WHAT IS IT?
Ibutamoren (MK-677) is a growth hormone secretagogue and ghrelin receptor agonist. It increases the endogenous secretion of GH and IGF-1. A growth hormone secretagogue is simply a substance that signals the pituitary gland in your body to secrete more growth hormone.
Much like SARMs, it is non-steroidal, but contrary to popular belief, MK-677 is not a SARM in any capacity, despite commonly being thrown into that category. MK-677 will not negatively affect natural testosterone levels or endocrine function in any capacity at all, as it does not suppress any male sex hormones.
WHAT ARE THE RESULTS?
In a 12-month study conducted on postmenopausal osteoporotic women, 25 mg of MK-677 per day increased bone mineral density and was well tolerated without any significantly concerning side effects.
Growth hormone (GH) can accelerate lipolysis, and has an anabolic effect in muscle tissue by increasing insulin-like growth factor (IGF)-I and nitrogen retention. In a 2-month study on 24 healthy obese men using 25 mg of MK-677 per day, 3 kg of lean muscle mass was gained in the MK-677 treated group compared to the placebo group. According to a DEXA scan, total body fat did not change during the study, equating to a gain of 6.62 pounds of muscle in the MK-677 treated group.
Due to its positive effect on body composition, there is a case to make in regards to MK-677 being a possible treatment for obesity. Ibutamoren exhibits blatantly anti-catabolic properties, one of which is its ability to retain nitrogen even in a steep caloric deficit. MK-677 reversed nitrogen wasting caused by the caloric deficit, suggesting that if these short-term anabolic effects are sustainable, it could be a viable treatment for those experiencing chronic disease, or other muscle wasting catabolic conditions.
Natural Growth Hormone secretion downregulates with age, consequently lowering serum IGF-1 levels in the body, which results in significant lean muscle catabolism and increased mortality.
By restoring GH and IGF-1 levels to that of young healthy adults, it is likely that a significant amount of muscle and bone degradation could be prevented entirely.
IGF-1 has been shown to affect follicular proliferation and differentiation, remodeling of tissue, as well as the hair growth cycle itself. More evidence is arising to suggest that IGF-1 plays an important role as a regulator in hair follicle biology. It should be noted that patients with growth hormone (GH) deficiency resulting from defective hormone binding with low serum IGF-1 levels exhibit very sparse hair growth.
MK-677 will almost undoubtedly greatly increase appetite . Besides acting as a potent growth hormone secretagogue, MK-677 is also an oral ghrelin mimetic. Ghrelin is the “hunger hormone” that your stomach secretes in order to regulate your appetite.
Though not reported in the clinical data, anything that increases your GH and IGF-1 levels will increase your lethargy. Regardless if GH/IGF-1 is increased via synthetic gh injections, growth hormone releasing peptides, or growth hormone secretagogues like MK-677, increased levels of lethargy is an expected and common side effect.
Dreams (both lucid and non-lucid) are much more common during the REM cycle of sleep. As sleep affects the regulation of growth hormone (GH), typically, getting a deep and restful sleep is associated with optimal growth hormone secretion, and consequently, more dreaming
A common side effect from elevated GH and IGF-1 levels is water retention.
Increased blood pressure is an indirect side effect resulting from edema, which is one of the most common MK-677 side effects
Although several clinical studies found no change in blood glucose levels, there were a couple studies where MK-677 caused an elevation of fasted blood glucose levels and decreased insulin sensitivity.
Tingly or numb hands/fingers.