- A vendor's certificate tells you about the batch they sampled. Testing a vial yourself is the only way to learn about the vial you hold.
- Budget £160–£360 per compound at the main laboratories. Endotoxin and sterility are separate line items again.
- The free community testing programmes are open to US residents only, so the cheapest route in this market is closed to the UK.
- Sending samples out of the UK is the step that goes wrong. Declare the contents accurately and expect the parcel to be opened.
Every vendor in this market will tell you their material is tested. Most of them are telling the truth about a sample, and the question you actually care about is a different one: what is in the vial in front of you.
The only way to answer that is to send it somewhere yourself. This is what that involves in the UK, what it costs, and where it tends to go wrong.
Everything below concerns material supplied for laboratory research use only, and the testing described is analytical chemistry on a sample — nothing here is about use in a person.
What a vendor certificate does and does not tell you
A certificate of analysis records what a laboratory measured in a sample it received. That is genuinely useful. It is not the same as a statement about the unit you were sent.
Large orders are not necessarily filled from one homogeneous pool, and a vendor who tests a sample from a production run and publishes that report has told you about the run, not about the individual vial. This is a fair criticism and it applies to everyone selling in this category, us included.
What narrows the gap is traceability: a batch number printed on the carton that matches the batch number on the report, and a report you can open on the laboratory's own server rather than the seller's. That is what our verification page is for, and it is what the article on batch traceability covers in detail. It narrows the gap. It does not close it. Only testing your own vial does that.
What it costs
Janoshik Analytical in the Czech Republic is the laboratory this market treats as the reference. Their published prices, at the time of writing, run roughly as follows.
- Single common peptides — BPC-157, CJC-1295, GHRP-2, PT-141 and similar: about $215
- Two-compound blends: about $320
- The common GLP-1 blind test, covering semaglutide, tirzepatide and retatrutide: about $360
- Less common compounds — cagrilintide, KPV, MOTS-c, Semax: about $450
- Endotoxin analysis: about $180
- Sterility testing: about $290
Two things are worth noticing. The first is that testing a single vial frequently costs more than the vial. The second is that endotoxin and sterility are separate purchases — a purity figure says nothing about either, and a sample can be chemically excellent and microbiologically poor.
Other laboratories accept this work and charge less: Freedom Diagnostics, Vanguard Laboratory, MZ Biolabs, Chromate and others are all active in this space. The trade-off is reputational rather than technical. Vendor guarantees in this market are, by convention, honoured on Janoshik results and frequently not on anyone else's, so a cheaper laboratory may cost you the ability to make a claim later.
The blind test is the one worth paying for
Most analyses are run against a compound you have named. You tell the laboratory what you believe the sample is, and they measure how much of it is there and how pure it is.
A blind test does not work that way. The laboratory is given a panel — semaglutide, tirzepatide, retatrutide — and determines which one it actually has. That is a stronger check, because it can detect a substitution rather than merely confirming a quantity.
If you are testing something to find out whether a vendor sent you what they said they sent you, this distinction is the whole point of the exercise. It is also why our own GLP-1 reports are run that way.
The free route is closed to you
The largest crowdsourced testing programme in this market publishes vendor leaderboards built from thousands of vials sent in by the public, and it does not charge for community submissions. Its free lane is restricted to US residents.
That is worth knowing before you plan around it. The cheapest independent verification available in this category is, as a matter of policy, unavailable in the United Kingdom. Group testing — several buyers splitting one analysis of the same batch — is the usual workaround, and shares of £20–£40 are typical. Janoshik accept group submissions if you ask.
The part that actually goes wrong
Shipping is the step people underestimate.
Sending research materials out of the United Kingdom means a customs declaration, and a declaration that is vague or inaccurate is the thing that causes trouble. Community reports describe parcels held for months, opened, and returned with vials physically damaged — in one account, a shipment to a laboratory was held by Border Force for around seven months and came back with a vial cut open and no paperwork explaining why.
We cannot verify individual accounts, and we are not going to pretend the risk is zero. What is clear is that this friction is asymmetric: it is considerably easier to get a vial independently tested in the United States than from here. That is part of why so little UK-specific testing data exists, and it is worth factoring into any plan that depends on verifying something yourself.
Our article on what happens at UK customs covers the inbound direction. Outbound is the same machinery pointed the other way.
What to ask for
If you are commissioning a test, the useful package is:
- Identity — ideally blind, so the laboratory determines the compound rather than confirming your assumption
- Content — how much is present, in mg per ml or mg per vial, against what the label says
- Purity — the proportion of the material that is the named compound
- Endotoxin, if the work requires it — separate, and not implied by any of the above
If you would rather start from what a supplier should already be publishing, the research peptides hub sets out the five things worth checking before you order anywhere. And when the report comes back, verify it. A report is a PDF and PDFs are editable; the check that means anything is entering the task number and key on the laboratory's own site. We wrote how to tell a real Janoshik report from a fake one for exactly that.
Sources
Questions this article answers
How much does peptide testing cost in the UK?
Expect roughly £160–£360 per compound at the main laboratories, with the common GLP-1 blind test at the upper end. Endotoxin analysis and sterility testing are charged separately, at roughly £140 and £220 respectively. Testing one vial often costs more than the vial did.
Is there free peptide testing in the UK?
No. The main crowdsourced programme that publishes free community results restricts its free lane to US residents. Group testing, where several buyers split the cost of one analysis, is the usual way UK researchers reduce the per-person cost.
Which laboratory should I use?
Janoshik Analytical is the one this market treats as the reference standard, and vendor guarantees are conventionally honoured on their results and often not on others'. Freedom Diagnostics, Vanguard Laboratory, MZ Biolabs and Chromate are all cheaper and all active in this space.
Can I send a sample from the UK to a laboratory in Europe?
Yes, but it is a customs declaration and the contents must be described accurately. Community reports describe long holds, opened parcels and damaged vials. It is materially harder to do from the UK than from the United States, and worth planning for rather than assuming.
Does a purity figure tell me whether something is sterile?
No. Purity, endotoxin and sterility are three separate measurements. A sample can return an excellent purity figure and still fail an endotoxin test, and a standard purity analysis does not look for either.
Want the certificate for a real batch?
Name a compound and we'll send the manufacturer's HPLC-MS certificate for the batch you would receive — before you order, no account needed.