Sermorelin

Sermorelin is the longest-studied GHRH analog: a peptide containing only the active 1-29 stretch of the hypothalamic releasing hormone, the exact segment that prompts the anterior pituitary to secrete GH. Everything that follows in the natural 44-residue molecule is left out.

Research findings:

• In 110 children with GH deficiency, a single evening dose each day lifted height velocity from 4.1 cm to 7.2 cm a year within twelve months (open-label multicenter study, 1996).
• In healthy older men, two subcutaneous doses per day for two weeks restored GH and IGF-1 dose-dependently to the levels seen in young men (1992).
• Six weeks of one nightly injection raised nocturnal GH output in eleven elderly men, while IGF-1, body composition and metabolic markers stayed where they were (1997).
• The BioDrugs review (1999) describes sermorelin as the shortest synthetic peptide that retains the complete activity of GHRH, and as a diagnostic probe of pituitary function.

The mechanism mirrors the natural hormone: binding to GHRH receptors on somatotroph cells, answered by pulses of GH. Because sermorelin carries none of the protective modifications that shield CJC-1295 or tesamorelin from DPP-IV breakdown, its half-life is only around 10 to 20 minutes. That makes it the fastest member of the family and the closest match to the body's brief, burst-like GHRH release. Researchers who want conditions as close to physiology as possible therefore tend to reach for this peptide rather than its longer-acting descendants.

Safety data come mostly from pediatric GH deficiency research and are consistently mild. What appears in studies and user reports:

• Local reactions where the needle went in: redness, pressure, brief irritation.
• Companions of raised GH such as fluid retention or tingling and numbness in the hands. Given the very short duration of action they tend to stay faint and resolve.
• A rise in fasting glucose and a temporary dip in insulin sensitivity are possible.
• Shortly after dosing, isolated reports mention facial flushing, headache or brief tiredness.
• Despite the extensive pediatric record, no robust studies cover use over long periods. In the 1997 trial body composition and metabolism were unchanged across six weeks, and nobody looked further than that.

This summary is no substitute for medical advice.

• Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency - review of mechanism, diagnostic use and growth data in children.
• Once daily subcutaneous growth hormone-releasing hormone therapy accelerates growth in growth hormone-deficient children during the first year of therapy - multicenter study in 110 children over twelve months.
• Effects of single nightly injections of growth hormone-releasing hormone (GHRH 1-29) in healthy elderly men - six weeks of single nightly doses in eleven elderly men.