← Back to Methodology
RQS Scoring Log

Ibutamoren

Growth Hormone· Observational· Scored May 2026· View compound profile →
63 /100
Moderate Evidence
7 dimensions · 100 points total · Methodology by PeptideClear
Dimension Breakdown
DimensionScoring NotesScore
Study Design
Multiple human studies including some randomized trials, though most are observational or open-label. Phase II studies for GH deficiency and muscle wasting. Merck discontinued development despite promising signals.
15 / 25
Sample Size
Studies range from 24 to ~300 participants. Nass et al. 2008 (JCEM) enrolled 65 adults. Chapman et al. enrolled ~32. Moderate cumulative sample.
12 / 20
Replication
Replicated by multiple independent academic groups. GH/IGF-1 elevation is one of the more consistently replicated non-approved GH secretagogue findings in humans.
15 / 20
Journal Impact Factor
Publications in JCEM (IF ~6.5), NEJM (Chapman 1996, IF ~96), and Annals of Internal Medicine. The Chapman 1996 NEJM paper is the standout.
8 / 15
Funding Independence
Mix of Merck-funded pharmaceutical trials and independent academic replication. The NEJM and later JCEM studies include academic investigators.
7 / 10
Population Diversity
Studied in elderly, GH-deficient adults, and hip fracture patients. Moderate diversity but mostly older adults with specific conditions. Limited ethnic diversity reported.
3 / 5
Researcher h-Index
Roy Smith (Merck), Michael Thorner (UVA) — both prominent endocrinologists with h-Indexes 20+. Rounded to 4 given mixed authorship across studies.
3 / 5