Tesamorelin Peptide: Identity, Structure and Research Record

Tesamorelin is a synthetic analog of human growth hormone-releasing factor (GRF), also called growth hormone-releasing hormone (GHRH), and the active ingredient of the FDA-approved prescription drug Egrifta. Sources: FDA label for Egrifta WR, revised March 2025 and Drugs@FDA record for BLA 022505.

Research material sold under the same name is a separate category from the approved drug. Curo's research catalog, which lists Tesamorelin 20mg, shows one such listing.

What is tesamorelin?

The FDA label calls tesamorelin "a human growth hormone-releasing factor (GRF) analog produced synthetically." FDA approved the first Egrifta product on November 10, 2010. The label's indication is narrow: "reduction of excess abdominal fat in HIV-infected adult patients with lipodystrophy." The page Is tesamorelin FDA approved? The FDA records follows the approval from 2010 to 2025.

How is tesamorelin built?

The label describes tesamorelin as "comprised of the 44 amino acid sequence of human GRF and a hexenoyl moiety, a C6 chain with a double bond at position 3, attached to the tyrosine residue at the N-terminal part of the molecule." The drug substance is an acetate salt. The label gives the molecular formula of tesamorelin acetate as C221H366N72O67S plus x C2H4O2, where x is about 7, and a molecular weight, as free base equivalent, of 5135.9 Da.

PubChem lists the same free-base formula under CID 16137828, with the names TH9507, GHRH(1-44) and Egrifta and the CAS number 218949-48-5. These values describe the reference compound, not a particular lot. Source: PubChem tesamorelin record, CID 16137828.

Is tesamorelin a peptide or a protein?

At 44 amino acids, tesamorelin is longer than the line that FDA's rule uses to define a protein. The rule at 21 CFR 600.3(h)(6) says: "A protein is any alpha amino acid polymer with a specific, defined sequence that is greater than 40 amino acids in size." FDA's Purple Book, its database of licensed biological products, lists tesamorelin under BLA 022505. Whether a 44-amino-acid chain is called a peptide or a protein depends on the definition in use. Sources: 21 CFR 600.3 definitions and FDA Purple Book record for tesamorelin.

How does tesamorelin act?

The label says that "In vitro, tesamorelin binds and stimulates human GRF receptors with similar potency as the endogenous GRF." It describes GRF, also called GHRH, as "a hypothalamic peptide that acts on the pituitary somatotroph cells to stimulate the synthesis and pulsatile release of endogenous growth hormone (GH)." Its pharmacodynamics section states that tesamorelin "stimulates growth hormone secretion, and subsequently increases IGF-1 and IGFBP-3 levels." Source: FDA label for Egrifta WR, revised March 2025.

Where has tesamorelin been studied?

The six reports below are human trials in defined groups. Each finding belongs to its group and its measure.

HIV and abdominal fat, 2007

The authors randomized 412 patients with HIV and abdominal fat accumulation to tesamorelin or placebo for 26 weeks. They reported that visceral adipose tissue, measured by computed tomography, fell 15.2% in the tesamorelin group and rose 5.0% in the placebo group, and that IGF-I rose 81.0% with tesamorelin. Adverse events did not differ significantly between groups, but more patients in the tesamorelin group withdrew because of an adverse event. Source: 2007 NEJM trial, PMID 18057338.

Two phase 3 trials pooled, 2010

The pooled analysis combined two multicenter, placebo-controlled phase 3 trials in 806 antiretroviral-treated patients with HIV and excess abdominal fat. At week 26 the authors reported a significant fall in visceral adipose tissue with tesamorelin and no significant change in abdominal subcutaneous adipose tissue. They concluded that the visceral fat reduction held for up to 52 weeks in patients who continued. A 2008 report of the extension phase states that visceral adipose tissue reaccumulated after tesamorelin was stopped. Sources: 2010 pooled analysis, PMID 20554713 and 2008 extension report, PMID 18690162.

Liver fat in HIV, 2014

A double-blind, placebo-controlled trial at Massachusetts General Hospital enrolled 50 antiretroviral-treated adults with HIV and abdominal fat accumulation. Over 6 months the authors reported reductions in visceral fat and liver fat. Fasting glucose was higher in the tesamorelin group at 2 weeks, and the 6-month changes in fasting and 2-hour glucose were not significant. The authors called the study preliminary and said further studies were needed. Source: 2014 JAMA trial, PMID 25038357.

Fatty liver disease in HIV, 2019

A randomized, double-blind, multicenter trial enrolled 61 people with HIV and a hepatic fat fraction of 5% or more. Over 12 months the authors reported a larger fall in hepatic fat fraction with tesamorelin than with placebo (absolute difference -4.1%) and no difference in fasting glucose or glycated haemoglobin. They wrote that further studies were needed on liver histology. Source: 2019 Lancet HIV trial, PMID 31611038.

Older adults and mild cognitive impairment, 2012

A randomized, double-blind, placebo-controlled trial at the University of Washington enrolled 152 adults aged 55 to 87, 66 of them with mild cognitive impairment, for 20 weeks. The authors reported a favorable effect on cognition in both groups, and mild adverse events in 68% of the tesamorelin group and 36% of the placebo group. They called for longer trials. Source: 2012 Archives of Neurology trial, PMID 22869065.

Neurocognitive impairment in HIV, 2025

A phase 2, open-label trial randomized 73 virally suppressed adults with HIV and abdominal obesity to tesamorelin or standard care for 6 months. The authors reported a larger fall in waist circumference with tesamorelin and no significant between-group difference in neurocognitive performance (P = .673). They noted limited power and no placebo arm. Source: 2025 Journal of Infectious Diseases trial, PMID 39813152.

Open the tesamorelin source ledger.

What does the trial registry show?

ClinicalTrials.gov holds the maker's phase 3 record, NCT00123253 (sponsor Theratechnologies), and academic records such as NCT02196831 (Massachusetts General Hospital) and NCT00257712 (University of Washington). A registry record describes a study's design and status. The papers above carry the results.

Where do the other tesamorelin questions go?

The FDA record is on tesamorelin FDA approval records. Comparisons with two other growth hormone-releasing compounds are on tesamorelin vs sermorelin and tesamorelin vs ipamorelin. Research material is on tesamorelin research material and lot records.

Where are lot documents for tesamorelin research material?

For a report tied to a lot number, open Curo's lot certificates. For what each report covers, open Curo's testing methods.