The short version
Tesamorelin is the only growth hormone-releasing peptide that has earned full FDA approval, and it did so on the back of strong, properly conducted phase 3 trials. It targets something very specific: visceral fat, the deep abdominal fat that wraps around organs and drives metabolic disease. Unlike GLP-1 drugs that reduce fat broadly, tesamorelin selectively shrinks the visceral depot while leaving subcutaneous fat largely untouched. That precision is what makes it interesting to researchers and clinicians working on metabolic health.
How it works — in plain English
Rather than injecting growth hormone directly (which bypasses the body's own regulatory system), tesamorelin signals your pituitary gland to release growth hormone in the body's natural pulsatile rhythm. That released GH then raises IGF-1, which activates fat-burning enzymes in visceral fat cells. Visceral fat cells turn out to be significantly more sensitive to this signal than subcutaneous fat, which explains why the effect is so specific to deep belly fat.
What the research actually shows
The approval was built on two pivotal phase 3 trials totalling over 800 participants, with CT-verified visceral fat measurements at every step — rigorous methodology that most peptides never come close to.
Beyond the fat loss itself, the trials showed significant improvements in triglycerides and total cholesterol. A more recent Harvard-led trial found that tesamorelin reduced liver fat by 37% at 12 months — a finding that has generated considerable interest for its potential applications beyond the original approved population.
Approved for one group — interesting for others
The FDA approval is specifically for HIV-associated lipodystrophy, where antiretroviral therapy causes visceral fat accumulation. Clinicians can legally prescribe it off-label for other metabolic purposes, but the long-term data outside that population is thinner. Any off-label use is a decision for you and a qualified clinician, not something to pursue independently.