Research and laboratory use only. Not for human consumption.
Tesamorelin
Tesamorelin is a synthetic analogue of human growth hormone-releasing hormone designed to stimulate endogenous growth hormone secretion while retaining the physiological GH/IGF-1 axis. Unlike direct growth-hormone administration, tesamorelin acts upstream at the pituitary through the growth hormone-releasing hormone receptor.
What is Tesamorelin?
Tesamorelin is a synthetic analogue of human growth hormone-releasing hormone , also historically called growth hormone-releasing factor.
Human GHRH is produced primarily in the hypothalamus and stimulates somatotroph cells within the anterior pituitary to release growth hormone.
Tesamorelin was engineered to preserve the biological activity of endogenous GHRH while improving resistance to rapid enzymatic degradation.
Its principal pharmacological action is activation of the GHRH receptor on pituitary somatotroph cells.
This increases endogenous pulsatile growth hormone secretion and subsequently increases production of insulin-like growth factor 1, or IGF-1.
The molecule has been investigated most extensively in people with HIV-associated lipodystrophy and excess visceral abdominal adipose tissue.
Tesamorelin ultimately became the first FDA-approved pharmacological treatment specifically indicated to reduce excess abdominal fat in adults with HIV-associated lipodystrophy.
Why is it called Tesamorelin?
Tesamorelin is the international generic name assigned to the stabilized synthetic GHRH analogue.
The suffix “-morelin” appears in several compounds that act on growth-hormone secretory pathways, although these compounds can work through different receptors.
Tesamorelin should therefore be distinguished from growth-hormone secretagogues such as Ipamorelin, GHRP-6 and Hexarelin .
Those peptides primarily interact with the ghrelin receptor, whereas Tesamorelin acts through the GHRH receptor.
It should also be distinguished from recombinant growth hormone itself because Tesamorelin stimulates endogenous pituitary GH secretion rather than supplying exogenous GH directly.
A stabilized GHRH peptide analogue
Tesamorelin is based on the full 44-residue human GHRH sequence but contains an N-terminal modification designed to increase resistance to enzymatic cleavage while preserving receptor activity.
How does the GHRH pathway work?
Endogenous GHRH is released by hypothalamic neurons and travels through the hypophyseal portal circulation to the anterior pituitary.
There it activates GHRH receptors on somatotroph cells.
Receptor activation stimulates synthesis and release of endogenous growth hormone.
Growth hormone subsequently acts on several tissues, including the liver, where it stimulates synthesis of IGF-1.
This endocrine axis is regulated through feedback loops involving somatostatin, IGF-1 and other metabolic signals.
Tesamorelin therefore enhances an existing physiological signalling pathway rather than replacing growth hormone directly.
How can Tesamorelin alter body composition?
Tesamorelin's effects arise principally through increased endogenous growth-hormone signalling and subsequent changes in lipid metabolism.
Pituitary Signalling
Tesamorelin activates GHRH receptors on pituitary somatotrophs.
Endogenous GH
Growth-hormone secretion increases while remaining under endogenous endocrine regulatory mechanisms.
IGF-1
Increased GH signalling leads to increased circulating IGF-1 concentrations.
Lipid Metabolism
Growth-hormone signalling promotes lipolytic pathways and can preferentially influence visceral adipose tissue.
Tesamorelin's established clinical effect is reduction of excess abdominal visceral adipose tissue in adults with HIV-associated lipodystrophy.
Visceral fat is not the same as body weight
Visceral adipose tissue is fat stored within the abdominal cavity around internal organs.
It differs biologically from subcutaneous fat, which is located beneath the skin.
HIV-associated lipodystrophy can produce disproportionate accumulation of visceral abdominal fat even when total body weight does not change dramatically.
Clinical studies of Tesamorelin demonstrated preferential reductions in visceral adipose tissue rather than large reductions in total body mass.
This distinction explains why the FDA label explicitly states that Tesamorelin is not indicated for weight-loss management .
