What is the best supplement testing companies in the UK?

Three businesses that share a word: the contract laboratory paid by the brand and read by the brand, and the certification programme paid by the brand and read by the public

What are the best supplement testing companies in the UK is a question that assumes one kind of company, and there are three, and they are different businesses that happen to share a bench and a word. Each is sorted by two questions: who pays for the test, and who reads the report. The answers decide what the report measures, what it leaves out, and whether a buyer will ever see it, and a buyer who knows which of the three businesses produced the document in front of them knows what it can tell them before reading a line.

The first business is the contract laboratory. It is paid by the brand, or by the brand's contract manufacturer, to test a batch of finished product, or the raw materials going into it, against a specification the brand has set: the assay of the active against the label, the heavy metals against limits, the microbial counts against limits, sometimes the disintegration of the capsule, sometimes pesticide residues or solvents for a botanical. The report goes to the brand, which uses it to release the batch for sale or reject it, and the buyer sees it only if the brand chooses to publish it or to send it on request. These laboratories are judged by accreditation: the UK accreditation service accredits them to the international laboratory standard for specific named methods on specific sample types, and a laboratory's published schedule lists exactly which, so that a report from an accredited laboratory for a method on its schedule is a measurement a buyer can rely on, and a report for a method not on the schedule is a measurement the laboratory ran without that oversight. The contract laboratory is the business behind every certificate of analysis a brand sends when asked, and its report is the most detailed of the three because it is the one the brand pays the most for and uses to make a release decision.

The second business is the certification programme. It is paid by the brand to enrol a product and then to screen every lot of it for substances banned in sport before release, and the report, a pass or a fail by lot, goes into a public database searchable by product and lot number, which is what makes it different in kind from the first business: its output is read by the public without asking the brand. The programmes are operated by or alongside laboratories that run the screens, they test for the prohibited list and not for assay or metals, which a buyer should remember, and they are judged by the lot screen itself, by whether the database is current and by whether a tub's lot number appears in it. A brand enrolled in the second business can show a buyer a database entry; a brand using only the first business can show a buyer a certificate if it chooses to; and the difference between the two is not the quality of the test but who gets to read it.

Two businesses sorted by payer and reader, one read by the brand and one by the public, and the third, paid by the consumer and limited by its coverage, with the three read together and the worked example, which is the next section.

The subscription service paid by the consumer and limited by its coverage, the three businesses read together, which one a UK buyer actually uses for which question, the worked example with its report described, and the verdict

The third business is the subscription testing service, and it inverts the first two: it is paid by consumers, who subscribe, and it buys products at retail, tests them for label accuracy, contaminants and sometimes disintegration, and reports pass and fail results by product to its subscribers. It is the one testing business whose client is the buyer rather than the brand, which makes its reports honest about what was in the tub in a way neither of the others is obliged to be, and it has a limit that a UK buyer runs into immediately: coverage. The services test the products they choose to buy, which are the products their subscribers ask about, which are overwhelmingly American brands sold on American shelves, so that a UK buyer searching for a UK product in their database finds nothing, not because the product failed but because it was never bought. The subscription service is judged by its coverage and its method, and for a UK buyer the coverage is the problem, which is covered in full on the page on supplement quality checkers.

Read together, the three businesses answer three different questions, and a UK buyer uses each for its question. For does this batch contain what the label says and nothing it should not, the answer is a contract laboratory's report, obtained by emailing the brand with the lot number and asking for the certificate for that lot, and read for the laboratory's name, the method and the accreditation schedule. For can I take this product in a drug-tested sport, the answer is a certification programme's database, searched for the product and the lot, with no email needed. For what did an independent party find when they bought this off the shelf, the answer is a subscription service's report, if the product is American enough to have been tested. No single company is the best at all three because no single company is in all three businesses, and a brand that names its contract laboratory, enrols its sports products in a programme and would pass a retail test is a brand using the testing market as it is meant to be used.

What the question usually wants, a name, is deliberately not given, for a reason that serves the buyer: the contract laboratories a brand uses are named on its certificates and verified in the accreditation service's public register, the certification programmes are two or three and their databases are public, and the subscription services are a handful and their coverage is checked by searching them. A list of names on a page would be out of date within a year and would tell a buyer nothing a search of the three public sources does not, and the sort by payer and reader is the thing that lasts.

