What is the best third party supplement testing companies in the UK?

The schedule of accreditation: what it is, why accredited means only what it says, how a laboratory accredited for one matrix is not accredited for another, and the three steps to find and read it

What are the best third-party supplement testing companies in the UK is a question that is answered not by a list of names but by a document that ranks every name on any list, and the document is the schedule of accreditation. The UK accreditation service accredits laboratories to the international standard for testing laboratories, and accreditation is not a badge on the building: for each laboratory, the service publishes a schedule listing exactly which tests the laboratory is accredited to perform, by which method, on which kinds of sample, after an assessor has watched the laboratory run that method on that kind of sample and checked its validation, its equipment, its staff competence and its quality system for that specific combination. The word accredited on a certificate of analysis means what the schedule says and nothing more, and a buyer who reads the schedule knows more about the laboratory than any ranking could tell them.

The matrix is the part that catches people. A method is validated for a kind of sample, because the sample's composition affects how the analyte is extracted and measured, and the official methods for supplements are validated on supplement matrices for that reason. A laboratory accredited for heavy metals in drinking water by mass spectrometry has been assessed on water, and its schedule says so; it may be perfectly capable of running the same instrument on a ground capsule, and it may do so for a brand that asks, but that measurement is not within its accreditation, and the certificate, if it is honest, will say so with a note that the result is outside the scope of accreditation. A laboratory accredited for the assay of one vitamin by chromatography is not thereby accredited for the assay of another by a different method. A buyer who sees accredited laboratory on a brand's website and assumes it covers the test on the certificate has made the assumption the schedule exists to correct.

The schedule is found and read in three steps. First, the laboratory's name is taken from the certificate of analysis the brand sent, or from the brand's testing page if it names its laboratory, and searched in the accreditation service's public register, which returns the laboratory's accreditation number and a link to its schedule; a laboratory not in the register is not accredited by the service whatever its website says. Second, the schedule is opened, a document of a few pages listing tests in rows with the method and the sample type in columns. Third, the test on the certificate is found in the schedule by method and by a matrix that covers a food supplement, foods, or the specific product type; if it is there, the certificate's result carries the service's oversight, and if it is not, the result carries the laboratory's word, which may be good and is not the same thing.

A document that ranks laboratories by what they are actually accredited for, and the four things on a certificate checked against it, what accreditation does not cover, and the worked example with its laboratory's schedule described, which is the next section.

The four things on a certificate checked against the schedule, what accreditation does not cover and the questions it leaves to the buyer, the laboratories left unnamed because the register is the list, the worked example, and the verdict

Four things on a certificate of analysis are checked against the schedule, in order. The laboratory's name, which must match the register entry exactly, since laboratories trade under several names and a group may have accredited and unaccredited sites. The test, which must appear on the schedule as a named determination, heavy metals, a specific vitamin's assay, total viable count. The method, which must match the schedule's method for that test, since a laboratory accredited for metals by mass spectrometry is not accredited for metals by a cheaper technique it also offers. And the sample type, which must cover the product: food supplements, foods generally, or a matrix description that plainly includes a capsule, a tablet or a powder. A certificate that matches on all four is a measurement made under the service's oversight; a mismatch on any one means the result is the laboratory's own, and an honest laboratory marks such results on the certificate, so that an unmarked mismatch is itself a question for the brand.

What accreditation does not cover is worth stating so that the schedule is not asked to do more than it can. It covers the measurement: that the laboratory ran the stated method on the stated kind of sample competently and reported the result correctly. It does not cover whether the sample the brand sent was representative of the batch sold, or whether the brand sent the right tub at all; it does not cover whether the specification the result was compared with was a sensible one, since a brand sets its own limits and a generous limit is easily met; and it says nothing about whether the product works, which no laboratory measures. The buyer keeps those questions for the brand, by asking how samples are taken, by reading the specification's limits against the regulatory ones, and by reading the evidence for the product elsewhere, and uses the schedule for the one thing it settles, which is whether the number on the certificate is a number that can be relied on.

The laboratories are not named on this page, by rule and by reason: the register is the current, complete and official list of accredited UK laboratories and their schedules, it changes as accreditations are granted, extended and withdrawn, and a list of names on a page would be a worse version of it within a year. A buyer who wants the best third-party testing companies for supplements searches the register by the test they care about on a food supplement matrix and reads the schedules it returns, which takes ten minutes and produces a list no page could keep current.