The approved product is described as having a generally weight-neutral effect.
What has Tesamorelin been investigated for?
Research has focused primarily on abnormal body composition and metabolic complications in people living with HIV.
Visceral Adiposity
Large clinical programmes established reduction of excess abdominal visceral adipose tissue.
Liver Fat
Controlled studies have investigated hepatic fat reduction in people with HIV and fatty liver disease.
Glucose Metabolism
Because GH can influence insulin sensitivity, glucose-related outcomes are closely monitored in clinical research.
Cardiometabolic Risk
Researchers continue to investigate how changes in visceral fat relate to broader cardiometabolic outcomes.
Evidence in HIV-associated lipodystrophy
Tesamorelin was evaluated in large randomized placebo-controlled trials before receiving regulatory approval.
HIV-associated abdominal fat
Randomized controlled studies evaluated Tesamorelin in adults with HIV and excess abdominal visceral adipose tissue.
Two pivotal Phase III programmes demonstrated clinically meaningful reductions in visceral adipose tissue compared with placebo.
Tesamorelin produced considerably greater changes in visceral abdominal fat than in subcutaneous adipose tissue.
Participants who continued treatment into extension phases generally maintained reductions in visceral adiposity.
In contrast, participants switched from Tesamorelin to placebo showed evidence of reaccumulation of visceral fat.
This demonstrated that the effect is pharmacologically maintained rather than representing a permanent remodeling of adipose tissue after treatment ends.
A 2026 meta-analysis of randomized controlled trials continues to support Tesamorelin's ability to reduce visceral adipose tissue in adults with HIV-associated lipodystrophy.
Tesamorelin and hepatic fat
Liver-fat reduction is scientifically promising but remains separate from Tesamorelin's FDA-approved indication.
Hepatic fat fraction
−37%Relative reduction from baseline in hepatic fat fraction reported after 12 months compared with placebo.
The absolute treatment effect was approximately −4.1 percentage points.
A randomized, double-blind multicentre trial investigated Tesamorelin in people living with HIV who also had non-alcoholic fatty liver disease.
Sixty-one participants were enrolled and hepatic fat was quantified by proton magnetic-resonance spectroscopy.
After 12 months, Tesamorelin produced an absolute treatment effect of approximately −4.1% in hepatic fat fraction compared with placebo.
This corresponded to an approximately 37% relative reduction from baseline. :contentReference[oaicite:1]{index=1}
Thirty-five percent of participants receiving Tesamorelin had hepatic fat fractions below 5% at 12 months compared with 4% receiving placebo. :contentReference[oaicite:2]{index=2}
These results support continued research into liver-fat and metabolic effects, but Tesamorelin is not currently FDA-approved specifically as a treatment for fatty liver disease.
Tesamorelin is an FDA-approved medicine
The approval is highly specific. Tesamorelin should not be presented as a general-purpose weight-loss, bodybuilding, anti-ageing or growth-hormone-enhancement medicine.
EGRIFTA — Tesamorelin
Tesamorelin is FDA approved for the reduction of excess abdominal fat in HIV-infected adult patients with lipodystrophy .
Current FDA labeling for EGRIFTA WR specifically states that long-term cardiovascular safety has not been established. :contentReference[oaicite:3]{index=3}
The label also states that Tesamorelin is not indicated for weight-loss management because the approved therapy is considered weight neutral overall. :contentReference[oaicite:4]{index=4}
EGRIFTA SV and EGRIFTA WR are different pharmaceutical formulations and the FDA prescribing information states that the formulations are not interchangeable on a simple strength-for-strength basis. :contentReference[oaicite:5]{index=5}
Regulatory approval of pharmaceutical Tesamorelin does not establish equivalence between approved EGRIFTA formulations and independently manufactured research material.
What safety issues are clinically important?
Tesamorelin has substantially more human safety data than most research peptides because it has undergone large controlled trials and regulatory review.
Increased IGF-1
Tesamorelin increases endogenous GH and IGF-1 signalling, making elevated IGF-1 a clinically monitored pharmacodynamic effect.
