Tesamorelin is an analog of human growth hormone-releasing factor (GRF). The peptide precursor of tesamorelin acetate is produced synthetically and is comprised of the 44 amino acid sequence of human GRF. In vitro, tesamorelin binds and stimulates human GRF receptors with similar potency as the endogenous GRF. GRF, also known as growth hormone-releasing hormone (GHRH), is a hypothalamic peptide that acts on the pituitary somatotroph cells to stimulate the synthesis and pulsatile release of endogenous growth hormone (GH), which is both anabolic and lipolytic. GH exerts its effects by interacting with specific receptors on a variety of target cells, including chondrocytes, osteoblasts, myocytes, hepatocytes, and adipocytes, resulting in a host of pharmacodynamic effects. Some, but not all these effects, are primarily mediated by IGF-1 produced in the liver and in peripheral tissues. Tesamorelin is the first and, so far, only treatment indicated for the reduction of excess abdominal fat in patients with HIV-associated lipodystrophy. Tesamorelin is effective in improving visceral adiposity and body image in patients with HIV-associated lipodystrophy over 26-52 weeks of treatment. Potential limitations for its use include high cost and lack of long-term safety and adherence data. Tesamorelin provides a useful treatment option for management of patients with significant lipodystrophy related to HIV infection.

Sermorelin, a 29 amino acid analog of human growth hormone-releasing hormone (GHRH), is the shortest synthetic peptide with a full biological activity of GHRH which is used as a diagnostic agent to assess growth hormone (GH) secretion for the purpose of diagnosing growth hormone deficiency. Intravenous and subcutaneous sermorelin specifically stimulate growth hormone secretion from the anterior pituitary. Sermorelin binds to the growth hormone releasing hormone receptor and mimics native GRF in its ability to stimulate growth hormone secretion. Hormone responses to intravenous sermorelin appear to be a rapid and relatively specific test for the diagnosis of growth hormone deficiency.