The worked example is placed with its laboratory's schedule described: {FL} has each batch tested for lead, mercury, arsenic and cadmium at a UK contract laboratory whose schedule of accreditation lists heavy metals by inductively coupled plasma mass spectrometry on a food supplement matrix, so that the four things on its certificate, the name, the test, the method and the sample type, match the schedule, and the certificate is released by lot number on request for a buyer to run the three steps themselves; the product 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 is not in a sports certification programme. The full label breakdown is here.

The verdict: the best third-party supplement testing companies in the UK are ranked by their schedules of accreditation, not by their names, because accredited means only what the schedule says: the test, by the method, on the matrix. Find the laboratory on the certificate in the register, open its schedule, match the name, the test, the method and the sample type, and treat anything that does not match as the laboratory's word rather than the service's; then keep for the brand the questions the schedule cannot answer, how the sample was taken and whether the limits were sensible.

What to check on the label

Questions people also ask

How do I know if a supplement testing lab is properly accredited?

By reading its schedule of accreditation rather than its website: the UK accreditation service publishes, for every laboratory it accredits, a schedule listing exactly which tests the laboratory is accredited to run, by which method, on which kinds of sample, and the word accredited on a certificate means only what that schedule says; a buyer takes the laboratory's name from the certificate, finds it in the service's public register, opens the schedule and locates the test by method on a food or food supplement matrix, and a laboratory not in the register is not accredited whatever it claims.

Does an accredited lab mean every test it runs is accredited?

No; accreditation is granted per test, per method and per sample type after an assessor has watched that combination run and checked its validation, so a laboratory accredited for heavy metals in drinking water is not thereby accredited for heavy metals in a capsule, and one accredited for a vitamin's assay by one method is not accredited for a different vitamin by a different method; an honest laboratory marks results outside its scope on the certificate, and an unmarked mismatch between the certificate and the schedule is a question for the brand.

What does lab accreditation not tell me about a supplement?

Anything beyond the measurement: it covers that the laboratory ran the stated method on the stated kind of sample competently and reported correctly, and it does not cover whether the sample the brand sent was representative of the batch sold or was the right tub at all, whether the specification the result was compared with was a sensible one, since a brand sets its own limits and a generous limit is easily met, or whether the product works, which no laboratory measures; those questions stay with the brand and the evidence.

Which UK labs test supplements?

The accreditation service's register is the current, complete and official list and a page cannot keep up with it: accreditations are granted, extended and withdrawn, so a buyer searches the register by the test they care about on a food supplement matrix, reads the schedules it returns and has, in ten minutes, a list of every UK laboratory accredited for that test on that kind of sample, which is the only ranking of third-party testing companies that means anything.

Is this site's magnesium tested by an accredited laboratory?

Yes, within scope: each batch is tested for lead, mercury, arsenic and cadmium at a UK contract laboratory whose schedule of accreditation lists heavy metals by inductively coupled plasma mass spectrometry on a food supplement matrix, so that the laboratory's name, the test, the method and the sample type on the certificate all match the schedule, and the certificate is released by lot number on request for a buyer to check themselves; the product is 300mg elemental at 80% NRV in two capsules with the evening meal, UK made under GMP and BRC, at 22p a day.

Sources

1. The UK accreditation service's schedules of accreditation: each accredited laboratory holds a published schedule listing the specific tests, methods and sample types it is accredited for, searchable by laboratory name, so that accredited is a statement about named methods on named matrices rather than about the laboratory as a whole. https://www.ukas.com/find-an-organisation/
2. 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/
3. The official methods of analysis for dietary supplements: validated methods for the identity and quantity of vitamins, minerals, botanical markers and contaminants in supplement matrices, with the method's validation covering the sample type, which is why a laboratory names the method and the matrix on its report. https://www.aoac.org/official-methods-of-analysis/
4. The Informed programmes' operator: Informed Sport and Informed Choice are run by LGC, an accredited laboratory group whose sports-supplement testing operates under ISO 17025 laboratory accreditation, with certified products and batches published on a public database. https://sport.wetestyoutrust.com/about

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