Glucose Effects
Growth-hormone signalling can influence glucose metabolism, and FDA labeling warns about glucose intolerance or diabetes.
Local Reactions
Injection-site erythema, itching, pain and related local reactions have been reported clinically.
Fluid Retention
GH-related fluid-retention effects can include oedema, arthralgia and musculoskeletal symptoms.
Current FDA prescribing information contraindicates EGRIFTA in patients with active malignancy and includes precautions relating to neoplasms because Tesamorelin increases growth-hormone and IGF-1 signalling. The approved label also includes precautions concerning glucose intolerance, hypersensitivity and fluid retention. :contentReference[oaicite:6]{index=6}
How strong is the evidence?
Tesamorelin has a well-established mechanism, multiple randomized human trials and an FDA-approved indication. Evidence is strongest for visceral-fat reduction in HIV-associated lipodystrophy.
Molecular Pharmacology
GHRH-receptor agonism and activation of the endogenous GH/IGF-1 axis are well characterized.
Visceral Fat Evidence
Multiple randomized controlled trials demonstrate reductions in visceral abdominal adipose tissue.
Regulatory Evidence
Tesamorelin has undergone formal regulatory review and has an approved indication in adults with HIV-associated lipodystrophy.
Other Applications
Liver-fat and broader metabolic research is promising but does not establish approved general weight-loss or metabolic indications.
What should not be assumed?
Factors affecting Tesamorelin stability
Tesamorelin is a relatively large peptide analogue. Laboratory stability depends on the exact formulation, salt form, concentration, temperature, pH and manufacturing specification. Approved EGRIFTA formulations have their own specific validated storage requirements and should not be used to infer handling conditions for unrelated research material.
Temperature
Elevated temperature can accelerate peptide degradation and reduce molecular integrity.
Moisture
Humidity can influence stability of dry and lyophilized peptide preparations.
Solution Environment
Buffer, pH, concentration and solvent conditions can affect peptide integrity after preparation in solution.
Material Specification
Identity, purity, aggregation state and chemical form should be defined analytically for the research material.
FDA-approved GHRH analogue with a specific HIV-associated lipodystrophy indication
Tesamorelin is a stabilized synthetic analogue of human growth hormone-releasing hormone that activates the pituitary GHRH receptor and increases endogenous growth hormone and IGF-1 signalling.
FDA-approved Tesamorelin is indicated for reduction of excess abdominal fat in adults living with HIV who have lipodystrophy. :contentReference[oaicite:7]{index=7}
It is not FDA approved as a general-purpose weight-loss medicine , and current prescribing information specifically describes the treatment as weight neutral. :contentReference[oaicite:8]{index=8}
Randomized research has also demonstrated reductions in hepatic fat among selected people living with HIV and fatty liver disease, but this remains distinct from the approved indication. :contentReference[oaicite:9]{index=9}
ASA Research Labs provides this information for scientific and educational purposes only. Discussion of approved pharmaceutical Tesamorelin does not establish equivalence between EGRIFTA and independently manufactured research material and does not constitute prescribing, administration or dosing guidance.
Selected scientific references
Selected literature and regulatory sources covering GHRH pharmacology, visceral adipose tissue, HIV-associated lipodystrophy, hepatic-fat research and current Tesamorelin regulatory status.
Scientific and regulatory information
This profile is provided for scientific and educational purposes. Tesamorelin is the active peptide in FDA-approved prescription medicines for a specific indication involving excess abdominal fat in adults with HIV-associated lipodystrophy. It is not presented here as a general weight-loss, bodybuilding, anti-ageing or performance-enhancing medicine. Research involving hepatic fat, metabolism or other potential applications does not establish additional approved indications. Regulatory approval of EGRIFTA does not establish the identity, purity, sterility, bioavailability or clinical equivalence of independently manufactured Tesamorelin research material. This page does not provide instructions for administration, dosing or unsupervised human use.