Section 01
What it's used for
FDA-approved for HIV belly fat
Tesamorelin (Egrifta) is FDA-approved to reduce excess belly fat in people with HIV. In the LIPO-010 and LIPO-012 Phase 3 trials, it reduced fat around the internal organs by 15-20% on CT scan and improved patients' reported body image.
▸Clinical wording
Tesamorelin (Egrifta) is FDA-approved for reducing excess abdominal fat in HIV-infected patients. Clinical trials (Phase 3: LIPO-010, LIPO-012) demonstrated 15-20% reduction in visceral adipose tissue (VAT) measured by CT scan, improved trunk fat ratio, and improved patient-reported body image outcomes.
One HIV-specific liver fat trial
In a Phase 2 trial of 61 people with HIV-related fatty liver, tesamorelin reduced liver fat measured by MR spectroscopy. The authors said liver-scarring effects need more study; they did not confirm improvement. One small HIV-only trial.
▸Clinical wording
A Phase 2 randomized, double-blind trial evaluated tesamorelin in HIV-associated non-alcoholic fatty liver disease (n=61), using proton MR spectroscopy rather than MRI-PDFF to measure hepatic fat, and found a reduction in hepatic fat fraction; the trial authors concluded that effects on liver fibrosis require further study rather than reporting confirmed fibrosis improvement. This is a single Phase 2 human trial restricted to an HIV population, not the Phase 2/3 program in general NASH implied by describing it that way.
Cognition trials found no clear effect
In a 2012 trial (n=152, University of Washington), this hormone showed only a non-significant trend toward better verbal memory (P=.08). A 2026 trial (n=22, Galveston, Texas) found no significant change on standard cognitive tests.
▸Clinical wording
Human trials of growth hormone-releasing hormone (of which tesamorelin is an analog) on cognition were conducted at the University of Washington School of Medicine (n=152, 2012) and the University of Texas Medical Branch, Galveston (n=22, 2026), not at Harvard or Massachusetts General Hospital. The 2012 trial found only a non-significant trend toward improved verbal memory (P=.08), and the 2026 trial found no significant changes on standard cognitive or connectivity measures, with only exploratory machine-learning-detected regional differences. These findings do not support a confirmed improvement in verbal memory, executive function, or prefrontal cognitive network connectivity.
Not studied outside HIV patients
Tesamorelin is approved only for reducing fat around the internal organs in HIV patients. No published trial was found testing this in people without HIV, such as those with metabolic syndrome or age-related weight gain around the organs.
▸Clinical wording
Tesamorelin is approved for visceral fat reduction specifically in HIV-associated lipodystrophy, but no published trial was found testing it for visceral fat reduction in non-HIV populations such as metabolic syndrome or age-related visceral adiposity. This direction appears in vendor and community material, but no published human study for non-HIV populations was found.
Early interest in nerve health
Researchers are exploring whether tesamorelin could support nerve function outside the brain and spine, via IGF-1, a hormone tied to growth. This is an early lead for diabetic and HIV-related nerve damage, not an established use.
▸Clinical wording
Studies suggest tesamorelin may improve peripheral nerve function through IGF-1-mediated neurotrophic effects, relevant to diabetic neuropathy and HIV-associated neuropathy.
Section 02
Mechanism of Action
Pressing the pituitary's growth-hormone button
- It binds the receptor for growth-hormone-releasing hormone on hormone-producing pituitary cells.
- Its effect there is as strong as the body's own releasing hormone.
- The receptor triggers an internal messenger cascade (cAMP-PKA) that makes and releases growth hormone.
▸Clinical wording
GHRH Receptor Agonism
Tesamorelin binds to and activates the GHRH receptor (GHRH-R) on pituitary somatotroph cells with full agonist activity equivalent to native GHRH. Receptor activation stimulates the Gαs-adenylyl cyclase-cAMP-PKA cascade, driving GH gene transcription and GH granule exocytosis.
Louder natural pulses, same rhythm
- It makes the body's own growth-hormone pulses larger while keeping their natural pulse pattern.
- The brain's braking signal (somatostatin) keeps regulating release as usual.
- The resulting IGF-1 levels stay inside the normal range for young adults.
▸Clinical wording
Physiological GH Pulse Amplification
Like sermorelin, tesamorelin amplifies endogenous GH pulses while preserving pulsatile secretion patterns and somatostatin feedback regulation. The resulting GH increase is physiological in character, producing IGF-1 elevations within the normal range for young adults.
