Short answer: tesamorelin is a 44-amino-acid synthetic analogue of human growth hormone-releasing hormone (GHRH), modified at the N-terminus with a trans-3-hexenoic acid group to resist DPP-4 cleavage. It is the only FDA-approved peptide for visceral fat reduction, marketed as Egrifta (tesamorelin acetate) for HIV-associated lipodystrophy. The Phase 3 evidence reported roughly 15% mean reduction in visceral adipose tissue over 26 weeks at the 2 mg/day dose vs placebo. Half-life is short (~26 minutes) but the pituitary GH pulse it triggers is sufficient for daily-injection efficacy. New-U catalogues research-grade tesamorelin on the HGH / Somatropin shelf - sealed vials, per-batch CoA, research use only.
Tesamorelin search volume has grown from ~90,500 monthly US queries in September 2025 to over 135,000 by February 2026 - roughly 49% growth in six months, the fastest acceleration in the GHRH-class space. The interest tracks two adjacent threads: clinicians prescribing the approved Egrifta product, and the research community studying the underlying 44-residue molecule as the cleanest endogenous-GH-pulse-stimulating peptide on the shelf. This guide explains the molecule, the Phase 3 evidence, how tesamorelin differs from CJC-1295 and sermorelin, and how research-grade tesamorelin sits on the New-U catalogue. For the broader GH-releasing class explainer see Research Peptides: Quality, Testing & Buying Guide.
Plain-English summary. Tesamorelin is an approved medicine in the United States as Egrifta when supplied through a licensed pharmacy under prescription. Research-grade tesamorelin, sold as a lyophilised reference peptide for laboratory use, is a separate non-medicine category. New-U sells only the research reagent - not the medicine - with no human-use claims, no dosing guidance and no therapeutic protocol. This page is general information, not legal or medical advice.
Tesamorelin is a 44-amino-acid synthetic peptide whose sequence matches that of endogenous human growth hormone-releasing hormone (hGHRH 1-44), with a single engineering change: a trans-3-hexenoic acid (HEA) group is attached to the N-terminal tyrosine via an amide bond. The HEA modification has one job - to block the dipeptidyl peptidase-4 (DPP-4) cleavage site that would otherwise degrade the peptide within minutes of administration. With HEA in place, tesamorelin’s half-life extends to roughly 26 minutes, which is enough to drive a pituitary GH pulse but short enough that the GH signal remains physiologically pulsatile rather than flat.
That “pulsatile not flat” property is the whole design point. Endogenous GH is released in pulses by the pituitary every ~3 hours; flat-line elevation of GH (the way recombinant somatropin behaves) is known to produce different downstream effects than amplified pulsatile release. Tesamorelin’s mechanism is to amplify the pituitary’s own pulses, not to bypass the pituitary.
The GHRH receptor sits on somatotrophs in the anterior pituitary. When activated, it triggers cyclic AMP signalling that drives GH synthesis and release. Tesamorelin binds and activates the GHRH receptor with affinity comparable to endogenous GHRH, but persists long enough to evoke a meaningful GH pulse rather than being degraded before binding.
The full mechanism is reviewed in the published Phase 3 papers indexed under PubMed: tesamorelin.
Tesamorelin’s FDA approval rests on two pivotal Phase 3 trials in adults with HIV-associated lipodystrophy, the first published in the New England Journal of Medicine (Falutz et al., 2007) and the second in the same journal in 2008. Combined endpoints at 26 weeks of 2 mg/day subcutaneous tesamorelin vs placebo:
| Endpoint | Tesamorelin 2 mg/day | Placebo |
|---|---|---|
| Visceral adipose tissue change | −15.2% | −5.0% |
| Triglycerides | −50 mg/dL | +9 mg/dL |
| Total cholesterol : HDL ratio | Significant improvement | No change |
| IGF-1 | Significant elevation | No change |
The visceral-fat number is the headline: ~15% reduction in deep-belly adipose tissue, the metabolically active depot most associated with cardiovascular and metabolic risk. That endpoint, combined with the lipid-profile improvement, is the basis for the Egrifta approval. The approval is narrow - HIV-associated lipodystrophy - not general weight loss; tesamorelin is not approved as a weight-loss medicine.
