How do I find high quality supplements?

Start from the register, not the shelf: why the order of the search decides who sorts the results, and the first two steps, the register entry that fixes the dose and the evidence that fixes the form

How do I find high quality supplements is a question about a search, and the answer depends on where the search starts, because whoever controls the starting point sorts the results. A buyer who starts at the shelf, or at a marketplace's search box with a nutrient's name, is handed hundreds of products sorted by the marketing: the sponsored listings, the words premium and pure and high strength, the star averages and the packaging, none of which is a quality signal and all of which is designed to be the first thing seen. A buyer who starts at the health claims register, the public list of what a nutrient may lawfully claim and at what intake, has fixed the two things that matter most before a single product is seen, and arrives at the shelf with a specification rather than a hope. The strategy runs in four steps in a fixed order, and the first two happen before the shop is opened.

The first step is the register entry for the nutrient. The buyer searches the Great Britain register for the nutrient they want, reads the authorised claims in their fixed wording, and reads the conditions of use, which state the intake at which the claim may be made, usually a stated fraction of the nutrient reference value per daily portion; that intake is the dose that earns the claim, and it becomes the dose the buyer searches for. For magnesium the register lists normal muscle function, normal protein synthesis, electrolyte balance, normal energy-yielding metabolism, normal psychological function, normal nervous system function and the reduction of tiredness and fatigue, conditioned on a product providing a meaningful share of the reference value, which for a daily dose points the buyer at a few hundred milligrams of elemental magnesium rather than at a compound weight or at a high-strength figure above the upper level. The dose is now fixed, and it was fixed by the regulator rather than by a brand.

The second step is the form, and it is fixed by the absorption and tolerance evidence for that nutrient rather than by the shelf's words. For magnesium the bisglycinate is absorbed as well as or better than the oxide and is far less likely to produce loose stools at a useful dose, so the form is the bisglycinate; for vitamin D it is D3; for iron the bisglycinate over the sulphate for tolerance; for B12 the cyanocobalamin for most people and the methyl form for the few who absorb it poorly; for creatine the monohydrate, which every trial used. The form is now fixed, and with it the ingredient list the buyer is looking for, which for a mineral is the form of the active, a capsule shell and one flow agent, and nothing for appearance. A buyer with a dose and a form has a specification, and the shop is opened only now.

Two steps that fix the dose and the form before the shop is opened, and the two that follow, the search by dose and form that produces a short list and the three documents that sort it, with the words typed and not typed and the worked example found, which is the next section.

The third step, a search by elemental dose and form that produces a short list, with the words that are typed and the words that are not; the fourth step, the three documents that sort the short list; the worked example found; and the verdict

The third step is the search itself, and the words typed are the specification rather than the shelf's vocabulary. On a UK marketplace or a retailer's site the buyer types the form and the elemental dose, magnesium bisglycinate 300mg elemental, vitamin D3 1000 IU, creatine monohydrate, and reads the results for the products whose labels match, which is a handful rather than hundreds, because most products on the shelf use the cheap form, state the compound weight or sit at a different dose. The words not typed are the ones that return the marketing: premium, pure, clean, high strength, best, pharmaceutical grade, and the brand names a buyer has heard of, each of which sorts the results by who paid for the word rather than by what is in the capsule. The sponsored listings at the top of any search are skipped, since a sponsored position is a payment and not a signal, and the short list is read from the labels, with the ingredient list checked against the form and the nutrition panel checked for the elemental dose with its reference value percentage. A product whose label states the compound weight without the elemental figure is removed from the short list for that reason, because the second formulation decision was made for the shelf.

The fourth step sorts the short list with three documents, and it is the only step that needs an email. The certificate of analysis by lot, requested from each short-listed brand with a lot number or for the most recent batch, naming the laboratory and the tests, which a brand with release testing sends within days and a brand without cannot. The facility's named standard, good manufacturing practice certification and, for many UK facilities, the retail consortium's standard, stated on the brand's site and verifiable with the certifier. And the operator's address, a UK or EU food business operator on the label, checkable in the company register for a trading history. The short list is ranked by how many of the three each product can show, a product with all three outranks a product with two whatever its price, and two products with all three are compared on price per day at the elemental dose, which is the last thing the buyer looks at and the first thing the shelf shows. Sponsored position, star average and brand recognition are not in the ranking, because none is a document.

The strategy's property is that it is the same for every nutrient and that the buyer, not the shelf, holds every step. The register fixes the dose, the evidence fixes the form, the search by dose and form fixes the short list, and the documents fix the order; a buyer who has run it once for a mineral can run it in ten minutes for a vitamin, and the brands that rise to the top are the ones whose label decisions were made for the person and whose documents exist, which is the definition of high quality this site uses throughout.

