Ibutamoren, also commonly known by its research designation MK-677, is a growth hormone secretagogue. More specifically, it belongs to the GHRP (Growth Hormone Releasing Peptides) class. These drugs all mimic the activity of ghrelin on the growth hormone secretagogue receptor la (GHSRIa), which stimulates the pulsatile secretion of this hormone from the pituitary. Ibutamoren is considered a third generation GHRP, mostly for its refined oral bioavailability. In human studies, it has been shown to significantly elevate serum GH and IGF-1 levels in both the young and elderly, increase fat-free mass and energy expenditure, improve sleep quality, and reduce diet-induced catabolism. In the fitness community, this drug is most commonly used for muscle gain and fat loss, as well as an appetite stimulant.
Ibutamoren MK 677
|Dose for men||
25-50mg / day (up to 10 weeks)
45 x 25mg capsules
The activity profile of ibutamoren would be most closely compared to that of GHRP-6. Both drugs are potent stimulators of growth hormone release. However, neither is selective for this activity. As with GHRP-6, ibutamoren is likely to also result in mild increases in ACTH (adrenocorticotropic hormone), cortisol, and prolactin levels. Related spillover side effects are always possible, though not especially common or noteworthy with this drug. In most cases the spillover increases in these other hormones are modest, and not outwardly noticeable to the user. Ibutamoren is also a moderately strong appetite stimulant. Be aware that unless diet is controlled, the use of this drug may coincide with a significant increase in daily caloric intake. When diet is controlled, its GH-stimulating properties may support fat loss.
Ibutamoren Mesylate Side Effects (General)
The most common side effects to ibutamoren are an increase in appetite and sleepiness. Also frequently reported are adverse effects typically associated with other types of growth hormone therapy, such as water retention (edema), joint pain (arthralgias), carpal tunnel syndrome, and numbness or tingling in the extremities. Note that the incidence of side effects tends to be lower with GHRP therapy as compared to traditional hGH. This is because GH/IGF-1 release is subject to endogenous synthesis, and as such the drug is less amenable to overdosing.
Ibutamoren Mesylate Side Effects (Impaired glucose tolerance)
Ibutamoren may reduce insulin sensitivity and raise blood sugar levels. This may occur in individuals without preexisting diabetes or impaired glucose tolerance.
Ibutamoren Mesylate Administration
Ibutamoren is given orally.
When used for physique- or performance-enhancing purposes, ibutamoren appears to exhibit its optimum efficacy at a dosage of 10-25 mg daily. This is taken in one dose before sleep. Cycles usually last 3-4 months, though programs of 6 months or longer are not uncommon.