Written for buyers · No supplier-specific claims · Use it on any vendor, including us
Six checks before you place a first order
Most buyers lose money on peptide sourcing through the same three failures: a certificate that belongs to someone else, a purity number with no supporting chromatogram, or a supplier who cannot answer basic questions about their own production line. None of these are obvious if you don’t know what to ask for.
This guide applies to every supplier in the industry, including us.
Six fields to check on every COA
- Lot number matches the physical label. A certificate for a different lot proves nothing about what is in your vial.
- Test date is recent. Peptides degrade. A certificate older than a few months describes material that no longer exists.
- Purity figure and method appear together. “98% pure” means nothing without knowing whether it came from HPLC and how purity was calculated.
- A chromatogram is attached. A bare number can be typed by anyone. A chromatogram can be checked for plausibility.
- Retention time and peak assignment are stated. This lets you confirm the peak being measured is actually your product.
- The signatory is affiliated with the lab. A certificate signed by “QC Department” with no traceable identity carries no weight.
How to read an HPLC chromatogram
Purity is the area of the main peak divided by the total integrated area. On a well-run sample you should see one dominant peak with small flanking impurities. Three things worth checking:
- Is the main peak actually dominant? If several peaks are comparable, the reported purity will not be high, whatever the certificate claims.
- Does the trace look edited? Stair-stepped baselines, clipped axes and sudden peak onsets can indicate a spliced image.
- Can you find the same chart elsewhere? Reverse image search catches recycled chromatograms. If the same figure appears under a different supplier’s name, it is copied.
Six questions that separate a manufacturer from a reseller
- Can you send unedited production-line photos, timestamped and geotagged?
- Will you provide COAs for three consecutive lots of the same product?
- Do you accept blind third-party testing before the first bulk order?
- Is your production licence verifiable, and by which authority?
- Do you run your own laboratory, or submit samples externally?
- Will you provide the full molecular formula and molecular weight for each product?
A reseller will hesitate or decline on at least two of these. A manufacturer answers all six without being asked twice.
Common failure modes
Borrowed certificates
A genuine COA lifted from another batch or another supplier. Defeated by asking for three consecutive lots and checking lot numbers against labels.
Quoted purity without data
High purity claimed in marketing copy with no batch document behind it. Ask for the chromatogram, not the number.
Cold-chain breaks
Material stored or shipped outside −20 °C degrades regardless of the certificate it shipped with. Ask how the lane is monitored.
Relabelling
Bulk material decanted and re-labelled as originating elsewhere. Check vial closure, labelling quality and whether packaging matches the described process.
What we commit to
Every claim on this site is traceable to a document or a third-party record. We encourage blind testing before your first order, and we will ship to any accredited laboratory you nominate. If you find a discrepancy anywhere on this site, contact us directly and we will address it in writing.
All products are sold for research use only. They are not intended for human consumption and are not a food, drug, or medical product. No claims are made regarding therapeutic efficacy.