Tesamorelin.
Tesamorelin is a synthetic 44-amino-acid analog of human growth hormone-releasing hormone (GHRH/GRF 1-44), stabilized by a trans-3-hexenoic acid group attached to its N-terminus.
Tesamorelin is a synthetic 44-amino-acid analog of human growth hormone-releasing hormone (GHRH/GRF 1-44), stabilized by a trans-3-hexenoic acid group attached to its N-terminus. Tesamorelin is fda-approved, and PepCue grades its published evidence A tier (87/100). Also known as Egrifta. This is a research reference, not medical or dosing advice.
What it is
Tesamorelin is a synthetic 44-amino-acid analog of human growth hormone-releasing hormone (GHRH/GRF 1-44), stabilized by a trans-3-hexenoic acid group attached to its N-terminus. It is one of the few research peptides in its class that holds full FDA approval, marketed as Egrifta (and the reformulated Egrifta SV / Egrifta WR) by Theratechnologies for a narrow, specific indication. Originally designated TH9507, it is a secretagogue rather than a hormone itself.
How it works
Tesamorelin binds the GHRH receptor on the anterior pituitary, stimulating the synthesis and pulsatile release of the body's own growth hormone (GH), which in turn raises hepatic and circulating insulin-like growth factor-1 (IGF-1). Because it works upstream by amplifying endogenous GH secretion, it largely preserves physiological feedback and pulsatility, unlike direct exogenous GH administration. The N-terminal hexenoyl modification confers resistance to degradation (including by dipeptidyl peptidase-IV) and extends its half-life relative to native GHRH. The downstream rise in GH/IGF-1 drives lipolysis, with a notable effect on visceral (intra-abdominal) adipose tissue.
Mechanism pathways
Stimulating the pituitary's GHRH receptor to release the body's own growth hormone.
Growth-hormone-releasing hormone is made in the arcuate nucleus of the hypothalamus and travels through the hypophyseal portal circulation to the anterior pituitary, where it binds a class B G-protein-coupled receptor on somatotroph cells. Receptor activation raises intracellular cyclic AMP, which triggers both the synthesis of growth hormone and its release in pulses. Downstream, growth hormone acts on the liver and peripheral tissues to raise insulin-like growth factor 1, and IGF-1 in turn feeds back to restrain further growth hormone output. Somatostatin, released from a separate hypothalamic population, provides the opposing brake. The appeal of targeting this receptor rather than administering growth hormone directly is that the feedback architecture stays intact. Because release remains pulsatile and IGF-1 can still shut the system down, the pituitary sets a ceiling on how much growth hormone appears. Direct growth hormone administration bypasses that ceiling entirely. This is the central argument for the whole class, and it is a genuine pharmacological difference rather than a marketing distinction. All compounds in this group are analogs of the biologically active fragment of GHRH, which is the first twenty-nine amino acids. Native GHRH is cleaved almost immediately by dipeptidyl peptidase-4 at the amino terminus, so every analog is essentially a different answer to that vulnerability. Some substitute amino acids near the cleavage site. Some add a chemical group at the amino terminus that the enzyme cannot process. Some attach a linker that lets the molecule bind covalently to circulating albumin, stretching duration from minutes to days and turning discrete pulses into a sustained elevation, which is a meaningfully different physiological signal from a short pulse. One member of this group is an approved medicine for a specific indication, which means the receptor mechanism has been demonstrated in humans and not merely in animals. That approval does not extend to the rest of the group. Most of the compounds here have never been approved for any use anywhere, are sold as research chemicals of unverified identity and purity, and have human data limited to short studies showing that growth hormone rises after administration. Demonstrating that a hormone level moves is not the same as demonstrating that anything clinically meaningful follows from it, and for most of this class that second step has not been taken.
The evidence
Human evidence is unusually strong for one specific population: HIV patients with lipodystrophy. Two pivotal phase 3 randomized, placebo-controlled trials and their pooled analysis (Falutz et al., JAIDS 2010 and J Clin Endocrinol Metab 2010) showed roughly a 15-18% reduction in visceral adipose tissue over 26 weeks, with regain after discontinuation, supporting the FDA approval. Stanley et al. (JAMA 2014; PMID 25038357) and a randomized NAFLD trial (Stanley et al., Lancet HIV 2019; PMID 31611038) further demonstrated reductions in liver fat and a lower rate of fibrosis progression in HIV-associated fatty liver disease. Crucially, nearly all rigorous human data come from HIV-positive cohorts; use for general anti-aging, body recomposition, or NAFLD in HIV-negative people is extrapolation and has not been established in large controlled trials. Subcutaneous fat and total weight are largely unaffected, and effects reverse when treatment stops.
The evidence, in brief
The most clinically validated compound in this group. A pivotal 412-patient randomized, placebo-controlled trial (Falutz, NEJM 2007) showed ~15% reduction in visceral fat in HIV-associated lipodystrophy, and it is FDA-approved as EGRIFTA for that indication. Caveats: benefits aren't sustained after stopping, and approval is narrow: not general anti-aging or body-composition use.
