a potential treatment for reduced levels of these hormones, such as in children or elderly adults with

growth hormone deficiency Growth hormone deficiency (GHD), or human growth hormone deficiency, is a medical condition resulting from not enough growth hormone (GH). Generally the most noticeable symptom is that an individual attains a short height. Newborns may also prese ...

, and human studies have shown it to increase both muscle mass and bone mineral density, making it a promising potential therapy for the treatment of frailty in the elderly. As of June 2017, ibutamoren is in the

preclinical In drug development, preclinical development, also termed preclinical studies or nonclinical studies, is a stage of research that begins before clinical trials (testing in humans) and during which important feasibility, iterative testing and drug ...

stage of development for growth hormone deficiency.

Effect on sleep architecture

In a small study of 14 subjects, MK-677 dosed at 25mg/day at bedtime was shown to increase REM sleep by 20% and 50% in young and older subjects respectively. Treatment with MK-677 also resulted in an approximate 50% increase in stage IV sleep in young subjects.

Non-research use

Since MK-677 is still an Investigational New Drug, it has not yet been approved to be marketed for consumption by humans in the United States. However, it has been used experimentally by some in the bodybuilding community. Since it chemically mimics the hormone

, it functions as a

neuropeptide Neuropeptides are chemical messengers made up of small chains of amino acids that are synthesized and released by neurons. Neuropeptides typically bind to G protein-coupled receptors (GPCRs) to modulate neural activity and other tissues like the ...

in the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...

and crosses the blood-brain-barrier. According to some recent research and discussion, there is a concern that its particularly longer half-life might over-stimulate the ghrelin receptors in the brain.

References

External links

Ibutamoren - AdisInsight

MK-677 and A Potential Dementia Link - Loungecity.orgGhrelin Over-Stimulation, ''Molecular Psychiatry'' Study - Nature.org
{{GH/IGF-1 axis signaling modulators 4-Phenylpiperidines Anti-aging substances Experimental drugs Ghrelin receptor agonists Growth hormone secretagogues Indolines Spiro compounds Orphan drugs

Effect on lean mass

Effect on sleep architecture

Non-research use

See also

References

External links