This article is an identity reference comparing five compounds that are usually catalogued together — sermorelin, tesamorelin, CJC-1295, ipamorelin and hexarelin — by sequence, length, modification and mass. They fall into two structural classes that look nothing alike on paper or on a chromatogram. It makes no claim about what any of these compounds does and contains no preparation, handling or dosing guidance.
Two structural classes
The first class is built on the sequence of human growth hormone-releasing hormone (GHRH), a 44-residue peptide. These GHRH analogues are long chains of mostly standard amino acids: sermorelin is the first 29 residues, tesamorelin is all 44 with an N-terminal cap, and CJC-1295 is the 29-residue fragment with four substitutions.
The second class is the GHRP-type peptides, a separate family of short synthetic sequences. Ipamorelin and hexarelin are five and six residues long respectively, and each contains several residues that do not occur in proteins at all. They share no sequence with GHRH. The only thing the two classes have in common is the catalogue shelf they sit on.
The five compounds side by side
Each compound has its own identity reference on this site, linked in the first column. Masses are average molecular masses for the neutral molecule.
| Name | Class | Length | Key modifications | Approx. MW |
|---|---|---|---|---|
| Sermorelin | GHRH analogue | 29 | Native GHRH(1–29) sequence, no substitutions; C-terminal amide | 3358 g/mol |
| Tesamorelin | GHRH analogue | 44 | Full GHRH(1–44) sequence; trans-3-hexenoyl group on the N-terminal tyrosine; C-terminal amide | 5136 g/mol |
| CJC-1295 (no DAC) | GHRH analogue | 29 | D-Ala2, Gln8, Ala15, Leu27 substitutions; C-terminal amide | Slightly above sermorelin |
| CJC-1295 DAC | GHRH analogue | 29 + Lys30 | As above, plus a lysine at position 30 carrying a maleimidopropionyl group | 3647 g/mol |
| Ipamorelin | GHRP-type | 5 | Aib-His-D-2-Nal-D-Phe-Lys-NH2: Aib, D-2-naphthylalanine, D-Phe; C-terminal amide | 712 g/mol |
| Hexarelin | GHRP-type | 6 | His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2: D-2-methyl-tryptophan, D-Phe; C-terminal amide | 887 g/mol |
The CJC-1295 (no DAC) mass is described rather than quoted: the four substitutions leave it close to sermorelin’s mass and only slightly heavier, and the exact figure should be taken from the analysis for the material in hand.
How the classes differ analytically
Length and peak shape
At 29 to 44 residues, the GHRH analogues are large enough that column pore size matters. Wide-pore stationary phases generally serve them better than the narrow-pore columns used for small molecules, and their peaks are naturally broader than those of short peptides. Electrospray mass spectra show a series of multiply charged ions, so a certificate should report the deconvoluted neutral mass or state the charge state it read. The short GHRP-type peptides give compact peaks and simple spectra, usually dominated by one or two charge states.
Hydrophobicity
Length is not the whole story. Ipamorelin and hexarelin are short, but they are dense with aromatic and non-natural side chains — a naphthalene in ipamorelin, two indole rings and a phenyl ring in hexarelin — so they retain on a C18 column far more strongly than their size would suggest. The GHRH analogues carry many charged and polar residues spread along a long chain, and their retention reflects the balance of those with hydrophobic stretches such as the leucine-rich region near the C-terminus.
Non-natural residues and stereochemistry
Every GHRP-type compound here contains at least two D-residues, and both contain a residue with no counterpart in proteins. Stereochemistry is invisible to a mass measurement: a sample in which a D-residue has racemised has exactly the same mass as correct material, and only a chromatographic separation can show the difference. CJC-1295 has the same issue at a single position, D-Ala2. Sermorelin and tesamorelin contain only standard L-amino acids in their chains.
Methionine
Sermorelin and tesamorelin both contain a methionine at position 27, which is prone to oxidation and gives a +16 Da companion species. CJC-1295 carries leucine at that position, so the formula contains no sulfur and that oxidation product is not expected. An observed sulfur-containing mass for material sold as CJC-1295 is a sign that sermorelin and CJC-1295 have been confused.
Detection
All five contain aromatic residues — tyrosine and phenylalanine in the GHRH analogues, naphthylalanine, tryptophan derivatives and phenylalanine in the GHRP-type compounds — so all absorb near 280 nm. Purity is still normally read on the peptide bond at around 214 nm so that impurities without an aromatic residue are counted. The guide to reading an HPLC chromatogram explains why the wavelength changes the purity figure.
DAC as a chemical modification
“DAC” is shorthand for the extra moiety that distinguishes CJC-1295 DAC from CJC-1295 without it. Chemically it is a lysine added at position 30 whose side-chain amine is acylated with a maleimidopropionyl group. A maleimide is a reactive five-membered ring that readily adds thiols and can also open by hydrolysis; hydrolysed or thiol-adducted material is a distinct species with a different mass. For a buyer, the DAC modification means three concrete things: a higher molecular weight (about 3647 g/mol), a different retention time, and a different mass spectrum. A certificate for one form is not evidence about the other.
Counter-ion and content
All five are normally isolated as salts, typically acetate or trifluoroacetate. The GHRH analogues carry several basic residues and so several counter-ions per molecule; the short GHRP-type peptides carry fewer counter-ions but a larger share of their weighed mass is counter-ion. Either way, net peptide content has to be reported separately from purity, as covered in purity versus net peptide content.
How the GHRH and ghrelin-receptor peptides are supplied here
Each compound is supplied as a lyophilised powder in a sealed vial: Sermorelin 2mg, Tesamorelin 10mg, CJC-1295 5mg, CJC-1295 DAC 2mg, Ipamorelin 5mg and Hexarelin 2mg, all listed in the GHRH and ghrelin-receptor peptides category. Each is analysed by independent reverse-phase HPLC, with the result published for that product. Vial size and the published HPLC purity are listed on each product page. Vials carry no batch or lot numbers; each vial is matched to its published test by crimp and cap colour.
Frequently asked questions
Is CJC-1295 the same as sermorelin?
No. Both are 29 residues long, but CJC-1295 has four substitutions relative to sermorelin’s native sequence, and the DAC form adds a modified lysine at position 30.
Is tesamorelin a longer version of sermorelin?
Its chain is the full 44-residue GHRH sequence, of which sermorelin is the first 29 residues, and it also carries a trans-3-hexenoyl cap on the N-terminus that sermorelin lacks.
Why do ipamorelin and hexarelin retain so strongly for their size?
Because most of their residues are aromatic or otherwise hydrophobic, including non-natural residues such as D-2-naphthylalanine and D-2-methyl-tryptophan.
Can mass spectrometry confirm the D-residues?
No. D- and L-forms have identical masses. Stereochemistry has to be addressed chromatographically.
Research use only. All products supplied by Battle Born Peptides are laboratory reference materials for in-vitro research and analytical use by qualified professionals. They are not drugs, foods, dietary supplements, cosmetics or medical devices; they are not approved by the FDA or any other regulator for use in humans or animals; and they are not intended to diagnose, treat, cure, mitigate or prevent any disease, or to affect the structure or any function of the body of humans or animals. Nothing in this article is preparation, handling or dosing guidance. See our full research-use terms.