BPC-157, TB-500, GHK-Cu, CJC-1295, Semax: peptide names look like they follow a system, but that system does not exist. Some names are literally the sequence, others are a programme code you can read nothing out of. This guide shows which information sits in a name — and which does not.
Peptide names come from two different worlds: systematic notation, where the letters are the amino acids (GHK = Gly-His-Lys), and programme codes like BPC-157, from which the sequence cannot be derived. Suffixes such as -NH2 and prefixes such as Ac- are genuine chemical information.
Systematic notation: the letters are the amino acids
In systematic notation each letter or abbreviation stands for one amino acid, and the reading direction is always from the N-terminus to the C-terminus. Two codes exist side by side: the three-letter code (Gly-His-Lys) and the one-letter code (GHK). Same chain, different spelling.
GHK-Cu is therefore a name you can unpack: glycine, histidine, lysine, plus a bound copper ion. For the bond between those amino acids, see what is a peptide bond; copper peptides in general are covered in copper peptides.
Programme codes: names that say nothing about structure
BPC-157, TB-500 and CJC-1295 are designators from a research programme: the letters point to the compound family or development track, the number is an internal code. Length, sequence and molecular weight cannot be traced from such a name — for that you need the specifications or the certificate of analysis.
Sometimes there is a clue. The TB in TB-500 points to Thymosin Beta, the protein family the fragment derives from; see what is TB-500. But that is a hint about origin, not a description of the molecule. Names like Semax and Selank were simply given by their developers.
Prefixes and suffixes that do mean something
Where the name itself can be arbitrary, the modifications at the ends are not: those are there as chemical information. A -NH2 at the end means an amidated C-terminus instead of a free carboxyl group. An Ac- at the front means an acetylated N-terminus. Both change how the molecule behaves, stability among other things.
A notation like (1-29) indicates a fragment: only amino acids 1 through 29 of the original protein. And where a D- appears before an amino acid, the mirror-image form has been used instead of the natural L-form — an intervention often intended precisely to slow degradation.
Why this matters in practice
Because two products with nearly the same name can be different molecules, and one molecule can circulate under several names. The only thing that fixes identity is the measured sequence or mass, not the label. So the molecular weight and sequence sit in the specifications on our product pages, and the measured value per batch on the certificate.
How that measurement works is in what is mass spectrometry; the purity side in what is HPLC. Searching by name, the A-Z peptide index is the quickest starting point.
This information is general and educational in nature. Peptide Lab supplies research peptides for laboratory and research purposes only. Not for human or animal consumption, not a medicine and not medical advice.
Frequently asked questions about peptide names
Why are peptides called things like BPC-157 or CJC-1295?
Those names are programme codes, not chemical descriptions. The letters point to the research programme or compound family the substance came out of; the number is an internal designator. You cannot derive the sequence from such a name.
What does GHK mean in GHK-Cu?
GHK are the one-letter codes of the three amino acids in the chain: glycine (G), histidine (H) and lysine (K). Cu is the symbol for copper, the ion bound to the tripeptide. Here the name really is the sequence.
What does -NH2 after a peptide name mean?
That the C-terminus is amidated instead of carrying a free carboxyl group. It is a chemical modification that affects the molecule's stability; Ac- at the front indicates an acetylated N-terminus in the same way.
When is something a peptide and when a protein?
The distinction is convention, not a law of nature. Chains up to roughly fifty amino acids are generally called peptides, longer ones polypeptides or proteins. The chemical bond between the amino acids is the same in both cases.
