What Are Research Peptides? A Documentation-First Overview
Published 2026-10-09 · Last updated: 2026-10-09 · By: Index Peptides technical team
Research peptides are synthetic peptides, short chains of amino acids joined by peptide bonds, made by chemical synthesis and supplied as laboratory reagents for in-vitro research. Each one is defined by its amino-acid sequence, CAS registry number, molecular formula and expected molecular weight, and each batch is documented on a certificate of analysis (COA). In the UK they are supplied as research use only (RUO) materials, not for human or animal use. This page explains what the term covers, how a research peptide is identified, and the documentation that stands behind a batch.
Research use only. Not for human or animal consumption.
Definition
A peptide is a chain of amino acids linked by peptide (amide) bonds. Chains of a few up to roughly fifty amino acids are usually called peptides; longer chains are generally described as proteins. The order of the amino acids, the sequence, is what makes one peptide a different compound from another.
A research peptide is a peptide supplied as a laboratory reagent. In practice the term describes four things:
- Synthetic material. Research peptides are made by chemical synthesis, most commonly solid-phase peptide synthesis, rather than extracted from biological sources.
- A defined identity. Each compound has a sequence, a CAS registry number, a molecular formula and an expected molecular weight.
- A dry, stable form. Most are supplied as a lyophilised (freeze-dried) powder in a sealed vial, the most stable form for storage and transport.
- Batch documentation. Each batch carries its own certificate of analysis reporting what that lot measured.
Research catalogues often also list related non-peptide materials, such as the coenzyme NAD+. These are documented in the same way but are not peptides.
Identity is defined by chemistry, not by the name
Product names are a poor guide to identity. Similar names can describe chemically distinct compounds, and one name can be used for more than one species. The identity reference is the sequence, CAS number, molecular formula and expected mass. Four common examples, with their sequence, CAS number and free-form reference molecular weight:
| Name as listed | What it denotes | CAS | Reference MW (free form) |
|---|---|---|---|
| BPC-157 | 15-residue peptide GEPPPGKPADDAGLV | 137525-51-0 | 1419.6 g/mol |
| KPV | Tripeptide Lys-Pro-Val | 67727-97-3 | 342.4 g/mol |
| TB-500 | Heptapeptide Ac-LKKTETQ (thymosin beta-4 residues 17-23) | 885340-08-9 | 889.0 g/mol |
| GHK-Cu | Gly-His-Lys copper complex | 89030-95-5 | 401.9 g/mol |
Two examples show why this matters. Material sold as TB-500 is almost always the short Ac-LKKTETQ fragment, not full-length thymosin beta-4 (CAS 77591-33-4, roughly 4,963 g/mol), which is a far larger molecule. And the free GHK tripeptide without copper (CAS 49557-75-7) is a different compound from GHK-Cu. Similar names, different chemistry.
Form adds a second layer. Supplied material is often a salt, commonly acetate or TFA, with a higher as-weighed mass than the free-form reference values above. The batch COA is authoritative for the form that was actually tested. The BPC-157 compound page shows how these identity fields are set out for a single compound.
What "research use only" means
RUO is a supply category. Material in it is supplied for in-vitro laboratory research, to qualified researchers and laboratories, and is not for human or animal use. Listings within the category describe the material in technical terms: identity, specification, form, storage condition and batch documentation. They carry no use, preparation or outcome information. What the category records, and how labelling and dispatch work within it, is set out in what research use only means in the UK.
The documentation layer
A certificate of analysis is the document that ties test results to one batch. A complete COA records:
- the compound name and identity reference;
- the lot or batch number, which should match the vial label;
- the analytical method behind each result;
- HPLC purity, reported as a percentage against that method;
- identity by mass spectrometry, reported as detected mass against expected mass, where that test was run;
- the test date and the issuing laboratory.
Purity and identity answer different questions. HPLC purity says how much of the detected material is the main component under a stated method; mass spectrometry says what that component is. A high purity figure on its own does not confirm identity. The full field-by-field explanation is in what is a COA for a research peptide.
How "lab tested" claims are backed
"Lab tested" on its own is a claim. It becomes evidence when it points to a specific record: a named method, a lot number that matches the vial, a test date and a laboratory. Check exactly which results a certificate reports. If a lot has an HPLC purity result but no mass-spectrometry identity result, the record should say so rather than imply one. What the phrase does and does not establish is covered in what "lab tested" means.
Index Peptides publishes its batch records and certificates, and its public lookup at /verify returns the record for a lot number printed on a vial. Read the certificate for the exact lot, including the results it actually reports.
Where to go next
Browse the catalogue for the documented formats currently listed, and use the compound pages for the identity reference behind each one. For any vial already in hand, the lot number is the starting point: it links the physical material to the one certificate that describes it.
FAQ
What are research peptides?
Research peptides are synthetic chains of amino acids made by chemical synthesis, most commonly solid-phase peptide synthesis, and supplied as laboratory reagents for in-vitro research. Each is defined by its sequence, CAS number, molecular formula and expected molecular weight, and each batch is documented on a certificate of analysis.
What does research use only mean for peptides?
Research use only (RUO) is a supply category. Material is supplied for in-vitro laboratory research and is not for human or animal use. Listings describe identity, specification, form, storage and batch documentation, and carry no use, preparation or outcome information.
How is a research peptide identified?
By its chemistry, not its name. The amino-acid sequence, CAS registry number, molecular formula and expected molecular weight are the identity reference. Similar names can describe different compounds, and supplied material is often a salt form, so the batch COA records the form actually tested.
What documentation should come with a research peptide?
A certificate of analysis for the specific batch, with a lot number that matches the vial label, the analytical method behind each result, HPLC purity, mass-spectrometry identity where that test was run, the test date and the issuing laboratory.
How can I check an Index Peptides batch?
Enter the lot number printed on the vial at /verify to see the batch record, and read the certificate for that lot at /coa, including which results it reports. Research use only. Not for human or animal consumption.
Research use only. Not for human or animal consumption.