Tesamorelin
A stabilized growth hormone-releasing peptide approved to target visceral organ fat without shutting down natural hormone production.
The Hypothalamic–Pituitary–Liver Axis
Tesamorelin is a stabilized GHRH analogue that mimics the brain's natural trigger for growth hormone, targeting visceral abdominal fat while preserving natural hormonal feedback loops.
Pituitary GHRH
Binds pituitary somatotrophs, activating cAMP signaling.
Pulsatile GH
Stimulates natural pulses rather than constant supraphysiological flooding.
Liver IGF-1
GH reaches liver, prompting physiologic IGF-1 synthesis (+81%).
Visceral Lipolysis
Selectively triggers fat breakdown in deep abdominal organ deposits (-15.2%).
What is Tesamorelin?
Tesamorelin is a synthetic peptide that mimics human Growth Hormone-Releasing Hormone (GHRH). It consists of the first 44 amino acids of natural GHRH bonded to a trans-3-hexenoic acid group, which stabilizes the peptide and extends its activity in the body.
Why are people interested in it?
Interest in tesamorelin centers on its unique ability to reduce deep visceral abdominal fat (the dangerous fat packed around internal organs) without broadly shutting down the body's natural hormone production or spiking blood sugar the way synthetic growth hormone injections can.
Primary Research Categories
- GHRH analogues
- Approved drug substances
How does it work in the body?
Tesamorelin acts on the pituitary gland to encourage your body to manufacture and release its own natural growth hormone in normal, healthy pulses.
Endocrine Pathway
The GHRH – Pituitary – IGF-1 Axis
Instead of injecting direct growth hormone, GHRH analogues prompt the body’s own pituitary gland to manufacture and release growth hormone in natural, pulsatile bursts.
GHRH Analogue
Tesamorelin enters circulation and binds GHRH receptors on anterior pituitary somatotrophs.
Pulsatile GH
Stimulates natural, episodic pulses of endogenous human growth hormone (GH).
Hepatic IGF-1
Circulating GH stimulates the liver to synthesize and release Insulin-Like Growth Factor 1.
Lipolysis & Repair
Selectively triggers breakdown of abdominal visceral adipose tissue while maintaining lean mass.
1. Hypothalamus to Pituitary
Tesamorelin binds specifically to GHRH receptors on pituitary somatotroph cells.
2. Pulsatile Growth Hormone Release
Stimulates natural episodic spikes of growth hormone rather than a constant, unnatural flood.
3. Liver Production of IGF-1
Growth hormone reaches the liver, prompting the release of Insulin-Like Growth Factor 1 (IGF-1).
4. Visceral Fat Lipolysis
Elevated GH and IGF-1 selectively activate lipid breakdown in dense abdominal visceral fat deposits.
Key Distinction: Because tesamorelin preserves natural negative feedback loops (somatostatin regulation), it reduces the risk of excessive growth hormone levels seen with direct GH injections.
What has actually been demonstrated in humans?
Tesamorelin is an FDA-approved prescription drug (brand name EGRIFTA / EGRIFTA SV). It underwent extensive Phase 3 multicenter human trials demonstrating significant, measurable reductions in visceral adipose tissue in adult patients.
NEJM Phase 3 Clinical Trial (Falutz et al., 2007)
Duration: 26 weeks · Population: 412 patients with excess abdominal fat accumulationPublished Finding: Visceral abdominal fat decreased by an average of 15.2% in the tesamorelin group compared to an increase of 2.1% with placebo. IGF-1 increased by 81%.
Pharmaceutical Reality vs. Unregulated Research Chemicals
Tesamorelin is FDA-approved exclusively for reducing excess abdominal visceral fat in HIV-infected patients with lipodystrophy. The FDA label explicitly states that tesamorelin is not indicated for general weight loss or cosmetic body contouring in the general public. IGF-1 levels must be monitored clinically because elevated IGF-1 carries theoretical proliferative risks.
What is still uncertain or unknown?
