A Supplement Facts panel tells you three things reliably: what a brand calls one serving, how many of those servings are in the package, and what ingredients are in it in descending order by weight. It does not tell you how much of each ingredient is in a proprietary blend, and it does not tell you what is actually in the product — only what the brand says should be. Learning to read the panel takes about five minutes and it stops most bad purchases before they happen.
This guide covers the three fields that get misread most often — serving size, servings per container, and proprietary blends — plus a simple arithmetic check that catches labels whose numbers cannot physically be true.
Quick answer: what each line does and does not tell you
| Panel line | What it tells you | What it hides |
|---|---|---|
| Serving Size | The unit the brand chose for every number below it | Whether that unit matches how anyone actually uses the product |
| Servings Per Container | How many of those units the package holds | Nothing, but it is the number that converts price into cost per serving |
| Amount Per Serving | Milligrams of each named ingredient | Nothing — this is the most honest line on the panel |
| Proprietary Blend | Total blend weight, plus the ingredients ranked by weight | Every individual amount inside the blend |
| % Daily Value | How a nutrient compares to an established reference intake | Nothing useful for botanicals, which mostly have no established value |
| Other Ingredients | Excipients, flavours, sweeteners and colours, by descending weight | Their amounts |
What "serving size" actually commits a brand to
For dietary supplements, the manufacturer sets the serving size — it is meant to reflect the amount customarily consumed, but there is no regulator assigning one. That makes serving size the single most manipulable field on the panel, because every milligram figure underneath it is expressed in those units.
The most common move is the fractional unit. A scored tablet is sold as a three-tablet pack, and the panel declares a serving of half a tablet. That is legitimate if the tablet is genuinely designed to be halved. It also quietly halves every number the buyer sees, and it doubles the servings-per-container figure on the front of the box. Two products with identical contents can look very different depending on whether the brand picked a half tablet, a whole tablet, or a whole pack.
The practical fix is to convert everything to one unit before comparing anything. Pick a unit you would actually consume — one tablet, one sachet, one shot — and restate every product in those terms. Formats differ enough that this matters: put the tablets and the sachets into the same units before deciding either one is better value.
Servings per container, and the arithmetic that changes the price
Servings per container is the least interesting number on the panel and the most useful one for shopping. It converts a shelf price into a cost per serving, which is the only figure that compares across formats.
Take a three-count blister of scored tablets, 200 mg of blend per tablet, sold with a panel that declares six half-tablet servings. At a shelf price of $18 that is $3.00 per declared serving and $6.00 per tablet. A competing sachet at $7 each with one sachet per serving is more expensive per serving than the tablet even though the sticker price is lower. Neither of those facts is visible on the front of a box.
Do the division before you compare. It also protects you from the reverse trick: a large servings-per-container number produced entirely by shrinking the serving.
Why proprietary blends hide composition
A proprietary blend lets a brand declare a group of ingredients as a single total weight instead of listing each amount. The rules require two things: the total weight of the blend, and the ingredients listed inside it in descending order of predominance by weight. That is all.
Consider a 600 mg blend containing six botanicals. The label is complete and lawful if it prints "Proprietary Blend 600 mg" followed by the six names. Inside that 600 mg, the first-listed ingredient could be 595 mg and the last-listed 1 mg, or the split could be even. Both are consistent with the same label. Descending order is the only information you get, and it only tells you rank, never distance.
This matters most when the blend is named after the plant on the front of the box. A blend called for a botanical does not tell you how much of that botanical is in it — the name is marketing copy, and the position of that ingredient in the list is the only real signal. If the headline botanical appears last in a six-item blend, it is the smallest component by weight.
Blends are not automatically dishonest. There are real formulation reasons to keep a ratio private. But you should price a blend as an unknown, not as the amount the front of the package implies, and you should notice that a blend is precisely the structure that makes a composition claim unverifiable from the label alone.
How to check whether a label's math is physically possible
Here is a check almost nobody runs, using a real example from a product we evaluated and did not list.
