Tests, COAs & verification
Peptides sold for research are unregulated chemicals. Purity, identity, and endotoxin levels vary wildly between suppliers — independent third-party testing is the only way to know what is really in the vial.
Why third-party testing matters
A vendor COA is useful but it is only one side of the story. Independent, third-party testing verifies that the product you actually received matches the label — before you inject anything into a research subject.
Mislabelled or wrong peptides are common
Purity below 98% means unknown impurities
Endotoxin contamination is invisible but dangerous
A single batch can differ from the one tested by the vendor
The core tests, explained
Every COA you receive should include most of these. Here is what each one actually measures.
HPLC Purity
The most important number. HPLC separates the peptide from impurities and reports what percentage of the sample is actually your peptide. Look for 98% or higher.
LC-MS / Mass Spectrometry
Confirms the molecular weight of the peptide. This tells you the compound is what it claims to be, not just that something is in the vial. A mass match within ±0.5 Da is typically shown on the COA.
Endotoxin (LAL Test)
Measures bacterial endotoxin contamination in EU/mL. A research-grade target is <5 EU/mL, with stricter protocols aiming for <1 EU/mL. High endotoxin is the most common cause of injection-site reactions.
Sterility Test
Checks for viable microorganisms (bacteria, yeast, mould). Biological products intended for injection must pass this or the sample is unusable.
Amino Acid Analysis / Sequence
Verifies the amino acid composition and, in advanced panels, the actual sequence. This catches truncated chains and synthesis by-products that mass alone cannot reveal.
Residual Solvents
Detects leftover synthesis solvents (acetonitrile, TFA, etc.). TFA counter-ion is expected in most peptides, but other solvents should be below ICH limits.
How to read a COA
Not all COAs are created equal. These are the fields you should look for, and what a good value looks like.
Red flags to watch for
- No batch number
- Purity reported as ">95%" without an exact number
- No mass spec match data
- COA is identical month after month (often copied)
- No lab contact or certificate number
Popular third-party labs
Independent labs accept mailed-in samples and publish anonymised results. These are the names you will see most often in community testing.
Janoshik
The most widely used lab in the peptide community. Based in Europe, accepts international samples, publishes all results publicly with a searchable database. Around 2 weeks turnaround.
MZ Biolabs
A professional analytical lab in the US offering high-quality LC-MS/MS, amino acid analysis, and custom panels. Generally used by vendors and advanced researchers; more expensive than Janoshik.
Peptide Test
Originally a German forum-based testing project that grew into an independent lab. Offers affordable panels and publishes results in an open database.
Energy Control (recreational)
A harm-reduction lab in Spain that tests all substances, including some peptides in recent years. Lower cost, remote testing by code, but peptide panel is limited.
Always check the current service offering and shipping instructions on the lab’s official website before mailing a sample. Addresses and panels change.
PepEmu is not affiliated with, endorsed by, or compensated by any of the labs listed above. Details are provided for educational reference only.
Rough pricing guide
Prices are approximate, in USD, and vary by lab, panel size, and current promotions. Group-buy testing through community forums is the cheapest way to test a large batch.
Many labs offer discounts for 5+ samples. A group buy of 10 peptides can easily cut per-sample cost to under $20 each for a basic identity check.
How to submit a sample
A simple 6-step process that works for most labs.
Order a test kit / request a unique sample code from the lab website
Reconstitute the peptide following the lab’s instructions (usually 1 mL bacteriostatic water)
Transfer the required volume into the provided sterile vial
Label with the sample code and pack with the return form
Mail to the address provided (local shipping avoids customs delays)
Wait 1–3 weeks, then look up your results by code on the public database
Found a result you want to verify?
Check the peptide’s profile, then use the calculator to plan your research protocol.