What is Tesamorelin?
Tesamorelin is a synthetic 44–amino-acid analogue of human growth hormone–releasing hormone (GHRH), featuring an N-terminal trans‑3‑hexenoic acid modification that enhances its stability and receptor affinity. It functions as a GHRH receptor agonist to stimulate endogenous, pulsatile growth hormone release, making it a powerful research tool for examining pituitary signaling, metabolic regulation, and body composition responses.
 
Chemical Structure of Tesamorelin
Tesamorelin comprises the 44–residue GHRH peptide sequence with a trans‑3‑hexenoic acid moiety attached to the N‑terminal tyrosine. Its molecular formula is approximately C₂₂₁H₃₆₆N₇₂O₆₇S, and molecular weight is around 5,136 Da, as recorded in PubChem (CID 146681838).
 
What Are the Effects of Tesamorelin?
Endogenous GH–IGF-1 Axis Activation: Tesamorelin binds pituitary GHRH receptors, leading to physiological GH secretion and subsequent IGF‑1 synthesis; this activation preserves natural feedback loops while avoiding supraphysiologic GH surges.
Mitochondrial Function & Bioenergetics: In obese subjects, a 12‑month treatment correlating increases in IGF‑1 with improved phosphocreatine recovery, indicating better mitochondrial oxidative capacity.
Visceral Fat Reduction & Metabolic Modulation: Clinical trials demonstrate 15–20% reductions in visceral adipose tissue over 26–52 weeks, along with enhanced lipid metabolism and liver fat clearance.
Insulin Sensitivity & Lipid Homeostasis: Tesamorelin has been shown to improve glucose handling and lower triglyceride levels in individuals with fat accumulation syndromes.
Expanded Research Applications: Current investigation extends its use to study cognitive aging, sarcopenia, neuroprotection, and metabolic resilience in preclinical and clinical models.
 
Citations
PubChem Compound Summary for Tesamorelin (CID 146681838): molecular formula C₂₂₁H₃₆₆N₇₂O₆₇S; MW 5,136 Da. 
Peptides.guide entry on Tesamorelin: 44-amino-acid GHRH analogue with trans‑3‑hexenoic acid N‑terminus. 
PeptideSciences Research Review: tesamorelin restores GH pulsatility to reduce visceral fat, modulate metabolism, and enhance liver health. 
Research Peptides summary: tesamorelin researched for GH and IGF‑1 stimulation, fat metabolism, muscle growth. 
C. Grinspoon et al. “The Effects of Tesamorelin on Phosphocreatine Recovery in Obese Subjects With Reduced GH.” J Clin Endocrinol Metab. 2014;99(1):338–343. PMID: 24142878. 
J. Falutz et al. “Effects of tesamorelin (TH9507), a growth hormone–releasing factor analog, in HIV‑infected patients with excess abdominal fat: a pooled analysis of two phase 3 trials.” J Clin Endocrinol Metab. 2010;95(9):4291–4304. PMID: 20656618.