What it is
Tesamorelin is a synthetic version of growth hormone-releasing hormone (GHRH), the hypothalamic signal that tells the pituitary to release growth hormone. Unlike sermorelin and CJC-1295, which use only the first 29 amino acids, tesamorelin keeps all 44. A hexenoyl group is attached to the first amino acid, a tyrosine, to protect it from breakdown.
It is the only GHRH analogue with a current FDA approval. Theratechnologies developed it as TH9507, and the US FDA approved it in 2010 as Egrifta to reduce excess abdominal fat in adults with HIV-associated lipodystrophy. Newer formulations followed: Egrifta SV, and Egrifta WR, approved in March 2025, whose mixed solution can be used for up to seven days.
How it works
Tesamorelin binds GHRH receptors on the pituitary and triggers a pulse of growth hormone. GH raises IGF-1 and, importantly for its approved use, promotes breakdown of fat stored around the abdominal organs. In the 2007 trial, IGF-1 rose 81% on tesamorelin.
Because it acts through the pituitary, somatostatin feedback still applies, and GH release stays pulsatile. The label half-life is short: 26 minutes in healthy subjects and 38 minutes in HIV patients for the original formulation, and 8 to 11 minutes for the newer ones. The effect is a daily pulse, not a sustained level.
What the research found
Human studies
Falutz and colleagues (2007, NEJM) randomised 412 adults with HIV and abdominal fat accumulation to 2 mg tesamorelin or placebo daily for 26 weeks. Visceral fat was measured by CT scan.
- visceral fat fell 15.2% on tesamorelin and rose 5.0% on placebo
- triglycerides fell 50 mg/dL on tesamorelin and rose 9 mg/dL on placebo
- IGF-1 rose 81%
The FDA label pools the two Phase 3 trials, which together treated 740 patients with HIV. In the first, visceral fat area fell 27 cm² on tesamorelin vs a 4 cm² rise on placebo; in the second, it fell 21 cm² vs no change.
Stanley and colleagues (2019, Lancet HIV) tested tesamorelin in 61 adults with HIV and fatty liver disease (liver fat fraction of 5% or more) for 12 months.
- liver fat fraction fell by an absolute 4.1% more than placebo, a 37% relative reduction
- 35% of the tesamorelin group reached normal liver fat (under 5%), against 4% on placebo
- glucose measures did not differ between groups
The approved use is narrow. The label states tesamorelin is not indicated for weight loss, and its long-term cardiovascular safety has not been established.
Side effects reported in studies
The FDA label lists these as the most common adverse reactions, each above 5%:
- joint pain
- redness and itching at the injection site
- pain in the arms or legs
- swelling of the legs and feet
- muscle pain
The label's warnings cover a possible increased risk of tumours, raised IGF-1, fluid retention, glucose intolerance or diabetes, allergic reactions, injection site reactions, and increased mortality in acutely critically ill patients. The original label advises monitoring IGF-1 closely and checking glucose status before and during treatment. It is contraindicated in pregnancy, active malignancy, and conditions that disrupt the hypothalamic-pituitary axis.
In the liver fat trial, two participants on tesamorelin withdrew because of high blood sugar.
Tesamorelin vs sermorelin
| Tesamorelin | Sermorelin | |
|---|---|---|
| Structure | Full 44 amino acid GHRH, hexenoyl-modified | First 29 amino acids, unmodified |
| Half-life | 8 to 38 minutes (label) | Minutes |
| Approval | FDA-approved (Egrifta), current | US brand Geref withdrawn 2008 |
| Largest trial | Phase 3, 412 adults with HIV | Small ageing studies |
For a longer comparison see tesamorelin vs sermorelin.
Status in the Philippines
We could not identify an FDA Philippines registration for Egrifta or any other tesamorelin product, so it is not available here as a prescription medicine. It is not a controlled substance under RA 9165. Locally it circulates through research-chemical suppliers as a freeze-dried powder, which is not the approved product. Because tesamorelin is an approved medicine abroad, prescribing belongs with a licensed Philippine physician. The trials and label track IGF-1 and glucose; see bloodwork in the Philippines.
Local stock Tesamorelin 10mg at Primara Labs, delivered in Metro Manila and nationwide. Research use only.
Storage
The current US label for Egrifta WR stores the vials at room temperature, 20 to 25°C, protected from light, not frozen, with mixed solution discarded after seven days. Philippine room temperature often runs above 25°C, and research-grade powder is not the labelled product, so refrigeration after mixing is the cautious default. For mixing arithmetic, see the tesamorelin calculator.