- Falutz J et al.: Metabolic effects of a growth-hormone-releasing factor in patients with HIVN Engl J Med, 2007 (PMID 18057338)
- Stanley TL et al.: Tesamorelin on visceral and liver fat in HIV (randomized trial)JAMA, 2014 (PMID 25038357)
Evidence maturity
An evidence-only reading: approval status, human vs preclinical data, mechanism and safety. Popularity never raises it. Research file #063
Approved or strong, consistent human evidence.
FDA-approved for a specific indication: the strongest lane.
Claim receipts
Popular claims about Tesamorelin, checked against the state of the evidence. The verdict describes evidence maturity, never an invented study result.
Approved (Egrifta) for HIV-associated lipodystrophy on the basis of visceral-fat reduction.
Broad anti-aging use is not an approved or proven indication.
Safety profile
The most consistent documented concerns are glucose-related: because it raises GH/IGF-1, tesamorelin can worsen insulin sensitivity and glucose tolerance, and IGF-1 levels are monitored in clinical practice. Common adverse effects in trials included injection-site reactions, arthralgia, myalgia, peripheral edema, and paresthesia; hypersensitivity reactions have occurred. It is contraindicated in pregnancy and in people with active malignancy, since elevated IGF-1 is a theoretical tumor-growth concern, and in those with disrupted hypothalamic-pituitary axis (e.g., pituitary tumor/surgery, head irradiation). The NIH LiverTox database assigns it a low likelihood of causing clinically apparent liver injury. Long-term safety beyond the trial windows, and safety in non-HIV populations, remains poorly characterized.
Compound notes
- Tesamorelin is a stabilized GHRH analog that stimulates the pituitary's GH/IGF-1 axis.
- It is FDA-approved (brand Egrifta) for one specific indication: reducing excess visceral abdominal fat in HIV-associated lipodystrophy.
- It has also been studied in research settings for outcomes such as liver fat and cognition, which are not approved uses.
- Approved for a narrow indication; broad anti-aging / general GH-boosting use is neither approved nor proven.
- Raises IGF-1; caution around active malignancy and other label contraindications, per the FDA label.
Regulatory status
FDA-approved (2010, as Egrifta; reformulated as Egrifta SV in 2019 and the F8 formulation Egrifta WR in 2023) solely to reduce excess visceral abdominal fat in HIV-infected adults with lipodystrophy. All other uses are off-label, and it is a prescription drug, not a dietary supplement.
Approved by the FDA for at least one indication.
By the numbers
- 01A stabilized synthetic analog of GHRH (GRF 1-44), originally called TH9507
- 02Works as a GH secretagogue, raising the body's own GH and IGF-1 rather than supplying GH directly
- 03FDA-approved only for HIV-associated lipodystrophy (excess visceral abdominal fat)
- 04Preferentially reduces visceral fat with little effect on subcutaneous fat; effects reverse on discontinuation
- 05Can elevate blood glucose and reduce insulin sensitivity; IGF-1 is monitored clinically
- 06Contraindicated in active cancer and pregnancy due to GH/IGF-1 biology
Tesamorelin: research formats
Choose the format you are researching to see route-specific notes.
FDA-approved (EGRIFTA); provided as 2 mg vial with supplied sterile water diluent.
Tesamorelin (Egrifta) is the only GHRH analog FDA-approved for a human indication (HIV-associated lipodystrophy). It is dispensed as a 2 mg lyophilized vial with a 2.1 mL prefilled syringe of sterile water. Reconstituted concentration is approximately 1 mg/mL.
The off-label use of tesamorelin in research contexts (general body-composition improvement) uses the same subcutaneous route but is not an approved indication.
Sources
Every factual claim above resolves to a real, published source.
- Effects of tesamorelin, a growth hormone-releasing factor, in HIV-infected patients with abdominal fat accumulation: a randomized placebo-controlled trial (phase 3)J Acquir Immune Defic Syndr, 2010, PMID 20101189 (Falutz J et al.)
- Effect of tesamorelin on visceral fat and liver fat in HIV-infected patients with abdominal fat accumulation: a randomized clinical trialJAMA, 2014, PMID 25038357 (Stanley TL et al.)
- Effects of tesamorelin on non-alcoholic fatty liver disease in HIV: a randomised, double-blind, multicentre trialLancet HIV, 2019, PMID 31611038 (Stanley TL et al.)
- Tesamorelin: LiverTox, Clinical and Research Information on Drug-Induced Liver InjuryNIH/NIDDK LiverTox, NCBI Bookshelf (NBK548730)
Cite this page
PepCue. “Tesamorelin: the evidence.” PepCue, reviewed June 1, 2026. https://www.pepcue.app/p/tesamorelin.
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