How Peptides Are Named: Decoding BPC-157, GHK, and TB-500

If you have ever wondered how peptides are named, the labels can look like a random scramble of letters and numbers — BPC-157, GHK, TB-500, GEPPPGKPADDAGLV. They are not random. Each name follows one of a handful of conventions, and once you know the systems, a peptide’s name starts to tell you something about what it is. This post breaks down how peptides are named, the amino acid codes those names are built from, and why a single peptide can carry several different names at once.

There is no single peptide naming system

The first thing to understand about how peptides are named is that there isn’t one official system — there are several, used side by side. A given peptide might be known by a functional nickname, a string of letters that spells out its sequence, a laboratory catalog code, and a formal systematic name, all at the same time. That is why the naming looks inconsistent: you are seeing several conventions layered on top of each other. The four you will run into most often are covered below.

The amino acid alphabet: the codes behind every name

Most peptide names are built, directly or indirectly, on the twenty standard amino acids — and each amino acid has two standardized abbreviations: a three-letter code and a one-letter code, set by the IUPAC-IUB nomenclature commission IUPAC-IUB amino acid symbols → https://iupac.qmul.ac.uk/AminoAcid/A2021.html.

• Alanine — Ala — A
• Arginine — Arg — R
• Asparagine — Asn — N
• Aspartic acid — Asp — D
• Cysteine — Cys — C
• Glutamic acid — Glu — E
• Glutamine — Gln — Q
• Glycine — Gly — G
• Histidine — His — H
• Isoleucine — Ile — I
• Leucine — Leu — L
• Lysine — Lys — K
• Methionine — Met — M
• Phenylalanine — Phe — F
• Proline — Pro — P
• Serine — Ser — S
• Threonine — Thr — T
• Tryptophan — Trp — W
• Tyrosine — Tyr — Y
• Valine — Val — V

A few extra symbols appear in partially determined sequences: B means aspartate or asparagine when the two have not been distinguished, Z means glutamate or glutamine, and X means an undetermined or atypical residue. By convention, sequences are written from the N-terminus to the C-terminus (left to right), and in one-letter notation an uppercase letter denotes the standard L-form of the amino acid.

The four main ways peptides get their names

1. Sequence-based names (the letters are the molecule). The most literal naming style spells the peptide out in its amino acid codes. GHK is the clearest example: the name is simply the one-letter codes for its three residues — Gly-His-Lys (glycine–histidine–lysine). Read the name and you have read the sequence. When such a peptide forms a complex, a suffix is added: GHK-Cu denotes the GHK tripeptide bound to copper. Longer strings work the same way — BPC-157’s full sequence, GEPPPGKPADDAGLV, is just its fifteen one-letter codes read N-to-C.

2. Descriptive or functional abbreviations. Some names are abbreviations of a descriptive phrase, usually followed by a laboratory number. BPC-157 is a good example: “BPC” stands for Body Protection Compound, the name of a series of peptide fractions studied by researchers at the University of Zagreb, and the “157” identifies this specific pentadecapeptide as the 157th candidate from that screening program. The number is a lab designation — not a measurement, a strength, or a dose. That is worth remembering, because the digits in a peptide name rarely mean what people assume they mean.

3. Parent-molecule and fragment designations. Many peptides are fragments of a larger protein, and their names point back to the parent. TB-500 is a synthetic peptide (acetyl-LKKTETQ) corresponding to a short active region — residues 17 to 23 — of thymosin beta-4, a 43-amino-acid protein; “TB” stands for Thymosin Beta. Here is the catch, and a useful lesson in reading names critically: “TB-500” is a research-and-vendor naming convention, not an official biochemical designation. No IUPAC or pharmacopeial standard defines exactly what “TB-500” is, which is part of why products sold under that name can differ. (Its formal international nonproprietary name is fequesetide — a name almost nobody uses outside regulatory documents.) A name can be in wide use and still be unofficial.

4. Systematic and formal names. Finally, every peptide has formal identifiers that do not depend on nicknames at all: a full systematic (IUPAC) chemical name, a CAS Registry Number, and database identifiers such as a PubChem CID. These are the unambiguous handles that labs and regulators rely on. They are unwieldy for everyday conversation — which is exactly why the shorter nicknames exist — but they are the names that pin a compound down precisely.

Why one peptide can have several names

A single peptide routinely carries a common or trade name, a lab code, a sequence string, a formal INN, and a CAS number — all valid, all pointing to the same molecule. That is manageable once you know they are synonyms, and genuinely confusing if you don’t. It is also why the identity line on a Certificate of Analysis matters: a CoA ties the name on the label back to the measured sequence and mass, so you can confirm the material actually is what the name claims. This is the whole thrust of our “Reading the Report” series — see how a CoA establishes identity How to Read a Peptide Certificate of Analysis → https://apexpeptidesupply.com/how-to-read-peptide-certificate-of-analysis/ and how mass spectrometry confirms it against the theoretical sequence (((placeholder → What peptide mass spectrometry confirms →https://apexpeptidesupply.com/peptide-mass-spectrometry/ . You can view worked examples on our published certificates (((placeholder → third-party Certificates of Analysis →https://apexpeptidesupply.com/wp-content/uploads/2026/07/APS26-0144-BPC-15710MG-1.pdf

How to decode an unfamiliar peptide name

• Check whether the letters are amino acid codes. If the name is a short run of letters that map to the one-letter alphabet (like GHK), it may be the sequence itself.
• Separate the letters from the number. The letters are usually an abbreviation — a functional phrase or a parent molecule — while the number is usually a lab or catalog designation, not a strength or purity value.
• Look for a parent protein. A prefix like “TB” (thymosin beta), or a stated residue range, signals the peptide is a fragment of something larger.
• Find the formal identifier. For anything that has to be precise, track down the CAS number or a database ID — that is the name that cannot be confused with another compound.
• Confirm against a CoA. A name only matters if the material matches it, and identity testing is what connects the two.

Frequently asked questions

What do the numbers in peptide names mean?
Usually a laboratory or catalog designation. For example, the “157” in BPC-157 marks it as the 157th candidate in a screening series. The numbers are generally not doses, concentrations, or purity values.

What does GHK stand for?
GHK is a sequence-based name: the one-letter amino acid codes for glycine (G), histidine (H), and lysine (K). The name literally spells the tripeptide’s sequence. In its copper-bound form it is written GHK-Cu.

Why is one peptide called by several different names?
Peptides accumulate names from different systems — a descriptive nickname, a lab code, a sequence string, a formal INN, and a CAS number can all refer to the same molecule. A Certificate of Analysis ties the name back to the measured identity.

Are peptide names standardized?
Only partly. The amino acid codes are standardized by IUPAC-IUB, and formal systematic names and CAS numbers are unambiguous. But many common names (such as TB-500) are vendor or research conventions with no official standard, which is why usage varies.

Research-use-only notice

All products supplied by Apex Peptide Supply are sold strictly for laboratory research use only (RUO). They are not drugs, foods, cosmetics, or medical devices, and are not intended for human or veterinary use, consumption, diagnosis, treatment, or the prevention of any disease. Any compounds named in this article are referenced solely as examples of naming conventions and molecular structure; nothing here should be read as describing or implying any biological, clinical, or therapeutic effect. All work with research compounds must be performed by qualified individuals in an appropriate setting, in accordance with all applicable laws and institutional requirements.