Where to Get Peptides Tested: Labs & Prices

You can send a sealed vial to an independent analytical lab and get an HPLC purity number back in about a week. The realistic options are three: mail-in peptide labs built for this exact traffic (Janoshik Analytical in Slovakia, Colmaric Analyticals and MZ Biolabs in the US) at roughly $50–$150 per sample; contract research organizations like Eurofins, SGS, or Intertek, at $300–$1,200 per method with 2–4 week queues; and university proteomics or mass-spec core facilities, which run external samples at $75–$400 depending on the institution and whether you have an academic affiliation. For most people asking this question, the mail-in labs are the right answer on cost and turnaround. The rest of this page covers what those tests actually prove, what they don't, and when paying for one is a waste of money.

The Three Places That Will Actually Take Your Sample

Mail-in peptide-specific labs. These exist because the research-material market created demand for cheap single-vial verification. Janoshik has been the volume leader for years and publishes a menu: HPLC purity and quantity in the $40–$60 range, LC-MS identity confirmation adding another $30–$50, with reports typically returned 3–10 business days after the sample lands. Colmaric Analyticals runs a US-domestic operation at a higher price point — commonly $90–$160 for a combined purity-and-mass panel — which matters if you don't want a vial crossing a customs border. MZ Biolabs in Arizona is mass-spectrometry-first and is the better fit when your question is "is this molecule what the label says" rather than "what percent of the peak area is the main component."

Contract research organizations. Eurofins, SGS, Intertek, and the regional CROs will run the same chemistry under a documented quality system with audit trails and, if you pay for it, method validation to ICH Q2(R2). Expect $300–$600 for a single validated HPLC assay, $800–$1,500 if you need a stability-indicating method developed, and 15–25 business days. You are not buying better chromatography. You are buying defensibility — a report that survives an auditor, a grant review, or a legal process.

University core facilities. An R1 proteomics core will often run an intact-mass measurement for $75–$200 for outside submitters. Turnaround is unpredictable — I've seen 4 days and I've seen 6 weeks — and many cores restrict external work to collaborators. Worth a call if you're already affiliated.

What Each Test Actually Measures

The single biggest misunderstanding in this market: purity and identity are different questions, answered by different instruments, and one does not substitute for the other.

RP-HPLC with UV detection (typically a C18 column, 214 nm or 220 nm for the peptide bond) gives you relative peak area. A "99.1% purity" result means the main peak is 99.1% of total absorbance at that wavelength. Anything that doesn't absorb — water, salts, mannitol, the acetate or TFA counterion — is invisible. A vial that is 40% water by mass can still report 99% HPLC purity, honestly.
Quantity assay answers the separate question of how much peptide is in the vial, usually against a reference standard. This is where most real-world discrepancies show up. A ±5% variance is normal analytical noise; a vial labeled 10 mg that assays at 7.2 mg is a 28% shortfall and a supplier problem.
LC-MS or MALDI intact mass confirms molecular weight to within roughly 1 Da on a decent instrument. It tells you the mass matches. It does not confirm sequence order, and it will not distinguish L- from D-amino acid substitutions, which are mass-identical.
MS/MS sequencing is the test that confirms the actual amino acid order. It costs more — usually $150–$400 — and almost nobody orders it, which is why "verified by mass spec" is a weaker claim than it sounds.
Everything else — water content by Karl Fischer, residual solvent by GC headspace, endotoxin by LAL, bioburden, counterion ratio by ion chromatography — is a separate line item, typically $80–$250 each, and is essentially never included in a $60 mail-in panel.

A purity percentage on a certificate is one number from one instrument at one wavelength on one vial. Treating it as a complete quality picture is the most common analytical error in this market.

Cost, Logistics, and the Arithmetic

Sending a sample means sacrificing it. Most labs want 1–5 mg of material, which for a typical 5 mg or 10 mg vial means the whole vial or half of it. Add international shipping at $15–$45 for a small parcel with tracking, plus the real possibility of a customs hold adding 5–15 business days.

