At a glance

What is tesamorelin?

Tesamorelin, sold under the brand Egrifta, is a stabilized synthetic analog of growth hormone-releasing hormone (GHRH), the hypothalamic signal that tells the pituitary to release growth hormone. It is used specifically for the deep abdominal fat that can accumulate in people with HIV, a condition called lipodystrophy. It was developed under the code TH9507 and approved in the United States in 2010.

How does tesamorelin work?

Tesamorelin binds GHRH receptors on the pituitary and stimulates the gland to release its own growth hormone in a natural, pulsatile pattern, which in turn raises insulin-like growth factor 1. One of growth hormone's effects is lipolysis, the breakdown of fat, and visceral (intra-abdominal) fat is particularly responsive. By boosting the body's own growth hormone rather than supplying growth hormone directly, tesamorelin reduces that deep abdominal fat.

The table below shows how visceral adipose tissue¹ changed in the HIV lipodystrophy trials.

The fat tends to return if treatment stops, because the underlying driver is unchanged.

Is it FDA-approved?

Yes. Tesamorelin was approved² by the FDA in 2010 as Egrifta, with later formulations marketed as Egrifta SV and Egrifta WR. It is given as a daily subcutaneous injection.

What is tesamorelin prescribed for?

Tesamorelin is prescribed to reduce excess abdominal fat in people with HIV-associated lipodystrophy. It is not approved for general weight loss, and it is contraindicated:

• In pregnancy
• In active cancer
• When the pituitary axis has been disrupted

What are the side effects?

According to the prescribing information, common side effects include:

• Injection-site reactions
• Joint, muscle, and limb pain
• Swelling from fluid retention

More serious considerations include:

• Higher blood sugar and glucose intolerance
• Fluid retention
• An increased risk of new tumors, so any existing cancer should be inactive and fully treated before starting
• Raised IGF-1 levels, which are monitored during treatment
• Allergic reactions

Frequently asked questions

What is tesamorelin used for?

Tesamorelin (Egrifta SV) is FDA-approved for the reduction of excess abdominal fat in adults with HIV-associated lipodystrophy. Researchers have also studied tesamorelin in non-HIV populations with visceral adiposity³ and HIV-associated non-alcoholic fatty liver disease⁴, but these uses are not FDA-approved indications. Any prescribing outside the approved indication is the independent clinical judgment of the provider.

How long does it take for tesamorelin to reduce visceral fat?

In the pivotal Phase III trials, statistically significant and clinically meaningful visceral fat reductions were documented at 26 weeks of treatment compared to placebo. One trial in 412 adults with HIV reported a 15.2% VAT reduction⁵ with tesamorelin versus a 5.0% increase with placebo (p < 0.001), and a pooled analysis of 806 adults reported a treatment effect of approximately -15.4%⁶ at 26 weeks. Extension trial data confirmed that visceral fat returns toward baseline after discontinuation⁷, so continued use is associated with sustained effect.

Does tesamorelin affect blood sugar?

Growth hormone has counter-regulatory effects on insulin sensitivity, meaning it can raise fasting glucose and reduce insulin sensitivity at elevated GH levels. In pooled pivotal trials of 806 adults with HIV, tesamorelin was generally well tolerated, with no clinically meaningful between-group differences in glucose parameters⁶. A 12-week randomized trial in 53 adults with type 2 diabetes found no significant differences in fasting glucose⁸ or insulin response between tesamorelin and placebo arms. Across the clinical trials, though, an HbA1c of 6.5% or higher⁹ by week 26 was more common with tesamorelin than placebo (5% vs 1%). Providers evaluate glucose before starting tesamorelin and monitor it periodically during therapy.

What is the difference between tesamorelin and sermorelin?

Tesamorelin is a full-length GHRH(1-44) analog stabilized with a trans-3-hexenoyl modification at the N-terminus, giving it resistance to DPP-IV degradation¹⁰. It is FDA-approved for HIV-associated lipodystrophy with multiple Phase III RCTs demonstrating visceral fat reduction. Sermorelin is a shorter GHRH(1-29) fragment comprising the minimum active sequence without N-terminal stabilization. Sermorelin is not currently FDA-approved (its earlier approval as Geref ended after discontinuation) and has a substantially smaller clinical evidence base. No head-to-head trial comparing the two compounds has been published.

Who should not take tesamorelin?

Contraindications include disruption of the hypothalamic-pituitary axis (hypopituitarism, pituitary tumor, prior head irradiation, head trauma), active malignancy, pregnancy, and known hypersensitivity to tesamorelin or its components. A provider will conduct a complete clinical evaluation before prescribing.

Does tesamorelin cause side effects?

The most commonly reported side effects in Phase III trials were injection-site reactions (erythema, pruritus, pain)⁹, arthralgia, pain in the extremities, myalgia, peripheral edema, and paresthesia. These are broadly consistent with GH-class effects and local subcutaneous injection reactions. Injection-site reactions were the most frequently reported individual adverse event. Glucose dysregulation and IGF-1 elevation above the reference range are metabolic effects requiring monitoring. Hypersensitivity reactions occurred in 4% of trial patients and warrant prompt provider contact.

How long does tesamorelin need to be taken for the effect to persist?

A 12-month trial with an extension phase found that visceral fat reduction is sustained⁷ with continued tesamorelin use and that visceral adipose tissue returns toward baseline values after discontinuation. This indicates that the medication requires continued use to maintain the visceral fat reduction effect. Providers assess the risk-benefit balance of long-term use on an individual basis, taking into account metabolic monitoring results, IGF-1 levels, and overall clinical response.

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