How to get your peptides tested — and what to test them for

Why independent testing matters

A certificate of analysis hosted by the seller is a self-report. Independent audits of the research-peptide market have repeatedly found a large share of products — in some analyses roughly a third — failing to match their label claim, from a few percentage points of missing purity to vials containing the wrong compound entirely. The only quality signal that does not originate with the seller is a report from a lab you chose and paid yourself.

• A vendor COA proves the vendor owns a printer. A third-party COA proves a named lab measured a specific lot on a specific date.
• Counterfeit and underfilled GLP-1 products are a documented problem: the FDA has issued repeated warnings about counterfeit semaglutide and tirzepatide, including vials with the wrong salt form or no active ingredient.
• Testing one vial from a new supplier tells you more about that supplier than a hundred reviews, because reviews cannot see inside the vial.
• If you are running a long protocol where consistent input matters, a one-off test costing $100–300 is small money against months of unknown material.

What to test for — and what each result means

Labs sell these as separate panels. For a first check on a new supplier, purity plus identity is the minimum useful pair; the others answer specific safety questions.

• Purity (HPLC): what percentage of the UV-absorbing material is the target peptide. Reported with the chromatogram — a single dominant peak is what you want to see. The standard minimum people look for is around 98–99%.
• Identity (mass spectrometry): the measured molecular weight must match the theoretical weight of the sequence, typically within about 1 Da. This answers 'is it even the right molecule' — the question purity alone cannot answer.
• Net peptide content: how much actual peptide is in the vial after accounting for water and counter-ions (TFA or acetate). A vial labeled 10 mg can legitimately contain less active peptide than the label suggests; NPC tells you how much.
• Endotoxin (LAL test, reported in EU/mL): bacterial residue from synthesis or handling. This is a safety test, not a quality nicety — injected endotoxin causes fever and inflammatory reactions even when the peptide itself is pure.
• Heavy metals (lead, mercury, cadmium, arsenic) and sterility: not included in standard purity panels. Ask for them explicitly if the product is for anything other than analytical reference.
• Note what a purity panel does NOT cover: activity, sterility, endotoxins, heavy metals and pH are separate tests, and a '99% pure' COA says nothing about any of them.

How to actually get a vial tested, step by step

The process is simpler than it sounds: every lab below accepts samples shipped directly by individuals, and none requires you to be a company.

• Pick the lab and order the panel online first — you get a submission ID to write on the parcel before anything ships.
• Plan on sacrificing one vial or about 10–20 mg of powder. Most labs need that much to run HPLC and mass spec properly.
• Ship the sample as directed by the lab. Lyophilized (freeze-dried) powder is stable at room temperature for the shipping window; keep it sealed and dry. Declare it honestly as the lab instructs for customs.
• Typical cost is $100–300 per sample depending on the panel, with turnaround around 5–15 business days from receipt.
• When the report comes back, check three things before the numbers: the lab's name is on it, the report is dated, and the lot or sample ID matches what you sent.
• Verify the report with the lab, not the seller. Janoshik, for example, publishes results in a public database where anyone can confirm a report number — a PDF a seller emails you proves nothing on its own.
• Keep the COA with the lot number of the vials it covered. A test of lot A says nothing about lot B from the same seller.

Labs that test peptides, by country

Every lab listed here accepts samples directly from individuals, sells no peptides itself, and publishes its methodology. DoseRoutine has no affiliation with any of them — services and prices change, so confirm details with the lab before shipping anything.