Ibutamoren, also known as MK-677, is an oral growth hormone-releasing peptide (GHRP).  Unlike Ipamorelin, it's taken by mouth and remains active for roughly 24 hours.  It increases growth hormone levels, energy, lean muscle mass, and strength resulting in improved sleep & muscle recovery.  It can also help decrease fat by stimulating the production of insulin-like growth factor (IGF-1).  MK-677 works by stimulating the pituitary gland which results in increased growth hormone production.  Over time, the body repairs itself, and the aging process is slowed down.  MK-677 also increases ghrelin, the "hunger hormone."  This side effect tends to lessen when taken at bedtime.