Improves body composition: Several short-term clinical studies have found that MK-677 can positively impact body composition in test subjects. Notably:
A two-month study by Svensson et al. (1998) found that MK-677 helped increase GH levels and preserve levels of fat-free mass (FFM) when administered to twenty-four obese males while dieting. During the study, test subjects were assigned to receive either MK-677 25 mg or a placebo daily for 8 weeks.
Those who received MK-677 experienced a 40 percent increase in serum insulin-like growth factor I (IGF-I) and a significant increase in serum IGF-binding protein-3, especially during the second and eighth weeks. According to the researchers, MK-677 treatment resulted in sustained increases in lean body mass and a temporary increase in basal metabolic rate, levels suggesting that further study was needed to see if a higher dose of MK-677 or a longer treatment period would affect levels of body fat [7].
Enhances quality and duration of sleep: In 1997, Copinschi et al. found that MK-677 improved the quality and duration of sleep when administered to eight young test subjects. The study involved eight young test subjects aged 18-30 years participating in three treatment periods lasting seven days each.
The test subjects were randomly assigned to receive a bedtime dose of either MK-677 (5 and 25 mg) or placebo. Those who received MK-677 experienced a “50% increase in the duration of stage IV sleep and a more than 20% increase in REM sleep” compared to placebo. Researchers concluded that MK-677 may “simultaneously improve sleep quality and correct the relative hyposomatotropism of senescence” [8].
Aids bone formation and resorption: Other studies have investigated the effects of MK-677 on bone formation and resorption:
A 1999 paper published by Murphy et al. as “MK-677 Study Group” reported the findings from three separate studies into the effects of MK-677 on bone turnover in healthy and functionally impaired elderly adults.
The first study involved 32 healthy seniors who were assigned to receive either MK-677 at 10 mg or 25 mg, or placebo.
The second study involved 50 healthy adults aged 65-85 who received either MK-677 at 25 or 50 mg/day or placebo, while the third study involved 105 elderly patients with functional impairment aged 65-94 who received MK-677 (5, 10, or 25 mg) or placebo. According to the authors, “once-daily dosing of MK-677 stimulates bone turnover in elderly adults” [9].
A randomized, double-blind, parallel, and placebo-controlled trial by Svensson et al. (1999) assigned 24 obese patients to receive either MK-677 25 mg or placebo. Researchers found that short-term MK-677 treatment led to increases in markers of bone resorption and formation but suggested that further long-term studies were needed to gauge MK-677’s effect on bone mass [10].
Experimental treatment of Alzheimer’s Disease: A 2008 study by Sevigny et al. examined whether MK-677 could slow the rate of progression of symptoms in patients with Alzheimer’s Disease (AD). The researchers were operating on the belief that MK-677's ability to raise IGF-1 levels would clear amyloid beta plaques from the nervous systems of AD subjects, thus slowing the disease’s progression.
The study involved a total of 563 patients with mild to moderate AD who were randomly assigned to receive MK-677 25 mg or placebo daily for 12 months. 416 patients completed the study, and those in the MK-677 group experienced a 60 percent increase in serum IGF-1 levels at six months and a 72.9 percent increase after one year. Unfortunately, scores from the diagnostic tests used to assess the volunteers found that MK-677 was “ineffective at slowing the rate of progression of AD” [11].