What is the best 3rd party supplement testing companies in the UK?

The test menu: what a UK contract laboratory will run on one tub for a member of the public, what each line measures, and what each costs

What are the best third-party supplement testing companies in the UK is a question most people ask hoping for a name, and the more useful answer is that the companies are not a secret and will work for the buyer directly: a UK contract laboratory, the kind that tests batches for brands, will test one tub for a member of the public as readily as a thousand for a manufacturer, at a published price per test, and a buyer with a real doubt about a product can settle it for the cost of a few months' supply rather than trusting a page or a brand. The thing to know first is the menu, because a laboratory does not test a supplement for quality, it runs specific tests that a buyer orders by name, and the menu for a supplement is short.

The first line is identity and assay: does the tub contain the active ingredient it names, and how much per capsule against the label figure. For a vitamin or a mineral this is a validated method, a chromatographic assay for the vitamin or an elemental analysis for the mineral, reported as a quantity per capsule that the buyer compares with the label within the tolerances; for a botanical it is an assay of a marker compound, which tells the buyer the extract is what it claims and says less about potency. The second line is heavy metals: lead, mercury, arsenic and cadmium by inductively coupled plasma mass spectrometry, reported in parts per million or per billion against limits, the test most often commissioned because metals are the contaminant a buyer cannot see, taste or feel and the one that accumulates. The third is microbiology: total viable counts, yeasts and moulds, and named pathogens, by culture, reported in colony-forming units per gram against limits. The fourth is disintegration: whether the capsule or tablet breaks apart in a standard apparatus within a standard time, which is the test that catches a tablet pressed so hard it passes through a person intact. The fifth, for botanicals, is residues: pesticides by a multi-residue screen and residual solvents from the extraction, both reported against limits. There is a sixth line, a screen for substances banned in sport, that a few laboratories offer to individuals and that is usually better obtained through a certification programme's database for an enrolled product.

Each line has a price, and the prices are the reason this page exists. At a UK contract laboratory the metals panel on one sample runs to tens of pounds, an assay for a single vitamin or mineral to tens or low hundreds depending on the method, a microbiological panel to tens, a disintegration test to tens, and a pesticide multi-residue screen to a few hundred, with a set-up or sample handling charge on top; the whole menu on one tub costs roughly what a few months of a premium supplement costs, and a single line, metals or assay, costs less than a tub of many premium products. A buyer who has read a forum thread claiming a product is underdosed or contaminated can find out for the price of the product, and the finding is theirs to publish, which is a thing the brand knows.

A menu with five lines and a price on each, and how to choose the laboratory, how to submit a sample so the result means something, what the report will and will not say, and the worked example, which is the next section.

Choosing the laboratory from the accreditation register by the method on its schedule, submitting a sample so the result means something, what the report will and will not say, the brands left unnamed, the worked example, and the verdict

The laboratory is chosen from the accreditation register, not from a search engine, and chosen by method. The UK accreditation service publishes a schedule for every laboratory it accredits, listing the specific tests, the methods and the sample types the laboratory is accredited for, and the right laboratory for a given line of the menu is one whose schedule names that test on a food supplement or food matrix, because accreditation is a statement about a named method on a named sample type and not about the laboratory as a whole; a laboratory accredited for metals in water is not thereby accredited for metals in capsules, and a buyer who checks the schedule before commissioning gets a result that carries the accreditation's weight. The register is searched by test and by sample type, it returns the laboratories accredited for that combination, and a buyer contacts two or three for a price and a turnaround, which is usually a couple of weeks. The laboratories that serve the supplement industry are used to enquiries from brands and will treat an individual's single sample as a small job, which it is.

The sample is submitted so the result means something, and the rules are simple. One unopened unit, bought by the buyer from the channel they are worried about, with its lot number and expiry recorded and the seal intact, so that the result describes the product as sold rather than a tub that has been opened, stored in a hot car or tampered with; the laboratory will usually ask for a minimum quantity, a certain number of capsules or grams, and a tub of a normal size covers it. The buyer states the label claim per capsule for an assay so that the laboratory reports against it, and asks for the result on the certificate to be expressed per capsule rather than per gram of powder, which saves a conversion. A second unit from a different lot, or from the brand's own site, tested alongside, turns a single result into a comparison, which is worth the second fee if the first result is the point of a dispute.

