Research Peptides for Sale: How to Evaluate a U.S. Supplier
For in vitro laboratory research use only. This guide covers documentation and labeling only. It is not a guide to using any material, and Peptix makes no claims about the effects of any material it sells.
Choosing where to source research peptides in the United States usually comes down to one question: can the supplier show you, in writing, what was tested and how? Product photos and descriptions tell you very little. Documentation tells you a lot. This checklist covers the five things a laboratory can check before placing an order, using only information a supplier should be able to show publicly.
1. A public COA that matches a lot number
A Certificate of Analysis (COA) is a report from a testing laboratory. It is only useful if it can be tied to the material you receive. Look for a COA page that lists each current lot ID next to its certificate, so you can match the lot printed on a vial label to a specific report.
Watch for certificates with no lot number, a lot number that does not appear anywhere on the product, or a single generic report reused across several products. A certificate reports results for the sample tested. It is not a guarantee for other lots.
On the Peptix peptide COA lookup page, each current lot is listed with its lot ID, the testing lab, the report date, the method and the result.
2. An independent, named laboratory
A COA should name the laboratory that performed the analysis. An independent third-party lab is preferable to in-house testing, because the report comes from an organization other than the seller.
Useful questions:
- Is the laboratory named on the certificate?
- Does the lab offer a way to look up the report on its own website, for example with a search code?
- Is there a report date, so you can tell how recent the testing is?
Current Peptix lots are tested by Freedom Diagnostics, an independent laboratory, and each listed certificate has a search code that can be checked on the lab’s own site.
3. The right methods for purity and identity
Two different questions are answered by two different methods:
- Purity is usually measured by HPLC-UV (high-performance liquid chromatography with UV detection). The result is reported as a percentage: the share of the main peak in the chromatogram.
- Identity is usually confirmed by LC-MS (liquid chromatography with mass spectrometry), which checks that the measured mass matches the expected compound.
A report that gives a purity percentage but no identity result, or the reverse, answers only half the question. Our HPLC purity explainer covers how a purity result is read.
4. U.S. shipping and clear policies
For U.S. laboratories, a U.S.-based supplier generally means domestic shipping and policies written for U.S. customers. Before ordering, check that the shipping policy, refund and returns policy, and terms are published and easy to find, and that contact details are listed. These are basic signs that a business expects to be accountable for its orders.
5. Research-use-only labeling
Research peptides in the U.S. are sold for laboratory research. Labeling should say so clearly and consistently: on the product page, the vial label and the documentation. A supplier whose pages describe uses outside the laboratory, or make claims about what a material does, is not presenting it as a research material.
Peptix product pages and the COA page carry the same statement: For research use only. Not for human or animal use.
A quick checklist
- Lot ID on the vial matches a lot ID on a public certificate
- Certificate names an independent testing lab and a report date
- Purity by HPLC-UV and identity by LC-MS are both reported
- The report can be confirmed on the lab’s own site
- Shipping, returns and terms are published
- Research-use-only labeling is consistent everywhere
Current Peptix lots
| Product | Lot ID | Purity (HPLC-UV) | Identity (LC-MS) | Measured net content per COA |
|---|---|---|---|---|
| BPC-157 10 mg | BC-20260521-01 | 99.26% | BPC-157 | 12.71 mg (labeled 10 mg) |
| TB-500 10 mg | TB-20260521-01 | 99.79% | thymosin beta-4 | 12.15 mg (labeled 10 mg) |
| BPC-157 / TB-500 20 mg | BB-20260521-01 | 99.15% | BPC-157 and thymosin beta-4 | 13.68 mg BPC-157 + 11.17 mg thymosin beta-4 (labeled 10 mg + 10 mg) |
Source: the Peptix COA page, Freedom Diagnostics reports dated July 8, 2026. A certificate reports results for the sample tested. It is not a guarantee for other lots.
You can browse the full range of research peptides with their linked lot certificates, including BPC-157 10 mg.
Frequently asked questions
What should a research peptide supplier be able to show?
A supplier should be able to show a public Certificate of Analysis for each current lot, the name of the testing laboratory, the report date, and results for both purity and identity.
What does lot-matched mean?
Lot-matched means the lot ID printed on the vial can be found on a specific certificate. A certificate reports results for the sample tested. It is not a guarantee for other lots.
Which methods are used for purity and identity?
Purity is usually measured by HPLC-UV and reported as a percentage. Identity is usually confirmed by LC-MS, which checks that the measured mass matches the expected compound.
Who tests Peptix lots?
Current Peptix lots are tested by Freedom Diagnostics, an independent laboratory. Each listed certificate has a search code that can be checked on the lab’s website.
For research use only. Not for human or animal use.
