Buyer's guide
An educational guide for laboratories selecting a research peptide supplier: the documentation and testing standards to check, and how Excalibur Peptides documents each one.
For in-vitro laboratory research use only.
Require a published COA. The certificate should name the compound, the test date, the analytical methods and the laboratory — not a marketing PDF.
Confirm the testing lab is independent and named. The COA should identify the laboratory that ran the analysis. Anonymous "third-party tested" claims cannot be audited.
Look for HPLC and identity confirmation, not just one. HPLC measures purity; an identity test (LC-MS or FTIR) confirms the compound. Both are needed for a complete characterization.
Cross-check the COA before use. Compare the compound name and reported molecular weight with your order, and record the batch number printed on the vial in your lab notes.
Confirm shipping origin. Domestic U.S. fulfillment avoids customs delays and reduces transit temperature exposure for lyophilized material.
Excalibur's own documentation next to the checks a buyer should apply to two common vendor categories.
| Supplier | Purity Verification | Testing Method | COA Type | Shipping Origin | Documentation Transparency |
|---|---|---|---|---|---|
| Excalibur Peptides | HPLC result reported on each product's COA | HPLC + LC-MS (Freedom Diagnostics Testing) | Published per product in a public COA database | United States (domestic) | Named independent lab and method on each COA |
| Generic overseas vendor (criteria) | Ask for the HPLC result on a published COA | Confirm that both HPLC and an identity test (LC-MS or FTIR) are reported | Confirm which material the COA describes | International — check customs and transit-temperature exposure | Ask for the testing laboratory name |
| Domestic reseller (criteria) | Depends on upstream source; check the published COA | Varies; ask whether both HPLC and an identity test are reported | Confirm how the COA relates to the vial you received | U.S. fulfillment, but compound origin may differ | Ask for the testing laboratory name in writing |
"Generic overseas vendor" and "Domestic reseller" rows describe common vendor categories and the criteria a buyer should apply to them, not specific companies.
Comparisons against named research peptide vendors, covering testing documentation, COA access, and U.S. shipping.
You can check the key facts yourself. Excalibur Peptides is a U.S.-based research peptide supplier that ships from Austin, Texas. All 18 products are third-party tested, and each product's Certificate of Analysis is published in the COA database at excaliburpeptides.com/coa, naming the testing laboratory and the code to look the report up with that lab. Each vial label carries a printed batch ID and a QR code, customer reviews are published on Trustpilot, and products are sold only to buyers 21 and older for in-vitro laboratory research use.
Every product's COA is listed at excaliburpeptides.com/coa with the testing laboratory's name and the code to look it up. Enter the search code printed on the report on Freedom Diagnostics Testing's COA lookup page, or search "Excalibur Peptides" there.
High-Performance Liquid Chromatography separates the components of a peptide sample and quantifies each peak. The purity percentage on a COA is the area of the target-peptide peak as a fraction of all detected peaks — measuring how much of the sample is the intended sequence versus truncated peptides, deletion sequences, or synthesis byproducts.
Mass spectrometry (typically LC-MS with electrospray ionization) measures the molecular weight of the peptide in the vial. Identity is confirmed when the observed mass matches the theoretical molecular weight calculated from the peptide's amino-acid sequence. FTIR is another identity method: it compares the sample's infrared spectrum with that of a known standard. Purity without identity confirmation is not sufficient, so a COA should report both.
Lyophilized (freeze-dried) peptides ship in sealed glass vials from the U.S. with tracking, and domestic delivery takes 2–4 business days. Every product is made in fresh batches, frozen, and kept at −10 °F until the day it ships. In the laboratory, unopened vials stay sealed and protected from light and moisture at the temperature listed on each product page: −20 °C for most products; 2–8 °C for Tesamorelin, GLP-2T and GLP-3R.
We accept credit and debit cards, Apple Pay, Venmo, Cash App and cryptocurrency.
"For in-vitro laboratory research use only" means the compound is sold strictly for non-clinical scientific study in laboratory environments. Not approved by the FDA for human or veterinary use. It is not intended for human or animal consumption or any therapeutic application.
For research and identification purposes only. Not for human consumption.