Ibutamoren
In the stimulating scenario of GH production, the long-term safety of
treatment with growth hormone (GH) is an area of much debate. Healthy
elderly people who took the MK-677 mimetic experienced a sustained
increase in the amplitude of pulsatile GH and IGF-I secretion to the
levels seen in young adults [38].
GH reduces abdominal visceral fat (GVA) in GH deficient and obese
adults, postmenopausal women, but not in normal elderly people. Despite
the increased GH levels, MK-677 did not affect GAV, perhaps because its
combined orexigenic and adipogenic effects neutralized the lipolytic
effects of the GH increase. Finally, although MK-677 did not reduce GVA,
it did reduce LDL levels in 12 months and the unobserved effect on GH in
normal elderly people [38].
In a randomized clinical trial, ibutamoren for 12 months was well
tolerated and increased GH secretion and fat-free mass, but not muscle
strength in healthy elderly people. However, development was halted
because ibutamoren was associated with the risk of heart failure in a
randomized study to examine safety and efficacy in patients with hip
fractures [38].