Epithalon: four residues, five certificates

After GHK-Cu, Epithalon is the smallest molecule in this catalogue. Four amino acids, nothing more, and that is exactly why it shows so clearly what a certificate of analysis can and cannot do.

Ala-Glu-Asp-Gly, nothing more

The sequence is Ala-Glu-Asp-Gly, AEDG in one-letter code. Four amino acids, molecular formula C₁₄H₂₂N₄O₉, molar mass 390.35 g/mol, CAS number 307297-39-8. All of it is on the product page.

Two of the four residues, glutamic acid and aspartic acid, each carry an additional acid group. A molecule this short and this acidic dissolves readily in water, which is the practical side of this observation.

The same substance is also listed under the name Epitalon. Both spellings refer to the same molecule with the same CAS number; when checking a certificate, match the number, not the spelling.

Five certificates from two vial sizes

The certificate library holds five certificates of analysis for this substance. Three come from 10 mg lots and two from 5 mg lots, so from two different fill sizes; the vial sold here is 10 mg.

That is normal for a substance that has been filled in different sizes over a longer period, not a contradiction. A certificate belongs to the lot it comes from. It claims nothing more, and nothing more should be read into it.

Five certificates, all with a figure

All five report a measured purity: above 99.8%, 98.8%, 98.93%, 98.35% and 98.327%. Each figure appears exactly like this in the certificate for the respective lot.

The two lowest figures, 98.327% and 98.35%, are both above 98%. What to look for in a certificate is explained in How to read a certificate of analysis.

Why four residues reach such high values

Four amino acids mean three coupling steps in solid-phase synthesis. With so few steps there is little opportunity for incomplete chains, and the values are correspondingly high. That is not to any supplier's credit, it is simply the chain length: for Retatrutide with 39 residues the same figure is far harder to reach.

The flip side of short chains is their vulnerability: a molecule with few residues is quickly broken down by enzymes. That is why many of the short regulatory peptides in this catalogue carry a stabilising addition. Epithalon does not; it is the unmodified sequence.

Before preparing a solution

The product is supplied as a lyophilised powder. It goes into solution with bacteriostatic water; the concentration follows from the mass in the vial and the volume added, as described under reconstitution. With a molecule this light it is worth looking at the peptide content: at 390 g/mol, salts and residual moisture weigh more heavily than in a long chain.

In brief

Four amino acids, 390.35 g/mol, CAS 307297-39-8, five certificates of analysis from two vial sizes, all with a figure.

Questions

Are Epithalon and Epitalon the same?

Yes. Both spellings refer to the same substance with CAS number 307297-39-8. When checking a certificate, the number counts, not the spelling.

Why do the certificates come from two different vial sizes?

Because the substance has been filled in 10 mg and 5 mg lots over a longer period. Each certificate applies to its own lot; the vial sold here is 10 mg.

Do all certificates give a percentage?

Yes. All five give a measured purity, from 98.327% to above 99.8%, and all are in the library, including the lower values.