Sermorelin vs Tesamorelin vs CJC-1295 (No DAC): Analyst’s Comparison

Sermorelin, tesamorelin and CJC-1295 (no DAC) all act at the GHRH receptor, but they are three different molecules: sermorelin is native GHRH(1-29) amide, tesamorelin is the full 44-residue GHRH(1-44) carrying a trans-3-hexenoyl group on its N-terminus, and CJC-1295 without DAC is GRF(1-29) with four substitutions (D-Ala2, Gln8, Ala15, Leu27). On a certificate, tesamorelin stands out at 5135.8 g/mol, while CJC-1295 (about 3367.9) and sermorelin (3357.9) are only 10 g/mol apart, so the mass reading deserves a close look.

This comparison is written from the analyst’s chair. It starts with sequence and mass, explains where the differences come from, lists what a certificate should report for each analog, and only then moves to vial choice and the cost per milligram. The narrative background sits in dedicated articles, linked where they apply.

How do the three sequences line up?

Sermorelin is the yardstick: the shortest fully active stretch of GHRH, without modification. The sermorelin reference-analog article explains why it serves that role, and tesamorelin as a stabilised GHRH analog covers the longer molecule.

Where does the 10 g/mol gap between sermorelin and CJC-1295 come from?

The four substitutions in CJC-1295 add up to a small, predictable shift:

• Ala2 to D-Ala2: same atoms, so 0 g/mol. The published rationale is resistance to dipeptidyl peptidase-4 cleavage between residues 2 and 3.
• Asn8 to Gln8: one extra CH2, +14.03. Glutamine is less prone than asparagine to deamidation through a succinimide intermediate.
• Gly15 to Ala15: +14.03. Alanine favours the helical conformation in that region.
• Met27 to Leu27: −18.03. Leucine removes an easily oxidised sulfur.

Net change: +10.03 g/mol, which takes 3357.9 to roughly 3367.9. Tesamorelin keeps the native sequence and instead blocks the N-terminus with a hexenoyl group (C6H8O added, about 96.1 g/mol); remove it and the calculated mass falls to about 5039.7, the value for unmodified GHRH(1-44) amide. The design logic behind these changes is covered in peptide half-life and analog modifications and, for the DAC question, CJC-1295 with DAC vs without DAC.

What should a certificate report for each analog?

Larger peptides usually appear in electrospray spectra as multiply charged ions. Approximate average-mass values:

Points an analyst checks beyond the headline mass:

• Sermorelin vs CJC-1295: at the 4+ charge state the two differ by only about 2.5 m/z, so the deconvoluted mass matters more than a single peak label.
• Oxidation: sermorelin and tesamorelin both carry Met27, so a +16 companion peak signals methionine sulfoxide. CJC-1295 has no methionine and should not show it.
• Stereochemistry: D-Ala2 is invisible to mass spectrometry. Chromatographic separation of the diastereomer or the synthesis record carries that evidence.
• Acyl group: a tesamorelin peak about 96 g/mol light would indicate material lacking the hexenoyl cap.

ExoLabz products are third-party tested by HPLC with purity testing and are 99%+ purity. Certificates are published for some products on the COAs page, and every vial is matched to its certificate by cap and crimp colour. How to read a peptide certificate of analysis walks through each field.

What do the three do at receptor level?

All three are agonists at the GHRH receptor, a class B G-protein-coupled receptor that signals through Gs and cAMP. In-vitro literature measures cAMP accumulation in receptor-expressing cell lines and hormone release from pituitary cell preparations, and compares how quickly each analog is cleaved when incubated with plasma or purified peptidases. The differences between them sit mainly in that enzymatic stability, not in which receptor they engage. For how this receptor class differs from the ghrelin-receptor compounds, see GHRH analogs vs growth hormone secretagogues.

Where does the CJC-1295 + Ipamorelin blend fit?

The CJC-1295 & Ipamorelin blend 10mg (5+5) is a different kind of pairing. It combines a GHRH-receptor agonist with ipamorelin, which acts at GHS-R1a, so it suits in-vitro questions about two receptor classes in the same system rather than a comparison of GHRH analogs. Its composition is analysed in the CJC-1295 & Ipamorelin blend article, and ipamorelin’s receptor profile in ipamorelin GHS-R1a selectivity.

Which vial answers which lab question?

• Setting up a receptor assay or an HPLC method: Sermorelin 5mg as the unmodified reference agonist.
• Running the reference arm across a full plate series: Sermorelin 10mg, at a much lower cost per milligram.
• Testing how substitutions change stability against the reference: CJC-1295 (no DAC) 5mg alongside sermorelin.
• Working with the full-length, acylated sequence: Tesamorelin 10mg, currently out of stock, so plan the run around restock.

What does a milligram, and a micromole, cost?

Prices in CAD. Quantity pricing reaches up to 25% off at 10+ vials in the cart; the “25% off” column applies that full rate. Because these molecules range from about 3,358 to 5,136 g/mol, cost per micromole gives a fairer like-for-like figure.

Orders ship from inside Canada, go out within one business day, and travel with free tracking above $200 CAD. The Sermorelin Canada page and the Canadian price list carry the rest of the catalogue.

Frequently asked questions

Is CJC-1295 without DAC the same as modified GRF(1-29)?

Yes. Both names describe GRF(1-29) amide with D-Ala2, Gln8, Ala15 and Leu27, about 3367.9 g/mol and 29 residues.

Why is tesamorelin so much heavier than the other two?

It carries all 44 residues of GHRH instead of the first 29, plus the hexenoyl group, which brings it to 5135.8 g/mol.

Can a mass spectrum tell sermorelin and CJC-1295 apart?

Yes, but narrowly. The 10 g/mol difference is clear after deconvolution, whereas a low-resolution single-ion reading can blur it.

Does the CJC-1295 sold here contain DAC?

No. The ExoLabz vial is the no-DAC form, with no lysine-linked maleimide linker attached.

Why would a sermorelin certificate show a peak 16 higher?

That is typically methionine oxidation at position 27, which is one reason CJC-1295 replaces Met27 with leucine.

Which analog makes the most sensible reference standard?

Sermorelin, because it is the unmodified 1-29 sequence. Each change in CJC-1295 or tesamorelin can then be read as a departure from that baseline instead of from another engineered analog.

Sermorelin, tesamorelin and CJC-1295 are sold by ExoLabz only for in-vitro laboratory research and are not for human or veterinary use.