Why deep belly fat shrinks
- Growth hormone switches on a fat-splitting enzyme inside fat cells.
- Deep abdominal fat carries more growth-hormone receptors than fat under the skin, so it is mobilised first.
- Clinical trials have shown visceral fat falling by 15-20%.
▸Clinical wording
Visceral Fat Reduction
The primary therapeutic effect — selective visceral fat reduction — is mediated through GH-stimulated lipolysis. GH activates hormone-sensitive lipase in adipocytes via JAK2-mediated signaling, preferentially mobilizing visceral adipose tissue (which has higher GH receptor density than subcutaneous fat). Visceral fat reductions of 15-20% have been demonstrated in clinical trials.
Less fat stored in the liver
- Growth hormone makes liver cells burn more fatty acids.
- It also lowers how much new fat the liver builds from scratch.
- The effect runs through growth-hormone receptors on liver cells and their fat-burning machinery (CPT-1).
▸Clinical wording
Hepatic Fat Reduction
Tesamorelin reduces hepatic steatosis (liver fat) through GH-mediated enhancement of hepatic fatty acid oxidation and reduced de novo lipogenesis. This effect is mediated through GH receptor activation in hepatocytes, stimulating CPT-1 expression and mitochondrial beta-oxidation.
The body's own brake stays intact
- Unlike injected growth hormone, this peptide leaves the brain-pituitary feedback loop working.
- The braking hormone somatostatin still decides how much growth hormone is released.
- That feedback keeps hormone levels from climbing above the body's normal range.
▸Clinical wording
Preserved Somatostatin Feedback
Unlike exogenous GH administration, tesamorelin preserves normal hypothalamic-pituitary feedback mechanisms. Somatostatin continues to regulate GH secretion, preventing supraphysiological GH levels and providing an inherent safety margin.
Section 03
Biological Pathways
- GHRH-R/cAMP/PKA/CREB SignalingTesamorelin is a full GHRH receptor agonist, activating the Gαs-adenylyl cyclase-cAMP-PKA cascade; PKA phosphorylates CREB to drive GH gene transcription and triggers GH granule exocytosis via calcium channels.
- Physiological Pulse AmplificationUnlike exogenous GH, tesamorelin amplifies endogenous GH pulses while preserving pulsatile secretion and somatostatin feedback, keeping IGF-1 elevations within the normal range for young adults.
- GH/JAK2/HSL Visceral LipolysisGH activates JAK2, phosphorylating hormone-sensitive lipase and perilipin in adipocytes, preferentially mobilizing visceral fat; trials have shown visceral fat reductions of 15-20%.
- GH/CPT-1 Hepatic Fat OxidationGH signaling upregulates CPT-1, the rate-limiting enzyme for mitochondrial fatty acid import, while reducing de novo lipogenesis, lowering hepatic triglyceride content and easing fatty liver disease.
Section 04
Dosage Information
trans-3-hexenoic acid-Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-Gln-Gln-Gly-Glu-Ser-Asn-Gln-Glu-Arg-Gly-Ala-Arg-Ala-Arg-Leu-NH2| Route / system | Context | Range studied | Limitation |
|---|---|---|---|
| Subcutaneous — approved indication | FDA label, lipodystrophy in HIV | 2 mg a day into the belly for the original EGRIFTA; the newer EGRIFTA SV is 1.4 mg and EGRIFTA WR 1.28 mg, not interchangeable. | The label covers only excess belly fat in HIV lipodystrophy; it says outright that the drug is not for weight loss and that long-term heart safety is unknown. |
| Subcutaneous — phase 3 trials | Two 26-week trials in HIV, extra belly fat | 2 mg a day for 26 weeks: visceral fat fell about 15% against a 5% rise on placebo, and those moved to placebo regained 16–22%. | The effect lasts only as long as the injections. What was measured was visceral fat on a scan, not weight or health outcomes; nothing past 52 weeks was tested. |
| Subcutaneous — liver-fat trial | 12-month randomised trial, HIV with fatty liver | 2 mg a day for 12 months in 61 people — the label dose, but a different question: fat in the liver and its scarring, not belly fat. | Another HIV group on antiretrovirals. All controlled results for tesamorelin come from that one population, so nothing carries over to fatty liver in others. |
| Subcutaneous — trial outside HIV | 20-week memory trial, the largest dosing outside HIV | 1 mg a day before bed for 20 weeks in 152 adults aged 55–87: growth factor IGF-1 rose 117%, body fat fell 7.4%. | Half the label dose, in a trial built to measure memory, not fat. The body-fat figure is a side reading over five months, with no scan of where that fat sat. |
| Subcutaneous — self-administration | Off-label practice for fat loss, outside any trial | 1–2 mg a day, sometimes five days on and two days off — the HIV label number carried over to people it was never tested in. | Circulating practice, not a finding: no randomised trial has tested belly fat in adults without HIV. The regain when phase 3 stopped the drug applies here too. |
Results
Syringe Fill Level (100u syringe)
Set positive values for: Recommended dose per kg.
