Even when accounting for changes in growth hormone levels, these muscles still got bigger, meaning the drug works through other pathways too.
Scientific Claim
In HIV-positive adults with abdominal obesity who responded to tesamorelin with ≥8% VAT reduction, the increase in lean muscle area of the psoas and rectus muscles remained significant after adjusting for IGF-1 changes, indicating that muscle growth is not fully dependent on IGF-1.
Original Statement
“Lean muscle area changes remained significant after adjusting for VAT; only changes in the rectus and paraspinal lean muscles remained highly significant (p<0.005) after adjusting for changes in IGF-1.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
definitive
Can make definitive causal claims
Assessment Explanation
The RCT design with multivariate adjustment supports causal inference. The persistence of significance after IGF-1 adjustment justifies definitive language for these specific muscles.
Evidence from Studies
Supporting (1)
The Growth Hormone Releasing Hormone Analogue, Tesamorelin, Decreases Muscle Fat and Increases Muscle Area in Adults with HIV
The study found that a drug called tesamorelin helped HIV patients with belly fat gain more muscle in their abdomen and back, even though we don’t know if a hormone called IGF-1 was involved — so it hints that muscle growth might happen without IGF-1, but doesn’t prove it.