Sermorelin

This review consolidates the pharmacology and clinical research literature on Sermorelin — characterized as a 29-amino-acid analog of human GHRH and the shortest synthetic peptide with full biological activity of GHRH. The authors describe that intravenous and subcutaneous Sermorelin specifically stimulate growth hormone secretion from the anterior pituitary somatotrophs via the GHRH receptor, with peak GH responses typically observed 15–60 minutes after administration. Single-dose intravenous Sermorelin at 1 μg/kg bodyweight is reviewed as a relatively specific provocative test for the diagnosis of GH deficiency, with fewer false positives in children without GH deficiency compared with several conventional provocative tests. The review summarizes clinical research in which once-daily subcutaneous Sermorelin at 30 μg/kg bodyweight at bedtime produced sustained increases in height velocity over 12 months in prepubertal children with idiopathic GH deficiency, with data from a smaller subset suggesting maintenance of effect through 36 months. The authors note that increases in height velocity from baseline with Sermorelin were generally smaller than those reported with once-daily subcutaneous somatropin, and that transient facial flushing and injection-site pain were the most commonly reported adverse events.

This is a comprehensive review article that pulls together what was known about Sermorelin by 1999. The authors explain that Sermorelin is essentially the "business end" of the body's natural GHRH hormone — the first 29 amino acids, which is all you need to flip the pituitary's growth-hormone switch. They review studies showing that a single small dose can be used as a diagnostic probe to see whether a child's pituitary is capable of releasing growth hormone. They also summarize trials in which children with growth hormone deficiency received daily bedtime injections and grew faster over the year that followed. Side effects were mostly mild — flushing of the face and soreness where the needle went in.

This multicenter, open-label clinical study enrolled 110 previously untreated prepubertal children with documented GH deficiency, of whom 86 were eligible for efficacy analysis. Participants received subcutaneous GHRH(1-29) (Sermorelin) at 30 μg/kg per day administered once daily at bedtime for up to 12 months, with linear growth, bone-age progression, and clinical chemistry monitored at 3–6 month intervals. Mean height velocity rose from 4.1 ± 0.9 cm/year at baseline to 8.0 ± 1.5 cm/year at 6 months and 7.2 ± 1.3 cm/year at 12 months, and 74% of children met the investigators' definition of a "good response" at the 6-month mark. The ratio of change in bone age to change in height age was not significantly different from unity (1.04 ± 0.58; P = 0.63), indicating proportionate skeletal maturation rather than disproportionate bone-age advancement. No adverse changes in fasting glucose, IGF-1 generation, or general biochemical and hormonal panels were observed, and the once-daily bedtime regimen was generally well tolerated.

Researchers gave a single nightly Sermorelin injection to over 100 children whose pituitaries were not making enough growth hormone on their own. Before the study, these children were growing about 4 cm per year. After 6 months of nightly Sermorelin, they were growing about 8 cm per year — close to doubling their growth rate. Importantly, their bones did not "age" faster than they grew taller, which matters because some growth interventions can cause the skeleton to mature too quickly. Blood sugar and other lab values stayed normal, and the injections were generally well tolerated.