What Is Sermorelin? GRF (1-29) Structure and History

Sermorelin is GRF (1-29) amide, the first 29 amino acids of human growth hormone-releasing hormone with an amide at the C-terminus. Its sequence is YADAIFTNSYRKVLGQLSARKLLQDIMSR-NH2, its formula C149H246N44O42S, its molecular weight about 3357.9 Da and its CAS number 86168-78-7 [1]. Native growth hormone-releasing hormone has 44 residues; the 29-residue fragment was found to retain the activity of the full hormone in early studies.

What is its history?

Sermorelin was developed and marketed in the United States as a prescription product and was later discontinued by its manufacturer. It is the parent sequence of several research analogs, including the tetrasubstituted peptide sold as CJC-1295 without DAC and the albumin-binding CJC-1295 with DAC, whose published pharmacology appeared in 2006 [2].

What are its stability weak points?

Three features of the sequence limit its lifetime. The alanine at position 2 lets dipeptidyl peptidase-4 cut off the first two residues, which inactivates the peptide. The asparagine at position 8 can deamidate. The methionine at position 27 oxidizes, adding 16 Da. Later analogs replaced exactly these residues.

What should a lab report show?

Identity by mass spectrometry, where the peptide appears as multiply charged ions deconvoluted to about 3357.9 Da, and purity by HPLC. Peaks at plus 16 Da indicate oxidation at methionine 27, and peaks at plus 1 Da can indicate deamidation. Because those impurities sit close to the main peak, the chromatogram matters as much as the purity number.

Frequently asked questions

Is sermorelin the same as CJC-1295?

No. CJC-1295 without DAC differs from sermorelin at four positions and weighs about 3367.9 Da; CJC-1295 with DAC is larger still.

What does GRF stand for?

Growth hormone-releasing factor, an older name for growth hormone-releasing hormone.

Does FLASK list sermorelin?

Yes, as Sermorelin 5 mg, with sequence, formula and CAS number on the product page.