In people who took the placebo, IGF-I didn’t go up much, and their muscle energy recovery didn’t link to IGF-I — meaning the connection only showed up when the drug raised IGF-I.
Scientific Claim
In obese adults with reduced GH, the association between IGF-I and phosphocreatine recovery was not observed in the placebo group, suggesting the relationship is driven by tesamorelin-induced IGF-I elevation rather than natural variation.
Original Statement
“Univariate regression analysis among all evaluable paired MRS data (n = 20 pairs) revealed a significant positive relationship between increases in IGF-I and improvements in ViPCr (R=0.56; P=.01). Figure 2 shows placebo-treated subjects (n=11) and tesamorelin-treated subjects (n=9).”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The claim is inferred from subgroup data and is appropriately framed as an observation, not a causal assertion. The language reflects the data without overstatement.
Evidence from Studies
Supporting (1)
The effects of tesamorelin on phosphocreatine recovery in obese subjects with reduced GH.
The study found that when obese people with low growth hormone took a drug called tesamorelin, their IGF-I levels went up and their muscle energy recovery improved — but in people who took a placebo, neither happened. So the link between IGF-I and better energy recovery seems to come from the drug, not just natural differences.