Tesamorelin vs Sermorelin
Category
Growth Hormone Axis
Growth Hormone Axis
Class
Synthetic GHRH analog (stabilized 44-amino-acid peptide)
Synthetic GHRH (1-29) analog
Regulatory status
FDA-approved (Egrifta) for HIV-associated lipodystrophy; other uses are off-label or investigational
Historically FDA-approved (Geref), later withdrawn from the US market; not currently an approved medicine
Mechanism
Tesamorelin is a stabilized analog of growth-hormone-releasing hormone (GHRH). Rather than supplying growth hormone directly, it stimulates the pituitary gland to release the body's own growth hormone in a more natural, pulsatile pattern.
Sermorelin reproduces the active portion of natural GHRH, signaling the pituitary to release growth hormone in a pulsatile, physiological pattern.
Evidence summary
Tesamorelin has an unusually strong evidence base for a peptide: multiple randomized, placebo-controlled trials in people with HIV-associated lipodystrophy show consistent reductions in visceral fat, leading to FDA approval. Evidence outside that approved indication, for example a small pilot suggesting cognitive benefits in older adults, is much weaker and not yet confirmed in larger trials.
Sermorelin has a clearer regulatory history than most peptides here, having been approved for diagnostic testing of GH reserve and for pediatric growth hormone deficiency before withdrawal. However, evidence for the wellness and anti-aging uses it is now marketed for is limited, and modern controlled outcome trials in those settings are scarce.
Reported safety
Because tesamorelin is FDA-approved, it has a defined human safety profile from controlled trials. Reported effects relate mostly to its growth-hormone activity, injection-site reactions, joint aches, fluid retention, and increases in blood sugar. It is contraindicated in pregnancy and in people with active cancer or certain pituitary conditions.
During its approved use, sermorelin was generally well-tolerated, with injection-site reactions, flushing, and headache reported most often. Long-term safety in current off-label wellness contexts is less well characterized.