Research Use Only. This information is for educational and research purposes only. Not intended for medical advice or self-medication.
Section 05
Protocols
No protocols featuring this peptide yet. Browse All Protocols
Section 06
Stability & Storage
Lyophilised powder
Supplied commercially as a lyophilised powder (1 mg or 2 mg vials) with a diluent, stored at controlled room temperature (20–25 °C) for up to 2 years. It is reconstituted with the provided sterile water, swirled gently until dissolved rather than shaken.
After reconstitution
The reconstituted solution is used immediately after preparation and is not intended for storage. The methionine at position 27 is susceptible to oxidation, so exposure to strong oxidizing conditions is avoided.
Section 07
Side Effects & Precautions
Tesamorelin's most commonly reported effects are injection-site reactions, in up to 25% of patients, along with GH-related effects on joints, fluid balance, muscles, and nerves; a smaller group of effects involves blood sugar and allergic reactions.
Injection site reactions (most common)
Redness (erythema), itching, pain, swelling, and irritation at injection sites are the most frequently reported effects, in up to 25% of patients. These reactions are generally mild to moderate and tend to decrease with continued use.
Joint, fluid, and muscle effects
- Joint pain (arthralgia) occurs in about 13% of patients, attributed to GH-related effects on connective tissue; usually mild and manageable.
- Mild fluid retention in arms, legs, or feet (peripheral edema), in 6-8% of patients — a GH class effect easing within the first weeks of treatment.
- Muscle aches (myalgia) are reported in about 5% of patients, usually mild and temporary.
Nerve-related effects
- Numbness or tingling (paresthesia), in 3-4% of patients, typically in the arms or legs, related to GH-driven fluid effects on peripheral nerves.
- Carpal tunnel syndrome, in 2-3% of patients, a recognized complication of GH excess; symptoms ease with a lower dose or with stopping treatment.
Effect on blood sugar
GH-related insulin resistance may modestly raise fasting blood sugar (glucose). This effect concerns people who already have pre-diabetes or diabetes.
Allergic reactions and contraindication
Rare allergic reactions, including hives (urticaria) and itching, have been reported. Tesamorelin is contraindicated in people with known hypersensitivity to GHRH or to mannitol, an inactive ingredient.
Section 08
Regulatory Status
Outside HIV-associated lipodystrophy and outside North America its status turns investigational, and WADA bans it outright regardless of the approved diagnosis.
FDA / United States
Approved for HIV lipodystrophy only
The FDA approved tesamorelin as Egrifta in 2010 for reducing excess abdominal fat in HIV-infected adults with lipodystrophy; a reformulation, Egrifta WR, was approved in 2025 for once-weekly reconstitution. It remains the only GHRH analog FDA has approved for any indication, and it is prescription-only.
EMA / European Union
Not approved
Theratechnologies withdrew its EU marketing-authorisation application for Egrifta in 2012 after the CHMP found the cardiovascular-safety and IGF-1 data insufficient for a positive benefit-risk balance; no EU-approved tesamorelin product exists today.
Health Canada
Approved for the same indication
Health Canada authorised tesamorelin as Egrifta for reduction of excess abdominal fat in HIV-associated lipodystrophy, making it the only other regulator alongside the FDA to approve the drug for therapeutic use.
WADA
Prohibited under category S2
Tesamorelin is a growth-hormone-releasing factor, banned for competing athletes at all times, in and out of competition; the approved HIV indication does not create an automatic exemption from testing.
Off-label use — for muscle growth, fat loss, or anti-aging outside the approved diagnosis — falls under none of these approvals and none of their oversight. Regulatory status differs between jurisdictions and changes over time; check the current documents of your own regulator before relying on any of this.
