A supplier's COA tells you what was in their sample. An independent test tells you what is in yours. If you are buying a bulk batch, onboarding a new supplier, or the price looks too good, sending one vial to a third-party lab is cheap insurance.
This guide covers the labs buyers use most, which tests to order, how to read the result, and how to confirm a report is genuine.
The Three Labs Buyers Use Most
| Janoshik Analytical | Vanguard Laboratory | Freedom Diagnostics | |
|---|---|---|---|
| Based in | Czech Republic | Olympia, Washington, US | Franklin, Tennessee, US |
| ISO 17025 | No | Yes, states A2LA certificate 6377.01 | Not stated |
| Base test price | $215, $290 or $450 depending on the peptide | $250 for one vial | Shown on the submission form |
| Stated turnaround | About 7 business days, plus shipping | 5 to 8 business days | 1 to 3 business days on average |
| Check a report at | janoshik.com/verification | verifiedbyvanguard.com | Public COA lookup on its site |
Prices and turnaround as published by the labs or captured by third-party trackers in September and October 2026. Labs change prices without notice, so confirm before you ship.
Janoshik
Janoshik is the lab most often named on peptide COAs. Its base test covers identity, amount per vial and HPLC purity, priced at $215, $290 or $450 depending on the peptide. Add-ons include endotoxin ($180), sterility ($290), heavy metals ($105) and an LC-MS contamination screen ($205). Rush service doubles the price. Samples ship to its single facility in the Czech Republic, so add international shipping and customs time.
Janoshik also offers blind testing. Its GLP-1 blind test ($360) checks whether a sample contains semaglutide, tirzepatide or retatrutide without you declaring which, and a fully blind screen with no declared compound costs more.
Janoshik is not ISO 17025 accredited. That does not make its results wrong, but a Janoshik report will not satisfy a requirement for accredited data, such as a formal supplier qualification file.
Checking a Janoshik report: every report has a task number at the top and a unique key at the bottom. Enter both at janoshik.com/verification, or scan the QR code. A report counts as genuine only if it matches the version stored in Janoshik's system. A cropped screenshot missing either number cannot be checked.
Vanguard Laboratory
Vanguard states it is ISO/IEC 17025:2017 accredited through A2LA, which makes it the stronger choice when a result has to stand up to scrutiny. Its $250 base panel covers purity, quantity and identity for one vial. Endotoxin is $210 and sterility $150 (sterility needs an extra vial and takes about 14 days). Bundles of three and four tests are $550 and $700. Reports can be confirmed on its public portal at verifiedbyvanguard.com.
Freedom Diagnostics
Freedom Diagnostics opened in Franklin, Tennessee in 2023 and is the fastest of the three, averaging 1 to 3 business days. It runs HPLC for purity and LC-MS for identity, and also offers endotoxin, net content, sterility and heavy metals testing. Prices appear on its submission form. Every report has an accession number you can search, along with the company name, in its public COA lookup.
Which Tests to Order
| Test | What it tells you | When to order it |
|---|---|---|
| HPLC purity | How much of the sample is the main compound versus impurities. | Always. |
| Identity (mass spec) | Whether the main compound is the peptide on the label. | Always. Purity means nothing if it is the wrong peptide. |
| Quantity | How many mg of peptide are actually in the vial. | When you pay per mg or a vial looks underfilled. |
| Endotoxin (USP <85>) | Bacterial endotoxin contamination. | For cell work or anything formulated for injection. |
| Sterility (USP <71>) | Whether live microorganisms are present. | For finished sterile products. |
| Heavy metals (ICP-MS) | Lead, arsenic, cadmium, mercury and similar. | Bulk API orders and new manufacturers. |
| TFA | Leftover trifluoroacetate from synthesis. | Sensitive assays, or when the spec calls for an acetate salt. |
For most buyers, purity plus identity is the minimum. Add quantity if you pay per mg, and endotoxin if the material is going anywhere near cells.
HPLC Peptide Testing: Reading the Result
HPLC separates a sample into its components and reports the main peak as a percentage of everything detected. A clean result shows one dominant peak at the expected retention time. Look at the chromatogram, not just the number. Shoulders on the main peak or a cluster of small peaks usually mean related impurities, such as shortened or incomplete sequences.
HPLC cannot tell you the compound is the right one. A vial can be 99% pure and still hold the wrong peptide, which is why identity by mass spectrometry belongs on every report. For reading a supplier's paperwork, see our guide to verifying a peptide COA.
How to Test Peptides, Step by Step
- Pick the lab based on what the result is for. Vanguard if you need accredited data. Janoshik or Freedom Diagnostics for fast screening.
- Choose the tests from the table above and check the current price.
- Send one sealed vial from the batch you received and record its batch number.
- Consider a blind test. Letting the lab identify the compound without being told removes any doubt that the label steered the result.
- Verify the report on the lab's own site, not through a link someone sent you.
- Treat it as batch-specific. A new lot needs a new test.
How Much Does Peptide Testing Cost?
A base test for one peptide runs about $215 to $450. A full panel with endotoxin, sterility and heavy metals runs about $700 to $800. Whether it is worth it depends on the order:
- Small first order: usually not worth testing unless something looks off.
- Mid-size batch: test one vial for identity and purity.
- Bulk order or new manufacturer: test before you scale, and test each new lot.
For B2B Buyers
If you are sourcing at volume, ask the supplier which lab tests each batch, whether those reports can be verified, and whether you can commission your own test before accepting a shipment. A supplier confident in its product will not object. In our directory, the third-party tested tag marks suppliers that publish independent results, and our free COA Spec Checker lines up claimed and measured values from a COA PDF.
FAQ
Can you test peptides at home?
No. Purity and identity need HPLC and mass spectrometry. No home kit can tell you what a peptide is or how pure it is.
What is the most accurate lab test for peptides?
No single test is enough. HPLC for purity plus mass spectrometry for identity is the standard pairing. LC-MS runs both on one instrument.
Is Janoshik legit?
Yes. Janoshik is a real, widely used lab with a public verification system. The usual problem is not the lab but fake or reused Janoshik PDFs, so always check the task number and key at janoshik.com/verification.
What is an acceptable endotoxin level?
It depends on how the material will be used. For injectable products, USP <85> sets the limit per dose based on body weight, so there is no single number that fits every peptide. Ask the lab or check your specification.