Quick answer: Sermorelin is the natural 29-residue GHRH fragment. CJC-1295 without DAC is the same core with four substitutions meant to slow breakdown, and CJC-1295 with DAC adds an albumin-binding linker. They differ in mass and stability, so a certificate should confirm which one was supplied. All materials are for laboratory research use only.
Two growth hormone-releasing hormone analogs, one family
Sermorelin and CJC-1295 belong to the same peptide family. Both are analogs of growth hormone-releasing hormone (GHRH), the hypothalamic peptide that acts on the GHRH receptor on pituitary cells. In preclinical work they are used as tools for studying that receptor pathway. Because they share a target, they are often compared, and because their names appear side by side in supplier catalogs, they are often confused.
This guide compares them on structure, stability, what the literature reports about duration, what a certificate should show, and which questions matter when choosing between them. Everything here is for laboratory research use only, and nothing describes a benefit. For the single-compound background see the sermorelin research overview and the CJC-1295 (no-DAC) research overview.
Structure: the 29-residue core they share
Native GHRH has 44 amino acids, but the first 29 residues carry the receptor-activating function. Sermorelin is that 29-residue fragment, GRF(1-29), with an amidated C-terminus. It keeps the natural sequence unchanged, which is part of why it is a common reference material.
The CJC-1295 name is used for two different products, and this is the first thing to pin down. “CJC-1295 without DAC,” also written modified GRF(1-29), uses the same 29-residue core but swaps four amino acids at positions chosen to slow enzymatic cleavage. “CJC-1295 with DAC” adds a drug affinity complex, a reactive linker that lets the peptide bind serum albumin. The no-DAC form is the one most comparable to sermorelin, and it is what V8 lists as the CJC-1295 (no-DAC). Our DAC vs no-DAC comparison covers the split in detail, and V8 also sells sermorelin.
Side-by-side comparison
| Point | Sermorelin | CJC-1295 (no-DAC / modified GRF 1-29) | CJC-1295 with DAC |
|---|---|---|---|
| Core | GRF(1-29), natural sequence | GRF(1-29) with four substitutions | Modified core plus albumin-binding linker |
| Length | 29 residues | 29 residues | 29 residues plus linker |
| Reported plasma stability | Minutes | Longer than sermorelin in assays | Days in published human data |
| Mass check | Reference value | Differs slightly, calculable | Differs substantially |
| Albumin binding | No | No | Yes |
| V8 listing | Sermorelin | CJC-1295 (no-DAC) | Not sold |
Stability and duration in the published work
Unmodified GHRH fragments are cleaved quickly in plasma. Early work showed the natural 1-44 peptide is inactivated by an enzyme that removes the N-terminal dipeptide, and sermorelin, having the natural N-terminus, shares that vulnerability. Its half-life in the studies is measured in minutes. The substitutions in modified GRF(1-29) were designed to blunt that cleavage, so the modified form persists longer in the same kind of assay.
The DAC variant goes further by binding albumin, and the clinical-pharmacology paper on it reported a half-life measured in days rather than minutes. Those figures describe published human studies of the compounds, not products sold for research, and V8 draws no conclusion from them. They explain why the three materials are not interchangeable in an experimental design that depends on exposure time.
Analytical differences a certificate should reflect
Because the modified peptide differs from sermorelin at four positions, its theoretical mass differs from sermorelin's by a small, exactly calculable amount. A certificate that reports a measured mass lets a buyer confirm which of the two was supplied; a certificate that only reports a purity percentage cannot. This is one reason to read the document beyond the headline number, as covered in how to read a COA.
Both peptides are 29 residues, so typical impurity classes are similar: deletion sequences, oxidized methionine or its equivalent, and deamidated forms. The modified peptide replaces a methionine, which removes one common oxidation route. Read the chromatogram for shoulders or a second peak close to the main one. Our HPLC purity guide and the compound-level pages sermorelin purity testing and CJC-1295 (no-DAC) purity testing go further.
Choosing between them for a research design
If an experiment needs the natural sequence as a reference, or compares against older literature that used sermorelin, sermorelin is the straightforward choice. If the design needs a longer-lived analog without the albumin-binding addition, the no-DAC modified form is the usual fit. If the design depends on prolonged exposure, the DAC form is a different material again and is not interchangeable with either.
Whichever you choose, write the exact compound into the protocol, including whether it is modified GRF(1-29), and record the lot. Mixing up the three is a documentation error that is easy to make and hard to find afterward. A related comparison between sermorelin and a different class of secretagogue is in sermorelin vs ipamorelin, and CJC-1295 vs ipamorelin covers the other pairing.
Sourcing and handling notes
Both come as lyophilized powder. The general handling rules are the same: keep sealed material cold, dry and protected from light, avoid repeated temperature cycling, and note the date a vial is opened. Because both are relatively short peptides, they are sensitive to the contamination and moisture risks that apply to any reconstituted material.
When comparing sellers, look for a named laboratory, a test date, a lot reference matching the vial, and the stated amount on the label. The supplier checklist and the buying pages where to buy sermorelin and where to buy CJC-1295 (no-DAC) apply these checks to each product.
Frequently asked questions
Is CJC-1295 the same as sermorelin?
No. Both are 29-residue GHRH analogs, but CJC-1295 without DAC has four amino acid substitutions and CJC-1295 with DAC adds an albumin-binding linker.
What does DAC stand for?
Drug affinity complex, a reactive group that lets the peptide bind serum albumin and persist longer in published studies.
Which form does V8 sell?
V8 lists sermorelin and CJC-1295 without DAC. It does not list the DAC form.
Why is sermorelin short-lived in the studies?
The natural N-terminus is cleaved quickly by a plasma enzyme, so reported half-life is measured in minutes.
What do the four substitutions do?
They were designed to slow enzymatic cleavage and, at one position, to remove a methionine that is prone to oxidation.
Can a purity percentage tell the two apart?
No. Identity needs a sequence or mass confirmation. The two differ in mass by a small but exact amount.
Are they interchangeable in a research design?
Not when exposure time matters. Name the exact compound in the protocol and record the lot.
Is the human half-life data a claim about V8 products?
No. It comes from published studies of the compounds and is background only.
How should I store either one?
Keep sealed lyophilized material cold, dry and away from light, and note the date a vial is opened.
Is either approved for any use?
Not as sold here. V8 Peptides sells them for laboratory research use only, not for human or animal consumption.
References
- Frohman LA, Downs TR, Williams TC, Heimer EP, Pan YC, Felix AM. Rapid enzymatic degradation of growth hormone-releasing hormone by plasma in vitro and in vivo to a biologically inactive product cleaved at the NH2 terminus. J Clin Invest. 1986;78(4):906-913.
- Teichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Frohman LA. 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. J Clin Endocrinol Metab. 2006;91(3):799-805.
- Ionescu M, Frohman LA. Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog. J Clin Endocrinol Metab. 2006;91(12):4792-4797.
- Walker RF. Sermorelin: a better approach to management of adult-onset growth hormone insufficiency? Clin Interv Aging. 2006;1(4):307-308.