Sermorelin vs CJC-1295.
Sermorelin and CJC-1295 start from the same 29 amino acids of growth hormone-releasing hormone. CJC-1295 changes four of them to resist enzymatic cleavage, and its DAC form adds an albumin-binding anchor that stretches its half-life from minutes to days. Here is the comparison, residue by residue.
One backbone, three molecules.
| Sermorelin | CJC-1295, no DAC | CJC-1295 with DAC | |
|---|---|---|---|
| What it is | GHRH(1-29) amide | GHRH(1-29) amide with four substitutions, also called modified GRF (1-29) | Modified GRF (1-29) plus a C-terminal lysine carrying a maleimidopropionamide group |
| Length | 29 amino acids | 29 amino acids | 30 amino acids |
| Formula | C149H246N44O42S | C152H252N44O42 | C165H269N47O46 |
| Molecular weight | 3357.9 g/mol | 3367.9 g/mol | 3647.2 g/mol |
| Binds albumin | No | No | Yes, covalently |
| Half-life | Minutes in plasma | Short; no albumin anchor | 5.8 to 8.1 days in healthy adults |
| Receptor | GHRH receptor | GHRH receptor | GHRH receptor |
Formulas and weights for the 29-residue peptides from Helion's peptide molecular weight calculator, matching PubChem; the DAC form from PubChem.
Residue by residue.
Sermorelin
YADAIFTNSYRKVLGQLSARKLLQDIMSR‑NH2
CJC-1295 (no DAC)
YaDAIFTQSYRKVLAQLSARKLLQDILSR‑NH2
Lowercase a is D-alanine. The four changed positions are underlined.
| Position | Sermorelin | CJC-1295 | Why it matters |
|---|---|---|---|
| 2 | Ala | D-Ala | Plasma DPP-IV cuts GHRH between residues 2 and 3; a D-amino acid at position 2 blocks that cut |
| 8 | Asn | Gln | Asparagine 8 deamidates in water, and in one GRF analog study it drove most of the degradation |
| 15 | Gly | Ala | One of the four substitutions that define modified GRF (1-29) |
| 27 | Met | Leu | Methionine is among the residues most open to oxidation; leucine is not |
Why the changes were made.
Sermorelin is GHRH(1-29), described in a 1999 review as the shortest synthetic peptide with the full biological activity of GHRH. Its weakness is plasma. A 1989 study showed that the main enzyme cutting GHRH in plasma is dipeptidyl peptidase-IV, which removes the first two residues; GHRH(1-29) was cleaved rapidly, and a D-amino acid at position 1 or 2 prevented the cut. A GRF(1-29) analog incubated in animal plasma had a half-life of 8 to 22 minutes in vitro.
CJC-1295 answers each weak point: D-alanine at position 2 against DPP-IV, glutamine in place of the deamidation-prone asparagine 8, and leucine in place of the oxidation-prone methionine 27, plus alanine at 15. The guide to how long peptides last covers deamidation and oxidation in water.
The albumin anchor.
The 2005 paper that identified CJC-1295 attached a maleimidopropionamide-modified lysine to the C-terminus of the tetrasubstituted peptide. That group bonds to the free thiol on cysteine 34 of serum albumin, and the peptide was still present in rat plasma beyond 72 hours. In healthy adults, a clinical study estimated the half-life of CJC-1295 with DAC at 5.8 to 8.1 days. Most published CJC-1295 data describe that DAC form; the CJC-1295 DAC vs no DAC guide covers the difference.
CJC-1295 no DAC, in the CP10 blend.
Helion supplies CJC-1295 without DAC, 5mg, blended with 5mg of ipamorelin in CJC-1295 + Ipamorelin 10mg (CP10). Lot 335XA tested at 99.85% HPLC purity at ILS Laboratories, and the report is in the COA Portal. Helion does not sell sermorelin. For the wider family, see tesamorelin vs sermorelin vs ipamorelin.
Specs and storage by compound.
Questions (6)
What is the difference between sermorelin and CJC-1295?
Sermorelin is GHRH(1-29), the first 29 amino acids of growth hormone-releasing hormone. CJC-1295 is the same 29 residues with four substitutions (D-Ala2, Gln8, Ala15, Leu27) that resist enzymatic cleavage; its DAC form adds an albumin-binding lysine that extends its half-life to days.
Is CJC-1295 the same as sermorelin?
No. They share a backbone, but CJC-1295 changes four residues, so it is a different molecule with a different molecular weight: 3367.9 g/mol without DAC against 3357.9 for sermorelin.
What is modified GRF (1-29)?
Another name for CJC-1295 without DAC: GRF(1-29) amide with the four substitutions D-Ala2, Gln8, Ala15 and Leu27.
Which lasts longer, sermorelin or CJC-1295?
CJC-1295 with DAC, by far: about 5.8 to 8.1 days in healthy adults, because it binds albumin. Sermorelin is cut by plasma DPP-IV within minutes, and CJC-1295 without DAC has no albumin anchor.
What does DAC mean in CJC-1295?
Drug affinity complex: a lysine carrying a maleimidopropionamide group, added at the C-terminus, that bonds to serum albumin.
Does Helion sell sermorelin?
No. Helion supplies CJC-1295 without DAC, blended with ipamorelin (CP10), for laboratory research use only.
Published studies (6)
- Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency
- Dipeptidylpeptidase IV and trypsin-like enzymatic degradation of human growth hormone-releasing hormone in plasma
- In vitro metabolic degradation of a bovine growth hormone-releasing factor analog Leu27-bGRF(1-29)NH2 in bovine and porcine plasma. Correlation with plasma dipeptidylpeptidase activity
- Degradation of growth hormone releasing factor analogs in neutral aqueous solution is related to deamidation of asparagine residues. Replacement of asparagine residues by serine stabilizes
- Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats: identification of CJC-1295 as a long-lasting GRF analog
- Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults
Citations from PubMed for reference. They describe the compound in the literature, not any Helion lot, and nothing here is guidance on use.