Sermorelin Peptide Potential as a Growth Hormone Secretagogue

Sermorelin Acetate, a synthetic peptide, was developed to function as an analog of a naturally occurring hormone called growth hormone-releasing hormone (GHRH). While GHRH has 44 amino acids, Sermorelin peptide is truncated down to 29 amino acids. Sermorelin peptide is also known as the Growth Hormone Releasing Factor (1-29) or GRF (1-29). Sermorelin is the smallest fragment of the GHRH chain that appears to possess the same functions, namely, stimulating the pulsatile release of growth hormone (HGH) by the pituitary gland. Due to this potential, Sermorelin peptide has been classified by researchers as a Growth Hormone Secretagogue (GHS). Like GHRH and other GHSs, Sermorelin may possibly increase the production of HGH in the pituitary gland, resulting in higher and more frequent peaks of the growth hormones. This would also result in elevated levels of Insulin Growth Factor-1 (IGF-1), a primary anabolic mediator.

 

What is the Sermorelin?

Sermorelin was first synthesized in the early 1980s and has been avidly researched since its development. It is made of 29 amino acids and bears the sequence YADAXFXNSYRKVLGQLSARKLLQDXMSR. Sermorelin peptide, aka GRF (1-29), should not be confused with Modified GRF (1-29), which has 4 of the original 29 amino acids replaced with the intent to increase its half-life from 10 to 30 minutes.

 

General Research in Sermorelin

 

Sermorelin Peptide and the Endocrine System

As a GHRH analog, Sermorelin peptide has been researched primarily for its potential to stimulate pulsatile hGH synthesis via the pituitary gland. Studies observed that as long as the pituitary gland is functioning correctly, Sermorelin, combined with the amino acid Arginine, may induce a significant spike in serum HGH levels.^[1] Studies in research models of growth failure also report that Sermorelin peptide appeared to increase growth velocity with growth failure and functional pituitary glands by 74%.^[2] Further research reported that 6 months of either Sermorelin peptide or hGH exposure, appeared to exhibit a similar increase in growth velocity.^[3] Studies also reported an apparent significant increase in serum HGH levels after several days of Sermorelin peptide introduction.^[4]

The peptide may also affect the levels of other hormones apart from HGH, such as insulin and sex hormones.  Although high hGH is often associated with increased insulin levels and insulin resistance, one 16-week trial suggested that Sermorelin may improve insulin sensitivity in males but not in female organisms.^[5]  One animal trial reported an increase in gonadotropic hormones and testosterone levels in male mice, but there is no clinical research to support these findings.^[6]

 

Sermorelin Studies in Cardiovascular Function

Sermorelin may impact cardiovascular functioning due to its apparent HGH-stimulating potential.^[7] Researchers suggest, “That GHRH analog [exposure] induced anabolic effects favoring [male species] more than [female]. Further studies are needed to define the gender differences observed in response to GHRH analog [exposure].”^[8]

 

Sermorelin Peptide and Extracellular Matrix

Scientists posit that Sermorelin has the potential to function in increasing HGH levels. From this assumption, it may be possible for Sermorelin peptide to increase the proliferation of new skin cells, ultimately leading to increased collagen deposition inside the derma.

One study focusing on male species reported that 4 months of Sermorelin peptide exposure appeared to significantly increase their skin thickness.^[11] Additionally, the males, but not the female organisms, also expressed increased libido and related behaviors.

 

Sermorelin Peptide and the Nervous System

One study suggested that even a one-time exposure to Sermorelin peptide may support improvements in short-term memory.^[12] In fact, researchers reported that the effect on memory recall appeared more significant in Sermorelin-exposed research models than those given a placebo. There is also mixed data regarding the potential of Sermorelin peptide on brain tumors. One experiment reports that Sermorelin peptide may speed up the development of neuroendocrine tumors such as pituitary adenomas due to its possible growth-promoting effect.^[13] However, a study in gliomas reported the opposite effect, observing that the peptide appeared to suppress the recurrence of the tumors.^[14]

 

Conclusion

Sermorelin may hold significant research potential as a Growth Hormone Secretagogue (GSH). This is supported by research findings indicating that when exposed to Sermorelin, animal research models’ serum growth hormone levels might not exceed the physiological limits exerted by somatostatin.

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References

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6. Chatelain PG, Sanchez P, Saez JM. Growth hormone and insulin-like growth factor I treatment increase testicular luteinizing hormone receptors and steroidogenic responsiveness of growth hormone deficient dwarf mice. Endocrinology. 1991 Apr;128(4):1857-62. doi: 10.1210/endo-128-4-1857. PMID: 2004605.
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9. Corpas E, Harman SM, Piñeyro MA, Roberson R, Blackman MR. Growth hormone (GH)-releasing hormone-(1-29) twice daily reverses the decreased GH and insulin-like growth factor-I levels in old men. J Clin Endocrinol Metab. 1992 Aug;75(2):530-5. doi: 10.1210/jcem.75.2.1379256. PMID: 1379256.
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11. Khorram O, Laughlin GA, Yen SS. Endocrine and metabolic effects of long-term administration of [Nle27]growth hormone-releasing hormone-(1-29)-NH2 in age-advanced men and women. J Clin Endocrinol Metab. 1997 May;82(5):1472-9. doi: 10.1210/jcem.82.5.3943. PMID: 9141536.
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13. Stepień T, Sacewicz M, Lawnicka H, Krupiński R, Komorowski J, Siejka A, Stepień H. Stimulatory effect of growth hormone-releasing hormone (GHRH(1-29)NH2) on the proliferation, VEGF and chromogranin A secretion by human neuroendocrine tumor cell line NCI-H727 in vitro. Neuropeptides. 2009 Oct;43(5):397-400. doi: 10.1016/j.npep.2009.08.005. Epub 2009 Sep 10. PMID: 19747727.
14. Chang Y, Huang R, Zhai Y, Huang L, Feng Y, Wang D, Chai R, Zhang W, Hu H. A potentially effective drug for patients with recurrent glioma: sermorelin. Ann Transl Med. 2021 Mar;9(5):406. doi: 10.21037/atm-20-6561. PMID: 33842627; PMCID: PMC8033379.