Tesamorelin is a synthetic growth hormone–releasing hormone (GHRH) analog designed to stimulate endogenous growth hormone secretion through the pituitary. It is best known clinically as the active ingredient in Egrifta, which is FDA-approved in the United States to reduce excess abdominal visceral fat in adults with HIV-associated lipodystrophy. Beyond that approved use, tesamorelin has also been studied in metabolic and liver-fat research settings.

Tesamorelin is a 44-amino-acid peptide analog of human GHRH with modifications that improve stability and pharmacokinetics relative to native GHRH. Its primary action is at the GHRH receptor in the anterior pituitary, where it promotes release of endogenous growth hormone and downstream increases in IGF-1. This endocrine profile is a major reason tesamorelin is studied in body-composition and metabolic models.

Tesamorelin has been explored in research involving:

* Growth hormone axis stimulation
* Visceral adiposity and body-composition models
* HIV-associated lipodystrophy
* Liver-fat and metabolic-health research
* IGF-1 and endocrine pathway studies

In both clinical and translational research, tesamorelin is most strongly associated with visceral fat reduction and broader metabolic signaling rather than general weight-loss use. MedlinePlus specifically notes that tesamorelin is used to reduce extra abdominal fat in adults with HIV-associated lipodystrophy.

Tesamorelin works by activating pituitary GHRH receptors, which increases synthesis and release of endogenous growth hormone. The resulting rise in growth hormone contributes to higher IGF-1 levels and downstream effects on lipolysis, body composition, and metabolic processes. In published literature, this mechanism is frequently discussed in the context of preferential effects on visceral adipose tissue rather than nonspecific total-body weight reduction.

Clinical and translational studies have shown that tesamorelin can reduce visceral abdominal fat in patients with HIV-associated lipodystrophy. Additional published work has examined its effects on liver fat, with one JAMA study reporting that six months of tesamorelin was associated with reductions in visceral fat and modest reductions in liver fat in HIV-infected patients with abdominal fat accumulation. Reviews also note its continued investigation in obesity, insulin-resistance, and NAFLD-related research, though its approved clinical indication remains HIV-associated lipodystrophy.

Falutz, J., Mamputu, J. C., Potvin, D., Moyle, G., Soulban, G., Loughrey, H., Marsolais, C., et al. (2010). Effects of tesamorelin (TH9507), a growth hormone-releasing factor analog, in HIV-infected patients with excess abdominal fat: a pooled analysis of two multicenter, double-blind placebo-controlled phase 3 trials with safety extension data. Journal of Clinical Endocrinology & Metabolism, 95(9), 4291–4304. PMID: 20554713.

Falutz, J., Potvin, D., Mamputu, J. C., Assaad, H., Zoltowska, M., Michaud, S. E., Berger, D., et al. (2010). Effects of tesamorelin, a growth hormone-releasing factor, in HIV-infected patients with abdominal fat accumulation: a randomized placebo-controlled trial with a safety extension. Journal of Acquired Immune Deficiency Syndromes, 53(3), 311–322. PMID: 20101189.

Stanley, T. L., Fourman, L. T., Feldpausch, M. N., et al. (2014). Effect of tesamorelin on visceral fat and liver fat in HIV-infected patients with abdominal fat accumulation: a randomized clinical trial. JAMA, 312(4), 380–389.

Adrian, S., & Grinspoon, S. K. (2019). The growth hormone releasing hormone analogue tesamorelin in the treatment of HIV-associated lipodystrophy. Expert Review of Endocrinology & Metabolism, 14(3), 173–182. This review summarizes mechanism, metabolic context, and clinical role.

Dhillon, S. (2021). Tesamorelin: A review in HIV-associated lipodystrophy. Drugs. This is a useful review source for the approved indication and broader clinical positioning.