Sermorelin: A great peptide?

Sermorelin is a synthetic analogue of the naturally occurring hormone known as growth hormone releasing hormone (GHRH). Sermorelin is used as a diagnostic agent in clinical medicine to assess growth hormone secretion. It is known by the trade name Geref and also by the name Growth Hormone Releasing Factor (1-29), which is abbreviated to GRF (1-29).

Structure and Function

Sermorelin consists of the first 29 amino acids of GHRH. Research in the early 1980s demonstrated that the first 29 amino acids of the full GHRH peptide (44 amino acids long) were capable of eliciting a full growth hormone (GH) response from the anterior pituitary gland. The shortened sermorelin has a limited half-life compared to GHRH, which means that it is cleared from the blood stream quickly. The short half-life of sermorelin makes it an ideal molecule for testing GH release because it does not have long-lasting effects and thus is relatively benign.

In limited cases, sermorelin is useful in treating growth hormone deficiency. In general, the peptide is used in adult-onset GH deficiency and rarely to treat childhood forms of the disorder. GH deficient children will not experience a large enough improvement in GH secretion when only secretagogues like sermorelin are used. Instead, children often require direct supplementation with GH. Recently, sermorelin has seen increased use in longevity medicine, a specialty focusing on improving physical performance and health in the elderly1 .

Amino Acid Sequence of Sermorelin:


Amino Acid Sequence of GHRH:

Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg -Lys-Leu-Leu-Gln-Asp-Ile -Met-Ser-Arg-Gln-Gln-Gly-Glu-Ser-Asn-Gln-Glu-Arg-Gly-Ala-Arg-Ala-Arg-Leu-NH2

Effects of Sermorelin

Because sermorelin causes the release of GH from the anterior pituitary gland, it mimics effects of any other GH secretagogue. Examples of sermorelin effects include

.   Increased released of insulin-like growth factor-1 (IGF-1) from the liver,

.   Increases in muscle mass and bone density via both hypertrophy (cell size increases) and hyperplasia (increases in numbers of cells),

.   Increased fat metabolism and weight loss,

.   Improved cardiovascular function,

.   Improved renal function, and

.   Improved cognitive function.


The drug is not prohibited for use in off-label prescribing, which means that it can be prescribed by physicians for uses other than what it is specifically marketed for. This contrasts markedly with GH, which can only be prescribed for a fixed number of conditions and cannot legally be used off label.

Benefits of Sermorelin over Growth Hormone

One of the reasons that sermorelin has become popular in adults is that it has fewer side effects than GH. In particular, overdoses with sermorelin are extremely uncommon because its effects are still subject to normal negative feedback mechanisms that control endogenous GHRH. Other benefits of sermorelin include mimicking normal physiologic release of GH, low risk of tachyphylaxis (rapidly diminishing response to successive doses of a drug), and preservation of the GH neuroendocrine axis1 . Get full information at


  1. Walker, R. F. Sermorelin: A better approach to management of adult-onset growth hormone insufficiency? Clin. Interv. Aging1, 307-308 (2006).