Tesamorelin at a glance
Most synthetic GHRH analogues are cut down to the first 29 residues of growth-hormone-releasing hormone, the shortest stretch that still switches on the receptor. Tesamorelin keeps all 44 amino acids of the human hormone and adds a single modification, a trans-3-hexenoyl group on the tyrosine at the N-terminus. It came out of a Canadian programme with the development code TH9507; the US brand is Egrifta.
Unusually for this site, the molecule is the active substance of a licensed medicine with randomised phase 3 trials behind it. Research material with the same name is not that medicine.
- 44 amino acids, 5135.9 Da; acts on the GHRH receptor of the pituitary.
- Half-life of roughly 26–38 minutes; the trials dosed once a day.
- Phase 3: visceral fat about 15% lower after 26 weeks in adults with HIV.
- Approved in the US in 2010; no authorisation in the EU.
How Tesamorelin works
Tesamorelin binds the GHRH receptor on the somatotrophs of the anterior pituitary. Cyclic AMP rises, the cell makes more growth hormone (GH) and releases what it has in store. Native GHRH would be cut in two by dipeptidyl peptidase-4 within minutes; the hexenoyl group on the first residue protects the peptide from that enzyme.
Acting above the pituitary, instead of supplying GH itself, keeps the control loops working. Somatostatin still brakes and feedback from IGF-1 continues; trial data showed GH still arriving in pulses.
The clinical rationale was narrow. People living with HIV on long-term antiretroviral therapy can build up fat around the abdominal organs (visceral fat), and blunted GH secretion is part of that picture. GH breaks down fat and the visceral depot is sensitive to it. The idea was therefore to restore the body’s own secretion instead of replacing the hormone.
The evidence ladder for Tesamorelin
| Evidence level | Model or trial | Main finding |
|---|---|---|
| Human pharmacology | Hormone measurements in the clinical programme | GH and IGF-1 rise; pulsatile GH secretion is preserved |
| Randomised trial | Phase 3, double-blind, placebo-controlled, in adults with HIV and excess abdominal fat (New England Journal of Medicine, 2007) | Visceral fat on CT roughly 15% lower after 26 weeks against a slight rise on placebo; subcutaneous fat largely unchanged |
| Randomised trial | Extensions of 26 more weeks, with treatment kept up or stopped | Visceral fat came back once dosing stopped |
| Randomised trial | People with HIV and fatty liver disease (Lancet HIV, 2019) | Less liver fat |
| Licensed use | Egrifta, United States, approved 2010 | Indicated to reduce excess abdominal fat in HIV-associated lipodystrophy; IGF-1 is monitored |
For one population the ladder is complete, which is rare among research peptides. Subcutaneous fat barely changed, so the effect was specific to the visceral depot. IGF-1 was followed throughout, because more GH means more IGF-1, and some participants rose above the normal range. Glucose was watched as well, in a group already prone to insulin resistance.
The ladder does not extend sideways. Trial evidence is lacking for fat loss in HIV-negative people, for sports performance and for the anti-ageing purposes some sellers attach to tesamorelin.
Tesamorelin doses reported in studies
The figures below come from trial publications and from the US label. They are reference values, not guidance. They concern one patient group treated under medical supervision with laboratory monitoring, and say nothing about anyone else.
| Setting | Dose | Schedule | Route | Note |
|---|---|---|---|---|
| Phase 3 trials in adults with HIV (first published 2007) | 2 mg | Once a day for 26 weeks | Subcutaneous | CT measurement of visceral fat |
| Extensions of those trials | 2 mg, or withdrawal of treatment | Daily for 26 more weeks | Subcutaneous | Fat returned in those who stopped |
| HIV with fatty liver disease (Lancet HIV, 2019) | 2 mg | Once a day for 12 months | Not stated | Liver fat as endpoint |
| Egrifta label, United States | 2 mg | Once a day while treatment is indicated | Subcutaneous | Label advises IGF-1 checks |
Safety findings and open questions
A licensed product means documented safety data; what follows comes from the clinical programme and the US label. Redness, itching and pain at the injection site were among the most frequent complaints. Joint pain, muscle pain and swollen limbs occurred, as expected when GH output rises. IGF-1 exceeded the normal range in some participants; the label advises measuring it and reconsidering treatment if it stays high. The label also warns of worsening glucose control, describes rash and urticaria and, since GH and IGF-1 promote growth, cautions against treating anyone with an active malignancy.
