About LabelTruth
How it works, and why you should not take our word for anything.
Last updated: 19 October 2026
The problem
For example: one label says “Magnesium Bisglycinate 500 mg”. That is the weight of the whole compound. The magnesium inside is about 70 mg — bisglycinate is roughly 14% magnesium by weight. Another label says “Magnesium 375 mg” and means the element itself. On a shelf the two numbers look comparable. They are not.
Nothing on either label tells you this. The information exists — it sits in chemistry tables, pharmacokinetic studies and EFSA opinions — but it is not where you are standing when you decide. That gap between what the seller knows and what you know is the whole reason this site exists.
What we do
Every product gets one number: the price of 1,000 mg of the element itself — for magnesium, 1,000 mg of magnesium, not of magnesium bisglycinate. Prices are normalised to EUR, so stores and currencies stay comparable.
It comes from three inputs:
- Price, traced to a specific page at a specific retailer.
- Dose per serving and servings per container, read from the product label.
- The share of the element in that chemical form — for example, about 14% for magnesium bisglycinate.
Where the human evidence for a chemical form is strong enough, we add a second number: PPAA — Price Per Absorbed Amount, the cost of the nutrient your body can actually take up. Where the evidence does not meet that bar, we do not show PPAA; the absorption research is still listed on the form's page with its source.
Where we cannot compute the price number honestly — no traceable price, unknown form, a blend — we still show the product and tell you why the number is missing.
The formula, every coefficient, and every threshold is published on the Methodology page. You can recompute any score on this site by hand and check us.
What we do not do
We do not review products. There are no star ratings and no editorial opinions about quality. We publish arithmetic.
We do not use judgement words. Our category labels refer to measured thresholds — “a product's unit price falls in a defined percentile of its comparison group (for example, ‘bottom third by unit price’)”, not “bad value”. If a claim cannot be stated as a number with a source, we do not publish it. That rule is why some labels here read awkwardly.
We do not give health advice. We compare value, not health outcomes. We cannot tell you whether you need a supplement, and we do not try. See our medical disclaimer.
We do not sell placement. No brand or retailer can pay to appear, rank higher, or have a figure removed. See our affiliate disclosure.
We do not hide products we score badly. A low score does not remove a product from the site. Transparency means showing you everything and letting you decide — that is the difference between an auditor and a censor. You may well have a good reason to buy a product we score poorly, and it is not our job to stop you. We show a purchase link only when the price can be traced to a specific page of a specific store; the listing and the arithmetic stay visible either way.
Why you should not trust a byline
Every absorption coefficient is cited to a published study, every threshold is documented, and the formula is public — so you never have to trust us. You can check the arithmetic yourself, and if it is wrong, the error is findable. A site that asked you to trust its author's expertise would be a weaker thing than one that shows its work.
How we make money
We may earn revenue through affiliate and partner agreements with retailers. The price you pay is unchanged, and no commission or partnership is an input to any score we publish — there is no field in our database where it could be. Full disclosure.
What we get wrong
This is a small operation working with messy public data. Known limits, stated plainly:
- Absorption coefficients describe populations, not you. They come from studies of groups. Your own absorption depends on your age, gut health, medication, and diet.
- Evidence differs by form. Some forms have human clinical studies, some only animal or mechanistic data, some none. We say which is which, and PPAA appears only for forms whose absorption has been measured in humans.
- Prices go stale. Each product page shows when its price was last confirmed. Always check at the retailer before buying.
- Labels get misread. Packages differ between countries, retailers restructure their sites, and our extraction is automated. Errors reach the catalogue.
- Coverage is still growing. We started with minerals and a few vitamins, where the arithmetic from label to element is settled. Botanicals, protein powders, probiotics and the rest are not analysed yet: each needs its own comparison basis before we can produce an honest number for it. The Elements page lists what is live and what is coming.
How to check us, and how to correct us
Every figure on this site is reproducible from the Methodology page. If you find an error, tell us at corrections@labeltruth.com with the product URL and the figure you dispute.
What happens next: we check the figure against its source. If we are wrong, we fix it within 14 days and record the correction publicly in our changelog, with credit to whoever found it. If the figure is correct, we reply with the source and the calculation, and it stays.
We do not remove accurate, sourced figures on request — including from the brands they concern.
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