Panel guide
How to read a Supplement Facts panel
Three things on a Supplement Facts panel decide whether any number on it means anything: the standardisation, the extract ratio, and the percent Daily Value. This guide explains all three, using the product this site sells as the worked example.
A standardisation names the compound the research measures and states what proportion of an extract is that compound — the only figure that lets a bottle be compared with a study. An extract ratio describes a manufacturing step, not a potency. A percent Daily Value is only as good as the Daily Value it was calculated against, and those change.
Standardisation: the figure that matters
Most supplement labels give you a plant and a weight. “Turmeric extract, 500 mg”. That tells you how much powder is in the capsule and nothing about what is in the powder.
A standardisation closes the gap. “Turmeric extract, 500 mg, standardised to 95% curcumin” tells you there are 475 mg of curcumin — the compound the trials measure — in a serving. You can now find what a study used and divide, which is the entire exercise.
| Ingredient | Marker compound | Typical standardisation where declared |
|---|---|---|
| Turmeric | Curcumin / curcuminoids | 95% |
| Konjac | Glucomannan | 90-95% |
| Resveratrol | trans-resveratrol | 20-98% |
| Green tea | EGCG | 45-98% |
| Berberine | Berberine HCl by assay | usually sold as the salt |
| Cinnamon | Not commonly standardised | — |
| Mangosteen | Alpha-mangostin, where declared | — |
Standardisation is rare on labels for three reasons: it costs money, because it means testing every batch of raw material and rejecting the ones that miss; it creates liability, because a number on a label is a number that can be tested; and it is not required by law. A fourth reason is the uncomfortable one — “10:1” is more persuasive to a shopper than “95% curcumin”, and costs nothing to print.
Extract ratios: what 10:1 does and does not mean
When a label says 10:1, ten parts of the starting plant were processed down to one part of finished extract. A 4:1 is four to one, a 100:1 is a hundred to one. It is a manufacturing statistic: a record of how much water, fibre and inert plant matter was removed.
That is genuinely useful. It tells you the material is concentrated rather than ground leaf, and it lets you compare two products of the same herb if both print a ratio. Most labels print neither.
What the ratio cannot tell you is what came through the process. Extraction is selective by design: a water extract and an ethanol extract of the same plant at the same ratio contain different compounds in different proportions. Two 10:1 extracts of the same bark, from different manufacturers, can differ several-fold in whatever you care about.
The trap is the dry-powder equivalent. “100 mg of a 10:1 extract, equivalent to 1,000 mg of raw bark” is arithmetically true and reads as though the capsule contains a gram of something. The capsule contains a hundred milligrams. The equivalence is by weight of starting material, not by effect.
Percent Daily Values, and why they go stale
A percent Daily Value is the one number on a supplement panel that looks official, and it is worth knowing exactly what it is.
The FDA defines Daily Values as “the recommended amounts of nutrients to consume or not to exceed each day”, and publishes a table of them. A panel divides the amount in a serving by the Daily Value and prints the percentage. Only nutrients with an established Daily Value get one; everything else carries a dagger and a footnote saying “Daily Value not established”.
The catch is that the table changes. The FDA overhauled it as part of the 2016 Nutrition and Supplement Facts labelling rules, and several values moved. Riboflavin went from 1.7 mg to 1.3 mg. Vitamin D changed unit. Others shifted too.
So a percentage on a panel can be arithmetically correct against a table that no longer applies. The way to check takes ten seconds: divide the amount by the current Daily Value yourself and see whether you get the printed figure.
Why an out-of-date percentage is not a safety problem
It almost never is. A stale Daily Value makes a number look smaller or larger than it should, but the amount in the capsule is whatever the panel says it is. What it tells you is about the label rather than the product: that the artwork has not been revised recently, or was copied from an older template.
Worked example: this product’s panel
It would be dishonest to write this guide and not apply it here. Trimoryn’s panel is the best worked example this desk has, because it contains all three cases.
| Row | What kind of figure | What it lets you do |
|---|---|---|
| Konjac 50 mg, Std. 90% Glucomannan | Standardisation | Work out 45 mg, and compare it with the 1.24-3.99 g the NIH trials used |
| Turmeric 15 mg, Std. 95% Curcumin | Standardisation | Work out about 14 mg, and compare it with trials in hundreds of mg |
| Resveratrol 12 mg, Std. 20% | Standardisation | Work out about 2.4 mg, against the 1 g/day MSK records |
| Prickly pear 100 mg, 4:1 | Extract ratio | Know it is concentrated. Nothing more |
| Cinnamon 100 mg, 10:1 | Extract ratio | Know it is concentrated. Nothing more — and the species is not named |
| Riboflavin 25 mg, 1470% | Percent Daily Value | Check it: 25 ÷ 1.3 = 1,923%. The printed figure uses the old 1.7 mg value |
| Mangosteen 100 mg | Neither | Know the weight of powder, and nothing about its content |
| Berberine 15 mg | Neither needed | Berberine HCl is a defined compound, so the weight is the amount |
Three standardisations, two ratios, one stale percentage and one row with nothing at all. Every criticism on this site rests on the first three — which means the manufacturer supplied the rope. That is worth crediting, and it is why this desk scores label transparency 4 out of 5 on a product it scores 1 for claim accuracy.
The five-second test
Applicable to anything on any shelf, including this one.
- Cover the front of the package. Read only the Supplement Facts panel.
- Find the standardisations. If there are none, you cannot compare this product with any study, and neither can the person selling it to you.
- Do one division. Pick the ingredient you most want to work, find the studied dose, divide. This is the step that answers the question.
- Check any percentage. Divide the amount by the current Daily Value. If you do not get the printed number, the artwork is out of date.
- Then uncover the front. If it makes you expect more than the panel did, the difference is the marketing, and the marketing is the part nobody has substantiated.
On this product the test comes out unusually well in step two and badly in step three, which is the summary of the whole site in one sentence: a better panel than the category deserves, attached to amounts the panel itself shows are too small.
Two more things on a panel worth checking
Standardisation, ratios and Daily Values are the three that decide whether a number means anything. Two smaller checks catch most of the remaining errors.
The plant part
Root, leaf, bark, berry, seed. Research on one part frequently does not transfer to another, and labels get this wrong often enough to be worth ten seconds. A nettle root study says nothing about nettle leaf; a cinnamon bark extract is not a cinnamon leaf extract.
The species
Where a common name covers several species, the Latin name is the only way to tell which is in the bottle. Cassia and Ceylon cinnamon differ enormously in coumarin. Panax ginseng and American ginseng have different research files. If the Latin name is missing, the row is less informative than it looks.
On this product the plant parts are stated clearly — berry, root, bark, where relevant — and the species is not, on the one row where it matters most. That asymmetry is the sort of thing a careful panel check turns up and a glance does not.
Read the panel first, then decide
Thirty capsules, one a day, eleven rows itemised and five of them standardised — the best-disclosed label this desk has read. It is also a label whose two best-studied weight ingredients sit at a fraction of the amounts the research used. The live price and the 60-day return terms are both on the seller’s checkout screen.
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