Section 09
Research Studies
- [1]Non-Clinical Pharmacology and Safety Evaluation of TH9507, a Human Growth Hormone-Releasing Factor AnalogueFerdinandi ES, Brazeau P, High K, et al. · Basic & Clinical Pharmacology & Toxicology · 2007
- [2]Metabolic Effects of a Growth Hormone-Releasing Factor in Patients with HIVFalutz J, Allas S, Blot K, et al. · New England Journal of Medicine · 2007
- [3]Long-term safety and effects of tesamorelin, a growth hormone-releasing factor analogue, in HIV patients with abdominal fat accumulationFalutz J, Allas S, Mamputu JC, et al. · AIDS · 2008
- [4]Effects of Tesamorelin, a Growth Hormone-Releasing Factor, in HIV-Infected Patients With Abdominal Fat Accumulation: A Randomized Placebo-Controlled Trial With a Safety ExtensionFalutz J, Potvin D, Mamputu JC, et al. · Journal of Acquired Immune Deficiency Syndromes · 2010
- [5]Reduction in Visceral Adiposity Is Associated With an Improved Metabolic Profile in HIV-Infected Patients Receiving TesamorelinStanley TL, Falutz J, Marsolais C, et al. · Clinical Infectious Diseases · 2012
- [6]Metabolic Effects of a Growth Hormone-Releasing Factor in Obese Subjects with Reduced Growth Hormone Secretion: A Randomized Controlled TrialMakimura H, Feldpausch MN, Rope AM, et al. · Journal of Clinical Endocrinology & Metabolism · 2012
- [7]Growth Hormone-Releasing Hormone Effects on Brain Gamma-Aminobutyric Acid Levels in Mild Cognitive Impairment and Healthy AgingFriedman SD, Baker LD, Borson S, et al. · JAMA Neurology · 2013
- [8]Effect of Tesamorelin on Visceral Fat and Liver Fat in HIV-Infected Patients With Abdominal Fat Accumulation: A Randomized Clinical TrialStanley TL, Feldpausch MN, Oh J, et al. · JAMA · 2014
- [9]Effects of tesamorelin on non-alcoholic fatty liver disease in HIV: a randomised, double-blind, multicentre trialStanley TL, Fourman LT, Feldpausch MN, et al. · The Lancet HIV · 2019
- [10]Effects of tesamorelin on hepatic transcriptomic signatures in HIV-associated NAFLDFourman LT, Billingsley JM, Agyapong G, et al. · JCI Insight · 2020
Section 10
Frequently Asked Questions
For its approved use, yes: two 26-week phase 3 trials (LIPO-010, LIPO-012) in HIV-associated lipodystrophy showed visceral fat falling about 15% while it rose 5% on placebo. No published controlled trial has tested it for visceral fat loss in people without HIV, so that use rests on the same mechanism rather than its own evidence.
Every controlled trial behind its approval enrolled people with HIV-associated lipodystrophy — the two pivotal 26-week trials and the later 12-month liver-fat study all drew from that same population. No published trial has tested tesamorelin for visceral fat reduction in adults without HIV, which is why the FDA label is restricted to that one condition and states outright it is not a weight-loss drug.
The pivotal trials only measured the endpoint at 26 weeks, where visceral fat had dropped about 15%. A separate 20-week trial in older adults reported a 7.4% drop in body fat as a secondary finding. No study has tracked when the change begins, so nothing shorter than these windows has been measured.
In the phase 3 program, patients who were switched from tesamorelin to placebo regained 16 to 22% of the visceral fat they had lost. The effect appears to depend on continued dosing rather than producing a lasting change, though nothing was tracked past 52 weeks.
Injection-site reactions are the most common, affecting up to 25% of patients, followed by joint pain (about 13%) and mild fluid retention (6 to 8%). Because it raises growth hormone and IGF-1, it can modestly raise blood glucose, and the label calls for monitoring in people who are pre-diabetic or diabetic.
It is FDA- and Health Canada–approved by prescription only, specifically for HIV-associated lipodystrophy, not for general weight loss. WADA prohibits tesamorelin at all times under category S2, growth hormone-releasing factors — a different, restricted class from the GLP-1/GIP weight-loss drugs, which are not on that list.
No published trial has tested combining tesamorelin with tirzepatide, retatrutide or other GLP-1/GIP therapies. They act through different hormone systems — growth hormone release versus incretin signaling — but there is no human safety or efficacy data for using them together.