Sermorelin vs Tesamorelin
Sermorelin and tesamorelin are both growth hormone-releasing hormone (GHRH) analogs, but they differ in length, stability, and research pedigree. Sermorelin is the minimal functional GHRH fragment, while tesamorelin is a stabilized full-length analog with completed phase 3 programs.
Side-by-Side Comparison
| Property | Sermorelin | Tesamorelin |
|---|---|---|
| Category | GHRH(1-29) analog (shortest fully active GHRH fragment) | Stabilized full-length GHRH(1-44) analog (trans-3-hexenoyl modification) |
| Mechanism of Action | Binds GHRH receptor on pituitary somatotrophs; stimulates physiological, pulsatile GH secretion | Binds GHRH receptor; the N-terminal hexenoyl group confers resistance to DPP-4 degradation, extending activity |
| Molecular Weight | ~3,358 Da (29 amino acids) | ~5,136 Da (44 amino acids + hexenoyl moiety) |
| Primary Research Focus | GH axis physiology, GH deficiency models (formerly marketed as Geref) | Visceral adipose tissue reduction; approved (Egrifta) for HIV-associated lipodystrophy; liver fat research |
| Receptor Target | GHRH receptor | GHRH receptor |
| Half-Life | ~10-20 minutes | ~26-38 minutes |
| Key Research Citations | Prakash & Goa (1999), BioDrugs; Walker (2006), Clin Interv Aging | Falutz et al. (2007), NEJM; Stanley et al. (2014), JAMA |
Key Differences
- Sermorelin is the truncated GHRH(1-29) fragment, the shortest sequence retaining full receptor activity; tesamorelin keeps all 44 residues and adds a stabilizing hexenoyl group.
- Tesamorelin’s DPP-4 resistance roughly doubles its half-life relative to sermorelin, though both remain short-acting compared to DAC-modified analogs.
- Tesamorelin carries phase 3 evidence and regulatory approval for visceral fat reduction in HIV lipodystrophy; sermorelin’s clinical history is in GH deficiency diagnosis and treatment.
- Research applications differ accordingly: sermorelin appears in GH-axis physiology studies, tesamorelin in body-composition and hepatic fat research.
Research Summary
Sermorelin and tesamorelin engage the same GHRH receptor but represent different design choices. Sermorelin strips GHRH to its minimal active fragment, producing a short-acting tool for studying physiological GH pulsatility. Tesamorelin preserves the full-length sequence and armors it against DPP-4 degradation, yielding a longer-acting analog whose phase 3 programs demonstrated selective visceral adipose reduction. Both preserve the natural pulsatile pattern of GH release, distinguishing GHRH analogs from direct GH administration.
What is the difference between sermorelin and tesamorelin?
Both are GHRH receptor agonists. Sermorelin is the minimal GHRH(1-29) fragment with a ~10-20 minute half-life, historically used in GH deficiency. Tesamorelin is a full-length GHRH(1-44) analog stabilized against DPP-4 degradation, with a longer half-life and phase 3 evidence for visceral fat reduction in HIV-associated lipodystrophy.
More Comparisons
Disclaimer: All compounds referenced on this page are sold for research and laboratory use only. The comparisons presented are based on published scientific literature and are intended for educational and informational purposes. This content does not constitute medical advice. Researchers should consult primary literature and applicable regulations before designing study protocols.