Tesamorelin is one of the few research peptides that cleared a full FDA review. Sold as Egrifta (originally by Theratechnologies, developed under the code TH9507), it was approved in 2010 to reduce excess abdominal fat in people with HIV-associated lipodystrophy. That makes it unusual on a site like this: most of what we cover is preclinical or grey-market, but tesamorelin has a real Phase 3 program behind it.
What it is
Tesamorelin is a synthetic analog of growth-hormone-releasing hormone (GHRH). The native molecule is a 44-amino-acid peptide that signals the pituitary to release growth hormone. Native GHRH is fragile, broken down quickly in the blood by the enzyme dipeptidyl peptidase-4 (DPP-4). Tesamorelin adds a hexenoyl group to the N-terminal tyrosine, which slows that degradation and gives the molecule enough staying power to be a usable drug.
It belongs to the GHRH-analog family. Functionally it is a growth-hormone secretagogue: instead of injecting growth hormone itself, it prompts the pituitary to release the body's own GH in a roughly normal pulsing pattern, which in turn raises insulin-like growth factor 1 (IGF-1).
What the research shows
The approval rests on a Phase 3 program in HIV patients with abdominal fat accumulation. The pivotal trial, published in the New England Journal of Medicine by Falutz and colleagues, randomized 412 patients to 2 mg of daily subcutaneous tesamorelin or placebo for 26 weeks. Visceral adipose tissue, measured by CT, fell about 15% in the treated group and rose about 5% on placebo. Triglycerides improved as well. (Falutz et al., NEJM 2007)
A later regulatory review of the combined trial data (Egrifta) found visceral fat reductions in the range of roughly 12–20% versus placebo across studies. The same review flags two things buyers rarely hear about. The effect is reversible: when people stopped the drug, visceral fat came back, increasing by as much as 25% over the following months. And adverse events were common, including injection-site reactions, joint and muscle pain, and fluid retention. Long-term cardiovascular, diabetes, and cancer risks were noted as needing more study. (CADTH/NCBI Clinical Review)
Separate from the fat indication, tesamorelin has been tested for brain function. A randomized controlled trial in Archives of Neurology gave 1 mg nightly for 20 weeks to 152 older adults, some with mild cognitive impairment. GHRH treatment raised IGF-1 by about 117% and showed a favorable effect on executive function, with a weaker signal for verbal memory. (Baker et al., Arch Neurol 2012) This is interesting early evidence, not an approved use, and it has not led to a cognition indication.
Regulatory and anti-doping status
Tesamorelin is FDA-approved, but only for HIV-associated lipodystrophy. Everything else, including any anti-aging, body-composition, or cognitive use, is off-label or unapproved. Material sold as research powder is not a substitute for the prescription product and is labeled research-use-only by sellers for a reason.
In sport, tesamorelin is banned. The World Anti-Doping Agency lists GHRH analogs under category S2 (peptide hormones, growth factors, related substances and mimetics), prohibited at all times. (WADA Prohibited List)
The quality and testing angle
If you are looking at research-grade tesamorelin rather than the pharmacy product, identity and purity are the whole game. A peptide this specific can be under-filled, degraded, or simply not what the label says, and you cannot tell by looking. A third-party certificate of analysis showing the actual peptide identity (typically by mass spec) and purity (by HPLC), tied to the specific lot you receive, is the minimum worth asking for. peptideone aggregates vendor COAs and independent rater signals so you can compare what sellers actually publish instead of taking marketing claims at face value.
Nothing here is medical or dosing advice. Tesamorelin is a prescription drug for a specific condition; research material is not approved for human consumption, and the figures above describe published studies, not recommendations.