So the all-in cost of independently testing one vial runs roughly:

Mail-in HPLC + MS panel: $80–$150
Shipping: $15–$45
Sacrificed material: $25–$90 at typical unit pricing
Total: $120–$285 per lot, per compound

Against a $40 vial, that's a 3–7x multiplier on the thing you're verifying. Against a 100-vial wholesale lot, it's under 1% of order value and obviously correct. The economics flip entirely on volume — which is the actual decision variable, not "should I test or not." See wholesale for how lot sizing changes that math.

When Third-Party Testing Is Not Worth Your Money

This section costs us sales, and it's the most useful part of the page.

Don't pay for a test that duplicates one you already have. If your supplier provides a lot-specific certificate of analysis with the actual chromatogram — retention time, peak table, integration, gradient conditions, column, injection volume, instrument, analyst, date — and the lot number on that document matches the lot number printed on your vial, a second $120 test is buying you very little. A generic CoA with no lot number and no chromatogram image is worth nothing and should be treated as absent. That distinction is the entire game. Our quality page shows what a lot-matched document set looks like.

Don't test a single vial and conclude anything about a lot. One vial is n=1. Fill-weight variance, stopper seal failures, and position-in-run effects are real. A single passing result tells you that one vial was fine on the day it was pulled. If you genuinely need lot-level confidence, you need 3+ vials sampled across the fill run, which triples the cost and is rarely justified outside a regulated setting.

Don't expect testing to catch what it can't see. A mail-in HPLC/MS panel will not detect: endotoxin, bacterial contamination, particulate matter, residual solvents from synthesis, heavy metals, or incorrect stereochemistry. If any of those are relevant to your work, a $60 panel gives you false confidence, which is worse than no data.

Don't do this if the material is already open or ambiguously stored. A vial that has been sitting at room temperature for three weeks is measuring your logistics, not the supplier's chemistry. Lyophilized peptides are generally shipped and held at 2–8°C for short periods and stored at −20°C for long-term, with typical stated shelf life of 24–36 months sealed. Degradation from mishandling shows up as new peaks, and you will be paying $120 to blame the wrong party.

Don't order a validated CRO method for a routine purchase. The $600 Eurofins report and the $60 Janoshik report will produce very similar purity numbers on the same sample. You pay the difference for the quality system, not the chemistry. If nobody is going to audit you, the premium is dead weight.

And the plain version: if you are not a qualified researcher purchasing documented reference material for laboratory work, no analytical result changes what these materials are or are not approved for. Read research use only before spending anything, on testing or on material.

How to Read the Report You Get Back

Check the lot number appears on the report and matches your vial. A report without a lot reference cannot be tied to anything.
Look at the chromatogram, not the summary number. A clean 98.5% with one small late-eluting impurity is a different material than 98.5% with six impurities at 0.2% each.
Check the gradient and run time. A 12-minute isocratic run can hide impurities that a 30-minute gradient resolves. Short methods flatter samples.
Compare quantity assay to label claim and treat anything beyond ±10% as a supplier conversation, not analytical noise.
Note the detection limit. Most UV methods report down to about 0.05–0.1% peak area. Below that, "not detected" means "not detected by this method," not "absent."

If a result disagrees with the documentation that shipped with a material, the productive move is to send the report and the lot number to the supplier and ask them to produce their retained-sample data for the same lot. A supplier who keeps retention samples and can pull the original run has a real system. One who cannot is telling you something. You can reach us through contact with a lot number and a report, and further comparisons of supplier documentation practices are collected in the library.

Testing is a verification layer, not a substitute for buying from a source that documents its lots in the first place. The cheapest reliable path is the boring one: buy material with lot-matched analytical documentation, spot-check independently on new suppliers or large orders, and skip the $120 confirmation on every $40 vial from a source that has already shown you its chromatograms.