GLP-1 (7-37) vs Tesamorelin

Binds GLP-1 receptors in the pancreas, gut, and brain. Stimulates glucose-dependent insulin secretion and suppresses glucagon. Central GLP-1 receptor activation reduces food intake via hypothalamic pathways.

GLP-1(7-37) is the native 30-amino-acid active form of glucagon-like peptide 1, an endogenous incretin hormone secreted by intestinal L-cells in response to nutrient ingestion, that acts at GLP-1 receptors throughout the body to stimulate glucose-dependent insulin secretion, suppress glucagon release, slow gastric emptying, reduce appetite, and protect beta-cell mass; it is the endogenous ligand underlying the pharmacology of the GLP-1 receptor agonist drug class. The GLP-1 receptor is expressed on pancreatic beta cells, hypothalamic appetite-regulating neurons, gastric enteric neurons, and cardiovascular tissue; GLP-1(7-37) activates cAMP/PKA signaling in beta cells to potentiate insulin release strictly during hyperglycemia, providing intrinsic hypoglycemia protection, and centrally reduces caloric intake through satiety signaling. A randomized controlled trial of continuous subcutaneous native GLP-1 infusion in patients with type 2 diabetes demonstrated significant reductions in plasma glucose and appetite, confirming receptor-mediated effects of the native peptide in humans; the peptide's very short plasma half-life of approximately 2 minutes due to rapid DPP-IV degradation makes continuous infusion the only practical administration route for the native form. Native GLP-1(7-37) has no FDA approval as a drug; FDA-approved GLP-1 receptor agonists — including semaglutide, liraglutide, dulaglutide, and tirzepatide — are chemically modified DPP-IV-resistant analogs developed to overcome the native peptide's pharmacokinetic limitations, and research-grade native GLP-1 is used exclusively as a tool compound in metabolic pharmacology studies.

Tesamorelin stimulates pulsatile GH secretion from the anterior pituitary by binding GHRH receptors. Its stabilisation protects it from rapid enzymatic cleavage by dipeptidyl peptidase IV, extending the effective half-life compared to unmodified GHRH. Downstream effects on visceral adiposity are mediated through elevated IGF-1 and direct lipolytic signalling.

Tesamorelin (GHRH(1-44)-trans-3-hexenoic acid; Egrifta) is a synthetic 44-amino-acid analog of endogenous growth hormone-releasing hormone conjugated with a trans-3-hexenoic acid moiety to confer resistance to DPP-IV enzymatic degradation and extend its plasma stability, developed and approved as the first GHRH analog indicated for a metabolic complication of HIV antiretroviral therapy — specifically visceral adiposity from HIV-associated lipodystrophy. Tesamorelin activates GHRH receptors on pituitary somatotrophs to stimulate pulsatile GH secretion and downstream hepatic IGF-1 production; the resulting normalization of GH pulse amplitude in treated patients reduces visceral adipose tissue through lipolytic signaling in visceral fat depots, without the risk of direct supraphysiological GH administration. A pivotal Phase 3 randomized placebo-controlled trial in HIV-infected adults on antiretroviral therapy demonstrated significant and sustained reductions in visceral adipose tissue area by MRI imaging versus placebo, with a favorable safety profile in this immunocompromised population, providing the pivotal evidence for FDA approval in 2010. Tesamorelin (Egrifta, Theratechnologies) is FDA-approved and requires a prescription; it is indicated specifically for the reduction of excess abdominal fat in HIV-infected patients with lipodystrophy and is not approved for general fat loss, body composition improvement, anti-aging, or GH deficiency applications outside the HIV-lipodystrophy indication. Tesamorelin dosage and where to get it: Tesamorelin (Egrifta) is administered as a once-daily subcutaneous injection of 2mg in its FDA-approved indication for HIV-associated lipodystrophy; this is the only dose and indication with established clinical evidence. In off-label research contexts examining body composition and GH axis support in non-HIV populations, tesamorelin has been studied at similar dose ranges, though no approved protocol exists for these applications. Where to find tesamorelin: as an FDA-approved prescription medication, tesamorelin is available through licensed pharmacies in the United States with a valid prescription. Compounding pharmacies may also prepare tesamorelin for off-label clinical use under physician supervision. Telehealth providers specializing in peptide therapy and hormone health sometimes offer tesamorelin consultations for eligible patients. PeptideBase maintains a directory of verified providers — including telehealth platforms — for those researching access to tesamorelin through supervised clinical channels.