The worked example is found by the strategy rather than placed by the page: a search for magnesium bisglycinate at 300mg elemental on a UK marketplace returns {FL} among a handful, its label stating 1500mg magnesium bisglycinate as 300mg elemental at 80% NRV, the intake its register claims are conditioned on, with three ingredients, the bisglycinate, an HPMC capsule and rice flour; and the three documents sort it to the top of its short list, a certificate of analysis for lead, mercury, arsenic and cadmium by lot on request from an accredited UK laboratory, a UK facility certified to GMP and BRC, and a UK operator's address with a UK company on the register; two capsules with the evening meal, 180 capsules for £19.99 at 22p a day, which is the price per day read last. The full label breakdown is here.

The verdict: find high quality supplements by searching from the register rather than from the shelf. Fix the dose from the nutrient's authorised claim and its conditioned intake, fix the form from the absorption and tolerance evidence, search a UK marketplace or retailer by the elemental dose and the form rather than by a brand or a word like premium, and sort the handful that match by the certificate by lot, the facility's named standard and the operator's address, with price per day read last. The buyer holds every step, and the marketing holds none.

What to check on the label

Questions people also ask

What is the best way to search for a good quality supplement?

From the register rather than the shelf, in four steps: read the nutrient's authorised claims on the Great Britain register and the intake they are conditioned on, which fixes the dose; fix the form from the absorption and tolerance evidence for that nutrient; search a UK marketplace or retailer by the form and the elemental dose, typing magnesium bisglycinate 300mg elemental rather than premium or a brand name and skipping the sponsored listings, which produces a handful of matching products; and sort them by the certificate by lot, the facility's named standard and the operator's address, with price per day read last.

What search terms should I avoid when buying supplements?

The shelf's vocabulary, because each word sorts the results by who paid for it rather than by what is in the capsule: premium, pure, clean, high strength, best, pharmaceutical grade, and the brand names a buyer has heard of; the words to type instead are the specification the register and the evidence fixed, the form and the elemental dose, which return the products whose labels match and exclude the hundreds that use the cheap form, state the compound weight or sit at a different dose; sponsored listings are skipped because a sponsored position is a payment and not a signal.

How do I know what dose of a supplement to look for?

From the health claims register rather than the label: each authorised claim for a nutrient is granted with conditions of use that state the intake at which the claim may be made, usually a stated fraction of the nutrient reference value per daily portion, and that intake is the dose that earns the claim and the dose to search for, stated as elemental content with its reference value percentage; a product far above it is a number chosen to look large, often near the upper level, and a product below it cannot lawfully make the claim it implies, and a label that states compound weight without the elemental figure is removed from the short list.

Which documents sort a short list of supplements?

Three, and the only step that needs an email: the certificate of analysis by lot, requested from each brand with a lot number or for the most recent batch, naming the laboratory and the tests, which a brand with release testing sends within days; the facility's named standard, good manufacturing practice and for many UK facilities the retail consortium's standard, stated on the brand's site and verifiable with the certifier; and the operator's UK or EU address on the label, checkable in the company register; a product with all three outranks one with two whatever its price, and price per day at the elemental dose breaks the tie.

Would the search strategy find this site's magnesium?

Yes, by the specification rather than by the name: a search for magnesium bisglycinate at 300mg elemental on a UK marketplace returns it among a handful, with its label stating 1500mg magnesium bisglycinate as 300mg elemental at 80% NRV, the intake its register claims are conditioned on, and three ingredients, and the three documents sort it to the top of its short list, a four-metal certificate by lot on request from an accredited UK laboratory, a UK facility certified to GMP and BRC, and a UK operator's address with a UK company on the register, at 22p a day read last.

Sources

1. Retained Regulation (EC) No 1924/2006 on nutrition and health claims made on foods, and the Great Britain nutrition and health claims register. https://www.gov.uk/government/publications/great-britain-nutrition-and-health-claims-nhc-register
2. The retained Food Information to Consumers regulation: the mandatory nutrition declaration for foods, its fixed order of energy, fat, saturates, carbohydrate, sugars, protein and salt per 100g, and its rules on portion information, with supplements declaring nutrients per daily dose against nutrient reference values. https://www.legislation.gov.uk/eur/2011/1169/contents
3. 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
4. Companies House: the UK's public register of companies, searchable free by name or number, showing registered office, incorporation date, officers and filed accounts. https://find-and-update.company-information.service.gov.uk/

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