- Does the visceral fat effect exist in people without HIV? The trials leave that unanswered.
- What is the balance of benefit and risk when the effect lasts only as long as treatment does?
- None of the label data describe a research vial, which has no regulated manufacturing dossier and no clinical oversight behind it.
Bench notes: storing and reconstituting Tesamorelin
Store the lyophilised powder at −20 °C, sealed, dry and dark. Give a cold vial time to reach room temperature before opening it; moisture that condenses on the powder shortens its life.
When a solution is needed, bacteriostatic water is the usual choice for a vial that will be sampled more than once, and King Peptides lists Bacteriostatic Water 10 ml. Let the solvent flow down the glass, swirl until clear and avoid shaking. Keep the solution refrigerated and out of the light, and split it into single portions for the freezer if the work will run on. The step-by-step version is in storage and reconstitution.
Status in the Netherlands, Belgium and Luxembourg
EU marketing authorisations come from the European Medicines Agency and apply in the Netherlands, Belgium and Luxembourg alike. Tesamorelin has none: the EMA has approved no product, and a European summary of product characteristics does not exist. The US approval dates from 2010 and covers HIV-associated lipodystrophy with excess abdominal fat. Egrifta is therefore not available as a medicine in the three countries. The molecule is a medicine in one jurisdiction; what is sold here under its name is research material without a licence, not meant for human use. National and institutional rules on possession and personal import differ and must be checked.
In sport, tesamorelin belongs to the GHRH analogues listed in section S2 of the WADA Prohibited List, which is in force at all times, in competition and out of it. GH secretagogues compared shows where the GHRH analogues stand next to ghrelin mimetics such as ipamorelin.
Ordering Tesamorelin for research in the Benelux
King Peptides lists the peptide as Tesamorelin 10 mg, so the product matches this profile exactly.
Chain length is the thing to keep in mind with the certificate of analysis. A 44-residue synthesis produces deletion and truncation by-products, chains with a residue missing or cut short. They resemble the target chemically and appear as shoulders and small satellite peaks beside the main peak. The lab reports page of the shop lists tesamorelin at an HPLC purity of 98% or higher, not the 99% or higher that applies to most of its products. The mass spectrum should show 5135.9 Da. A certificate with HPLC and mass spectrometry results accompanies every lot, and the lot number on it must match your vial. See checking a certificate of analysis.
Parcels leave the Netherlands with tracking and usually reach Dutch addresses in 1–2 business days and Belgium or Luxembourg in 3–5 business days. Inside the EU no customs clearance is involved. Buying research peptides in the Benelux covers the supplier checks.
Tesamorelin: quick answers
Is Egrifta sold in pharmacies in the Benelux? Not as an authorised medicine. Egrifta is licensed in the United States only; no EU marketing authorisation has been granted.
Why is IGF-1 measured with the licensed product? Tesamorelin raises GH, GH raises IGF-1, and some trial participants went above the normal range. The label therefore advises monitoring.
Tesamorelin or CJC-1295: what is the difference? Chain length and duration of action. Tesamorelin copies all 44 residues of GHRH, has a half-life well under an hour and was dosed daily. The DAC form of CJC-1295 is a 29-residue fragment that binds albumin and acts for days. Only tesamorelin has an approved medicine behind it; CJC-1295 development was discontinued.
Is a research vial the same as Egrifta? By name the molecule is the same. The product is not: a research vial carries no marketing authorisation, and the only document describing its contents is the certificate of analysis.
Research use only. This page describes Tesamorelin for laboratory and scientific research. Research material has no marketing authorisation, whatever the status of the molecule as a medicine elsewhere, and is not meant for human or veterinary use. Nothing on this page is medical advice; the doses above are those reported in published studies, not recommendations. Check the rules that apply in your country and at your institution before ordering.