The worked example is placed with its own report described, which is what a brand in the first business can do: {FL} has each batch tested by a contract laboratory for lead, mercury, arsenic and cadmium by inductively coupled plasma mass spectrometry against a specification, with the certificate for a given lot number released on request, and the laboratory named on it for a buyer to verify against the accreditation register; it is made in a UK facility certified to GMP and BRC, 1500mg magnesium bisglycinate stated as 300mg elemental at 80% NRV, two capsules with the evening meal, 180 capsules for £19.99 at 22p a day, and it is not enrolled in a certification programme, which a drug-tested athlete notes. The full label breakdown is here.

The verdict: the best supplement testing company in the UK depends on the question, because the testing market is three businesses sorted by who pays and who reads. For what is in this batch, a contract laboratory named on a certificate and verified in the accreditation register. For can I take this in a tested sport, a certification programme's public database. For what an independent party found at retail, a subscription service, if it has ever bought the product, which for UK brands it mostly has not.

What to check on the label

Questions people also ask

Who tests supplements in the UK?

Three different businesses that share a word: contract laboratories, paid by brands to test batches against a specification and reporting to the brand, judged by their accreditation for named methods; certification programmes, paid by brands to screen every lot for substances banned in sport and reporting to a public database by lot number; and subscription testing services, paid by consumers to buy products at retail and test them for label accuracy and contaminants, judged by their coverage, which is mostly American; a buyer uses each for a different question.

What is the difference between a testing lab and a certification programme?

Who reads the report: a contract laboratory tests a batch for assay, metals, microbes and the rest against the brand's specification and sends the report to the brand, which releases or rejects the batch and shows the buyer the certificate only if it chooses, while a certification programme screens every lot for banned substances and puts a pass or fail into a public database the buyer reads without asking anyone; the laboratory's report is the more detailed and the programme's is the more public, and they test for different things.

How do I find out which laboratory tested a supplement?

Email the brand with the lot number printed on the tub and ask for the certificate of analysis for that lot; a brand with the document sends it within days with the laboratory's name, the method and the result against the specification, and the laboratory is then checked in the UK accreditation service's public register, whose schedule lists the specific methods and sample types it is accredited for; a brand that replies with a general statement, a different lot or a redacted certificate has answered a different question.

Are the American supplement testing websites useful in the UK?

For American products, yes, because the subscription services buy products at retail and test them honestly for label accuracy and contaminants with the consumer as the client; for UK products, rarely, because the services test the products their subscribers ask about, which are the brands on American shelves, so a UK buyer searching for a UK product finds nothing, not because it failed but because it was never bought; the coverage limit is the thing to know before subscribing.

Which laboratory tests this site's magnesium?

A UK contract laboratory, named on the certificate of analysis that is released on request by lot number, which tests each batch for lead, mercury, arsenic and cadmium by inductively coupled plasma mass spectrometry against a specification, with the laboratory verifiable in the accreditation register; the product is made in a UK facility certified to GMP and BRC, states 300mg elemental at 80% NRV in two capsules with the evening meal, costs 22p a day, and is not enrolled in a sports certification programme, which a drug-tested athlete notes.

Sources

1. ISO/IEC 17025, the standard for testing and calibration laboratories: accreditation to it by a national body attests to a laboratory's technical competence and the validity of its results for the methods in scope, and is what makes a certificate of analysis a document someone has audited. https://www.ukas.com/accreditation/standards/laboratory-accreditation/
2. The UK Accreditation Service: UKAS accredits testing laboratories to ISO 17025 for defined scopes and publishes a searchable directory of accredited organisations and their schedules of accreditation. https://www.ukas.com/find-an-organisation/
3. The sports supplement certification programmes: Informed Sport, Informed Choice, BSCG and NSF Certified for Sport test products or batches for banned substances, the assurance competing athletes rely on. https://sport.wetestyoutrust.com/
4. The independent supplement testing services: subscription laboratories that purchase products at retail and test them for label accuracy, contaminants and disintegration, publishing pass and fail results by product, the one kind of review that reports what was in the tub rather than how it felt. PubMed record

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