Tesamorelin: the GHRH peptide.

Tesamorelin is a synthetic version of growth hormone releasing hormone — the natural signal your brain sends to tell your pituitary gland to release growth hormone. It is one of the few peptides in the broader category that has full FDA approval for a specific clinical indication.

What it actually does

Your body produces growth hormone (GH) in pulses throughout the day and night, most prominently during deep sleep. The pituitary gland releases GH in response to signals from the hypothalamus — and the main signal is a natural peptide called growth hormone releasing hormone, or GHRH.

Tesamorelin is a synthetic analog of GHRH — essentially a slightly modified version designed to be more stable in the bloodstream than the natural hormone. When introduced, it binds the same receptors GHRH would, prompting the pituitary to release growth hormone in a similar pattern to natural pulses. It does not introduce GH directly — it asks your own pituitary to do it.

The approved use

Tesamorelin is FDA-approved under the brand name Egrifta for reducing excess abdominal fat in adults with HIV-associated lipodystrophy — a specific medical condition where antiretroviral therapy can cause unusual fat accumulation in the abdomen.

That is a narrow approved indication, but the clinical trials that supported approval included substantial evidence for visceral (deep abdominal) fat reduction, which is part of why tesamorelin has drawn broader interest beyond its specific approval.

What research has explored

Beyond the approved indication, tesamorelin has been investigated in a number of contexts:

• Visceral fat reduction — the most-studied effect, with consistent reductions in deep abdominal fat across trials.
• IGF-1 increases — reliable increases in insulin-like growth factor 1, the downstream marker of GH activity.
• Lipid profile changes — improvements in triglycerides and other markers in some studies.
• Cognitive function in aging — small studies have looked at GHRH analogs (including tesamorelin) for cognitive effects in older adults.
• Body composition — increases in lean mass alongside fat reduction in some studies.

Where it sits

Tesamorelin is a useful reference point in the growth hormone peptide category. It works upstream — prompting your own pituitary to do what it already knows how to do — rather than introducing synthetic growth hormone directly. That mechanism, combined with its actual FDA approval (however narrow), puts it in a different category from most GHRH-related research peptides.

If you want the math for tesamorelin reconstitution, the calculator handles it (a 10mg vial in 2mL with a 1mg daily reference is a common starting point). And the peptide library shows how it sits alongside other growth-hormone-axis compounds like ipamorelin and CJC-1295.