Peptide Molecular Weights

This table gathers the identity data from the reference section of each compound guide in the research hub: molecular formula, molecular weight and the matching PubChem record, 90 entries in all. Every formula and weight was checked against its PubChem record in October 2026, and the notes below the tables cover the few entries where PubChem draws a different form. Each compound name links to its guide, which gives aliases, structure, sources and handling.

How to read the table

• Molecular formula is written in Hill order: carbon, then hydrogen, then the other elements alphabetically. A trailing ⁺ or ⁻ marks a charged species.
• Molecular weight is the average molar mass in g/mol, computed from standard atomic weights. Mass spectrometry often reports the monoisotopic mass instead, which is lower: 1418.70 against 1419.55 for BPC-157.
• Salt forms. Figures are for the free compound unless a salt or hydrate is named. Synthetic peptides usually carry acetate or trifluoroacetate counterions, which add mass at each basic site; the peptide salts explainer works through how much.
• PubChem CID links open the compound record, with its synonyms, computed properties and the sources that deposited it.

Peptides and peptide analogs

Small molecules and other compounds

Compounds without a single formula

Some guides cover substances with no single molecular formula. Cerebrolysin is a mixture of free amino acids and peptides under 10 kDa. Thymalin is described in the literature as a thymus polypeptide complex. The mass of PEG-MGF depends on the PEG chain attached, and no PubChem record corresponds to the IGF-1 LR3 construct or to Adamax. Blends such as KLOW, Wolverine, CJC-1295 with ipamorelin and tesamorelin with ipamorelin appear in the tables under their components.

Notes on specific entries

• GHK-Cu. PubChem draws CID 71587328 as a singly charged cation, C₁₄H₂₃CuN₆O₄⁺ (402.92 g/mol). The table gives the neutral complex: the free GHK peptide (C₁₄H₂₄N₆O₄, 340.38 g/mol, CID 73587) less two protons plus one Cu(II) ion.
• VIP. Native VIP ends in a C-terminal amide, and CID 16140438 matches the amidated peptide. The records holding (CID 53314964) and aviptadil (CID 16132300) are drawn as the free acid, C₁₄₇H₂₃₇N₄₃O₄₃S (3326.8 g/mol).
• TB-500. Two rows link to the TB-500 guide: the acetylated fragment Ac-LKKTETQ, residues 17 to 23 of thymosin β4, and the full-length 43-residue protein. The guide explains which values describe which.
• 5-Amino-1MQ. Values are for the 5-amino-1-methylquinolinium cation, filed under its own record. The iodide salt is C₁₀H₁₁IN₂, 286.11 g/mol.
• AHK-Cu. The PubChem record (CID 168431292) is the monohydrochloride copper complex. The free AHK peptide is C₁₅H₂₆N₆O₄, 354.41 g/mol.

Converting milligrams to micromoles

Amount in moles is mass divided by molar mass. For any compound in the table, micromoles equal milligrams divided by the molecular weight, times 1,000. One milligram of BPC-157 (1419.55 g/mol) is 0.704 µmol, so dissolved to a final volume of 1 mL it gives a 704 µM (0.704 mM) solution. Peptide powders also hold counterions and water, so base the calculation on the net peptide content printed on the lot's certificate; the peptide reconstitution guide and What is a COA? show where to find it.

Frequently asked questions

What is the molecular weight of BPC-157?

1419.55 g/mol for the free peptide, C₆₂H₉₈N₁₆O₂₂ (PubChem CID 9941957). A salt form weighs more per molecule; the BPC-157 guide has the full reference data.

What is the molecular weight of TB-500?

The name TB-500 is used for Ac-LKKTETQ, an acetylated fragment of thymosin β4: C₃₈H₆₈N₁₀O₁₄, 889.0 g/mol. Full-length thymosin β4 is C₂₁₂H₃₅₀N₅₆O₇₈S, 4963 g/mol. The TB-500 guide covers both.

What is the molecular weight of GHK-Cu?

401.91 g/mol for the neutral copper complex, C₁₄H₂₂CuN₆O₄. The free GHK peptide is 340.38 g/mol.

Why do molecular weights differ between sources?

Most differences come from the form described: free compound or salt, anhydrous or hydrate, neutral or charged, amidated or free acid. Rounding, and average against monoisotopic mass, account for the rest.

How do you convert milligrams to micromoles?

Divide the mass in milligrams by the molecular weight in g/mol, then multiply by 1,000. One milligram of a 1,000 g/mol peptide is 1 µmol.

Related guides

• What is a COA?
• TFA vs acetate peptide salts
• Peptide reconstitution guide
• Peptide solubility
• Amino acid codes and residue masses
• Peptide molecular weight calculator
• Peptide modifications explained
• How research peptides are made
• What is a peptide?
• COA portal: published certificates, by lot
• Research hub

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