No controlled clinical trials support its safety or effectiveness for general cosmetic fat loss or athletic enhancement in healthy individuals without HIV lipodystrophy. Long-term safety of sustained IGF-1 elevation in non-deficient populations remains unstudied.
Clinical Perspectives & Expert Discussions
Explore all perspectivesWhat identifiable clinicians, researchers, and professional bodies have publicly discussed regarding Tesamorelin.
Dr. Edwin Lee, M.D., F.A.C.E.
Board-certified in Internal Medicine and Endocrinology, Diabetes and Metabolism; Fellow of the American College of Endocrinology; founder of the Clinical Peptide Society.
Dr. Lee emphasizes that any clinical exploration of growth hormone secretagogues must be accompanied by comprehensive baseline and ongoing laboratory evaluation, including serum IGF-1, fasting insulin, HbA1c, and cancer screening. He cautions that secretagogues are biologically active molecules that influence cellular proliferation and glucose counter-regulation.
Dosing Reference
Open Tesamorelin Dosing ReferenceAn FDA-approved growth hormone-releasing factor analogue specifically indicated for HIV-associated lipodystrophy. Other cosmetic, bodybuilding, or anti-aging uses discussed online are unapproved.
Therapept separates official product labels, published clinical study interventions, animal research, clinical references, and community-reported ranges — never blended into one number.
Research at a Glance
Open the full evidence file (3 records)3 records in this file
- CLINICAL TRIAL1
- REGULATORY2
Publication span: 2007–2026
What Has Actually Been Studied
- WADA Prohibited List — S2.2.4 GHRH analogues (WADA Prohibited List, 2026) — Anti-doping listing.
- Drugs@FDA — EGRIFTA (BLA 022505) (Drugs@FDA, 2010) — Approved-drug labelling.
- Metabolic effects of a growth hormone-releasing factor in patients with HIV (New England Journal of Medicine, 2007) — Randomised, double-blind, placebo-controlled trial.
What is Still Unknown
What we know
- FDA-approved as EGRIFTA (BLA 022505, 2010). Falutz et al. 2007 (NEJM) is a primary interventional paper in the HIV-lipodystrophy programme.
- It is the only GHRH analogue in this library with a currently marketed United States approval.
- Also named on the WADA GHRH-analogue list — approval and sporting prohibition are different questions.
Editorial reading of the records below, labelled as Therapept analysis. How records are built
What remains uncertain
- Orthopaedic or “performance” endpoints: 2026 sports-medicine reviews report no supporting evidence in those settings.
Preparation and Handling
Lyophilized peptides ship as freeze-dried powders; whatever happens next involves diluents, concentrations and storage conditions that are compound- and product-specific.
United States Regulatory Status
FDA-approved drug substance
Application: BLA 022505 (EGRIFTA)
Approved Indication: Marketed in the United States as EGRIFTA, an approved prescription product administered subcutaneously.
- EGRIFTA, BLA 022505, approved 10 November 2010. Active prescription product.
- Not listed on FDA's Category 2 or withdrawn-nomination compounding tables.
WADA Anti-Doping Status
Named at S2.2.4 among GHRH analogues. Prohibited at all times; non-Specified.
Technical Chemical SpecificationsClick to view CAS, sequence, and molecular formulas
- Molecular weight
- 5136 g/mol
- Sequence length
- 31 chars
- CAS number
- 218949-48-5
- PubChem CID
- 16137828
- Compound class
- Stabilised GHRH analogue — human GHRH(1-44) amide, N-terminally acylated
- Sequence
- trans-3-hexenoyl-GHRH(1-44)-NH2
- Molecular formula
- C221H366N72O67S
- Molecular weight
- 5136 g/mol
- CAS number
- 218949-48-5
- PubChem CID
- 16137828
Sources
- PubChem CID 16137828
- Drugs@FDA — approved drug products
- WADA 2026 Prohibited ListEffective 1 January 2026.
Last reviewed 3 September 2026 · Compiled by Therapept Editorial · How these records are built