Tesamorelin is a synthetic analog of growth hormone-releasing factor (GHRH) made up of 44 amino acids. Its differentiating feature is the addition of a trans-3-hexenoyl group at the N-terminus, a modification that confers resistance to degradation by DPP-4 and prolongs its half-life.
Mechanism of action
Tesamorelin binds to the GHRH-R receptor on somatotrophs of the anterior pituitary, stimulating pulsatile growth hormone release. Unlike direct administration of recombinant GH:
- It preserves the physiological pulsatility of GH secretion.
- It is subject to negative feedback by somatostatin and IGF-1, which reduces the risk of supraphysiological levels.
- The resulting increase in IGF-1 is usually moderate (15–30% above baseline).
Most relevant research
The main line of research with tesamorelin has focused on redistribution of visceral adipose tissue. Published phase 3 studies in patients with antiretroviral therapy-associated lipodystrophy showed:
- An average 15–18% reduction in abdominal visceral fat measured by CT at 26 weeks.
- Improvement of the triglyceride profile and the adiponectin/leptin ratio.
- Reduction of liver fat content in a sub-cohort with steatosis.
The data cited correspond to clinical trials in specific populations and cannot be extrapolated to general use. Tesamorelin in the NeoPeptidos catalog is for laboratory research.
Comparison with other GHRH analogs
Compared with CJC-1295 (also a GHRH analog):
- Tesamorelin: 44 amino acids, half-life of hours, requires daily dosing.
- CJC-1295 with DAC: 30 amino acids, half-life of days, weekly dosing.
- CJC-1295 without DAC: 29 amino acids, short half-life (~30 min), allows the study of individual GH pulses.
Frequent endpoints in preclinical studies
- CT or MRI to quantify visceral fat.
- Serum IGF-1 (it should increase to confirm the axis response).
- Full lipid profile.
- Liver markers (ALT, AST, triglyceride content by spectroscopy).
- Insulin sensitivity markers (HOMA-IR, euglycemic clamp).
Pharmacokinetic considerations
Half-life in humans: approximately 26 minutes after subcutaneous administration. Subcutaneous bioavailability is on the order of 4%, but enough to induce a reproducible GH pulse that translates into a measurable rise in IGF-1 at 4–8 hours.
Storage
Lyophilized and refrigerated (2–8 °C), tesamorelin is stable for at least 18 months. After reconstitution with bacteriostatic water, shelf life is 28 days refrigerated.
Conclusion
Tesamorelin is one of the GHRH analogs with the most characterized clinical profile, particularly in the context of visceral fat redistribution. For preclinical metabolic research, it is a solid tool when the goal is to stimulate the somatotropic axis physiologically (pulsatile) without resorting to recombinant GH.
🔬 Updated on April 2, 2026 · Reviewed by the NeoPeptidos team · Content for research purposes (RUO).