All three are GHRH-class analogues; the engineering choices differ.
| Compound | Sequence basis | Modification | Half-life | Status |
|---|---|---|---|---|
| Tesamorelin | Full GHRH 1-44 | trans-3-hexenoic acid (HEA) at N-terminus | ~26 min | FDA approved (Egrifta) |
| Sermorelin | GHRH 1-29 | None (native fragment) | ~10–20 min | Previously approved (Geref, discontinued 2008 for commercial, not safety, reasons) |
| CJC-1295 (no DAC) | GHRH 1-29 | Aib substitutions for DPP-4 resistance | ~30 min | No approval |
| CJC-1295 with DAC | GHRH 1-29 | Aib + maleimide-Lys DAC for albumin binding | ~days | No approval |
The mechanistic point: tesamorelin and sermorelin and CJC-1295-no-DAC all preserve pulsatile GH release because their half-lives are minutes. CJC-1295 with DAC extends half-life into days, which produces a flatter, more continuous GH elevation - pharmacologically distinct from natural pituitary rhythm. Tesamorelin is the only one of the four with a Phase 3 outcomes trial behind it.
For the matching paired-research stack with a GHRP (ghrelin mimetic), see our CJC-1295 / Ipamorelin guide.
On the New-U catalogue, tesamorelin is listed on the HGH / Somatropin shelf as a lyophilised reference peptide. Sealed glass vial, lyophilised under nitrogen, for laboratory use only.
Lyophilised tesamorelin is stable at −20°C for long-term storage. The HEA-modified N-terminus is not especially labile and the peptide tolerates brief room-temperature excursions during shipment. Allow vials to warm to room temperature before opening to avoid condensation in the vial. Reconstitute in bacteriostatic water for research handling; once reconstituted, store at 2–8°C and protect from light. Reconstituted GHRH analogues are best used within a research-relevant time window. Full reference: How to Store Peptides.
For a 44-amino-acid HEA-modified peptide:
Full walkthrough: How to Read a Certificate of Analysis.
Walk away from any tesamorelin listing that:
What is tesamorelin?
A 44-amino-acid synthetic GHRH analogue with a trans-3-hexenoic acid modification at the N-terminus. FDA-approved as Egrifta (tesamorelin acetate) for HIV-associated lipodystrophy.
Is tesamorelin FDA-approved?
Yes. It is the only FDA-approved peptide indicated specifically for visceral fat reduction - though the approval is narrow (HIV-associated lipodystrophy), not general weight loss.
How is tesamorelin different from CJC-1295?
Both are GHRH-class analogues. Tesamorelin uses the full 44-residue backbone with HEA at the N-terminus (short half-life, preserves pulsatile GH). CJC-1295 uses the 29-residue fragment with optional DAC for albumin binding (long half-life with DAC, flatter GH profile).
What did the NIH study of tesamorelin show?
The pivotal Phase 3 trial (Falutz et al., NEJM 2007) reported a ~15% reduction in visceral adipose tissue over 26 weeks of 2 mg/day tesamorelin, with significant lipid-profile improvement vs placebo.
Is tesamorelin a research compound on this site?
Yes. New-U catalogues tesamorelin as a lyophilised reference peptide with a per-batch Certificate of Analysis. Sold research use only, not for human consumption.
External links are provided for research reference only; New-U is not affiliated with the cited organisations and links carry no endorsement either way. Egrifta is a trade name of Theratechnologies / EMD Serono; New-U sells research-grade reference peptide only, not the licensed medicine.
New-U Research Compounds catalogues tesamorelin as lyophilised reference peptide - sealed 10-vial packs, independently verified by Janoshik and Freedom Diagnostics for >99% HPLC purity, with a per-batch Certificate of Analysis. Tracked worldwide delivery. Research use only - not for human consumption.
View Tesamorelin