What the report will say is a number against a limit or a label claim for each line ordered, with the method and the laboratory's accreditation stated, and that is all it will say: it will not say whether the product is good, whether it works, whether the dose is right for the buyer, or anything about lines that were not ordered. A metals pass says nothing about the assay and an assay pass says nothing about microbes, and a buyer who wants the whole picture orders the whole menu. The laboratories are not named on this page, by rule, because the register is the current list and a page is not, and because the right laboratory is the one whose schedule carries the test the buyer wants, which the register finds in a minute.

The worked example is placed with the menu run on it, which is what a brand in this business does before a buyer has to: {FL} has the metals line, lead, mercury, arsenic and cadmium by mass spectrometry, run on every batch by a UK contract laboratory against a specification, with the certificate released by lot number on request, and the assay implied by the label, 1500mg magnesium bisglycinate stated as 300mg elemental at 80% NRV, released against specification in a UK facility certified to GMP and BRC, two capsules with the evening meal, 180 capsules for £19.99 at 22p a day; a buyer who commissions their own metals test on a tub has the brand's certificate to compare it with, which is the comparison the page recommends. The full label breakdown is here.

The verdict: the best third-party supplement testing companies in the UK are the contract laboratories on the accreditation register whose schedules carry the test a buyer wants on a supplement matrix, and they will run it for a member of the public at a price from tens to a few hundred pounds per line. Order from the menu by name, submit one sealed unit with its lot number, read the number against the limit or the label, and remember that the report says only what was ordered.

What to check on the label

Questions people also ask

Can I get a supplement tested myself in the UK?

Yes; a UK contract laboratory will test one tub for a member of the public at a published price per test, and the menu is short: identity and assay of the active against the label, lead, mercury, arsenic and cadmium by mass spectrometry, microbial counts, disintegration of the capsule, and for a botanical, pesticide residues and solvents, each from tens to a few hundred pounds per sample; the laboratory is chosen from the accreditation register by the method on its schedule, one sealed unit with its lot number is submitted, and the result comes back in a couple of weeks.

How much does it cost to test a supplement for heavy metals?

Tens of pounds per sample at a UK contract laboratory for the four-metal panel, lead, mercury, arsenic and cadmium, by inductively coupled plasma mass spectrometry, plus a set-up or handling charge, reported in parts per million or billion against limits; it is the most commonly commissioned line on the menu because metals are the contaminant a buyer cannot see, taste or feel and the one that accumulates, and a single metals test costs less than a tub of many premium products, which is the arithmetic that makes commissioning worth it when a doubt is real.

How do I choose a lab to test a supplement?

By the method on its accreditation schedule: the UK accreditation service publishes a schedule for every laboratory it accredits listing the specific tests, methods and sample types, and the right laboratory for a given test is one whose schedule names it on a food supplement or food matrix, because a laboratory accredited for metals in water is not thereby accredited for metals in capsules; the register is searched by test and sample type, two or three laboratories are asked for a price and turnaround, and the result then carries the accreditation's weight.

What will a supplement test report tell me?

A number against a limit or a label claim for each line ordered, with the method and the accreditation stated, and nothing else: it will not say whether the product is good, whether it works or whether the dose suits the buyer, and it says nothing about lines not ordered, so a metals pass says nothing about the assay and an assay pass nothing about microbes; a buyer who wants the whole picture orders the whole menu, and a second unit from another lot or from the brand's own site tested alongside turns a single result into a comparison.

Has this site's magnesium been tested by a laboratory?

Yes, on the metals line on every batch: lead, mercury, arsenic and cadmium by mass spectrometry at a UK contract laboratory against a specification, with the certificate released by lot number on request, and the assay implied by the label, 1500mg magnesium bisglycinate stated as 300mg elemental at 80% NRV, released against specification in a UK facility certified to GMP and BRC; a buyer who commissions their own metals test on a tub has the brand's certificate to compare it with, which is the comparison the page recommends, at 22p a day for the product.

Sources

1. 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/
2. The heavy metals analysis literature: inductively coupled plasma mass spectrometry is the standard method for quantifying lead, cadmium, mercury and arsenic in dietary supplements against regulatory maximum levels. PubMed record
3. 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/
4. The pharmacopoeial disintegration test: uncoated tablets and hard capsules are required to disintegrate in warm aqueous medium within a set time, typically 30 minutes for uncoated tablets and shorter for capsules, the test a tablet pressed too hard to dissolve fails and a kitchen glass of warm water crudely imitates. PubMed record

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