Research Peptide Reference Table: CAS, Formula, Molecular Weight and Sequence

For laboratory research use only. Not for human or veterinary use.

When you're checking a Certificate of Analysis, planning a calculation or writing up a method, the first thing you usually need is the basic chemical identity of the compound. This page brings those identifiers together for every product in the Pepy shop in one table.

Every value below was checked against the compound's PubChem record. Where we couldn't find a single authoritative public record, or where public databases list more than one form, we've written see batch CoA rather than guess. The certificate for your batch on our lab results page is always the controlling document for the material in your vial.

How to use this table

• CAS number: a registry number assigned by the Chemical Abstracts Service. One compound can have several CAS numbers for different salt forms, so a mismatch isn't automatically an error.
• Molecular formula and MW: PubChem's computed values for the record listed. Molecular weight here is the average mass in g/mol. Mass spectrometry often reports monoisotopic mass, which is slightly lower for larger peptides.
• Sequence: three-letter amino acid codes, N-terminus to C-terminus. "Ac-" means an acetylated N-terminus, "-NH2" an amidated C-terminus, "Nle" norleucine and "D-Phe" the D-isomer of phenylalanine.
• PubChem: the compound ID (CID) we checked against. Click through to see synonyms, structure and computed properties.

Reference table

Notes on individual compounds

TB-500. "TB-500" is a trade name, not a systematic name. The values above are for the acetylated seven-residue fragment Ac-LKKTETQ (PubChem CID 62707662), not full-length thymosin beta-4, which is a 43-residue protein. Pepy supplies TB-500 only in the BPC-157 + TB-500 blend and the GLOW blend. Confirm against the batch CoA which material is present. See TB-500 vs BPC-157 for more on the distinction.

GHK-Cu. PubChem holds several records for copper GHK complexes, including a 1:1 complex and a 2:1 (bis) complex with different formulas, weights and CAS numbers. Free GHK (without copper) has its own record, CID 73587. Because these differ, we've left the CAS, formula and weight as "see batch CoA". The form tested on your certificate is the one that applies.

CJC-1295 without DAC. The best-known PubChem entry for "CJC-1295" (CID 91971820) describes the version with the drug affinity complex (DAC). That record doesn't describe the no-DAC peptide, and we didn't find an authoritative public record for the no-DAC form, so all values are "see batch CoA".

HGH (somatropin). Somatropin is a 191-amino-acid protein. PubChem's compound database isn't designed for proteins of this size, so there's no compound record to cite here. Sequence data for human growth hormone is held in protein databases such as UniProt (entry P01241).

Retatrutide. We didn't find a PubChem compound record for retatrutide by name or by its development code, so its values are "see batch CoA".

Tesamorelin. PubChem lists the formula and weight above, but its sequence isn't given in the record's synonyms, and more than one CAS number appears (probably for different salt forms). We've therefore shown sequence and CAS as "see batch CoA".

Melanotan 1. PubChem lists this compound as afamelanotide (CID 16197727).

Blends. A blend has no single formula or molecular weight. Use each component's row, and check the batch CoA for the stated amount of each component.

Why identifiers can differ between sources

You may notice small differences between this table, a supplier's label and a certificate:

1. Salt forms. Peptides are often supplied as acetate or trifluoroacetate (TFA) salts. The salt changes the formula weight of the solid but not the peptide itself.
2. Average vs monoisotopic mass. For a 5,000 Da peptide the difference is several daltons.
3. Rounding. Databases and labs round to different decimal places.
4. Different records. As with GHK-Cu, one common name can map to several database entries.

For concentration maths that depends on molecular weight, see our laboratory concentration and dilution calculations guide or the calculator.

Frequently asked questions

Why does my CoA show a different molecular weight? Usually because the lab reports monoisotopic mass, a salt form or different rounding. If the difference is large (more than a few daltons for a small peptide), compare the formula and sequence too, and contact us.

What does "see batch CoA" mean? It means we couldn't confirm a single public value we were willing to publish. The batch certificate is the reference for that compound.

Is PubChem the final authority? No. PubChem aggregates data from many depositors. It's a convenient, open cross-check, but the analytical data for your batch matters most.

Do you update this table? Yes, when we confirm a value against a certificate or authoritative record, we'll replace "see batch CoA" with that value and its source.

Sources

• PubChem compound records as linked in the table (National Center for Biotechnology Information): https://pubchem.ncbi.nlm.nih.gov/
• Free GHK, PubChem CID 73587: https://pubchem.ncbi.nlm.nih.gov/compound/73587
• CJC-1295 (with DAC), PubChem CID 91971820: https://pubchem.ncbi.nlm.nih.gov/compound/91971820
• UniProt P01241 (human somatotropin): https://www.uniprot.org/uniprotkb/P01241/entry

For laboratory research use only. Not for human or veterinary use.