The published panel declared, per half-tablet serving: 100 mg of a proprietary extract, 200 mg quercetin, 150 mg L-theanine, 200 mg urolithin A, 60 mg ascorbic acid and 10 mg pyridoxine HCl. That sums to 720 mg per half tablet, so 1,440 mg per tablet. The brand's own certificate of analysis recorded the measured unit weight of that tablet as 780.9 mg.
You cannot fit 1,440 mg of ingredients into a 781 mg tablet. The most likely explanation is benign: the amounts are per tablet rather than per half tablet, and the serving heading is wrong — 720 mg of ingredients inside a 780.9 mg tablet reconciles neatly, leaving room for binders. But "the label is off by a factor of two in the direction that flatters it" is a defect either way, and a retailer that copies channel copy verbatim inherits it.
The check itself is simple:
- Add every declared amount per serving, including the proprietary blend total.
- Multiply up to a whole unit if the serving is a fraction.
- Compare that to the unit weight — printed on some certificates, or estimated from net weight divided by count.
- Leave room for excipients. A tablet is never one hundred percent declared ingredient; binders, flow agents and coatings take real mass.
- If the declared amounts exceed the unit weight, the label is wrong. Ask which number is the error.
The "Other Ingredients" line is not filler text
Below the panel sits a line of excipients: things like microcrystalline cellulose, dicalcium phosphate, silicon dioxide, magnesium stearate, sweeteners such as sucralose, and food-grade colourants. These are listed by descending weight with no amounts.
Read it for three reasons. It is where allergens and animal-derived ingredients appear, such as gelatin in a softgel. It is where sweeteners appear, which matters if you avoid them. And a very long list on a small tablet tells you the declared fraction is smaller than the front of the box suggests.
What the panel cannot tell you at all
A Supplement Facts panel is a declaration of intended composition. It is written by the brand, printed before the batch ships, and describes what is supposed to be in the product. It is not a measurement.
That gap is the reason certificates exist. A label cannot report an undisclosed ingredient, because a brand that intended to disclose it would have put it on the label. Only testing can speak to what is actually present, and only for the compounds the panel of analytes covers — which is its own limitation, and the reason we published nine red flags on a certificate of analysis. The certificates we hold are on our COA page, with their gaps described rather than smoothed over, and where we hold none for a brand the page says that too.
Read the label and the certificate together. The label tells you the claim; the certificate tells you whether anyone checked it.
A five-minute label check
- Find the serving size and convert it to a whole unit you would actually use.
- Divide the price by servings per container, then by units, so you have both numbers.
- Look for a proprietary blend. If there is one, note the total weight and where the headline ingredient sits in the order.
- Sum the declared amounts and sanity-check them against the plausible mass of the unit.
- Read Other Ingredients for allergens and sweeteners.
- Find the batch number on the package and match it to a published certificate.
- Check the label carries a manufacturer or distributor name and a physical address. A supplement label without one is missing a legally required field.
If any step stalls because the information is not published, that is the finding. You can browse what we carry in the Cat's Claw collection, and general questions are answered on our FAQ page.
Frequently Asked Questions
Does a bigger milligram number mean more of the named ingredient?
Not on its own. A milligram figure describes the mass of material, not its concentration or composition — 600 mg of a blend and 600 mg of a single standardised extract are not comparable quantities. And if the number sits inside a proprietary blend, it describes the whole blend rather than any one component.
Why do so many botanical products have no % Daily Value?
Because Daily Values exist only for nutrients with an established reference intake, such as vitamin C or B6. Botanical ingredients generally have none, so the panel prints a dagger symbol and a footnote saying Daily Value not established. It is normal and it is not a quality signal in either direction.
Is a proprietary blend a reason not to buy?
Not by itself, but it is a reason to discount the specificity of everything the marketing says. If a brand's whole pitch rests on one ingredient and that ingredient is buried inside an undisclosed blend, the pitch is not verifiable from the label. Weigh that against how much the brand publishes elsewhere.
Should the label match the certificate exactly?
They answer different questions, so they will not read identically, but they must not contradict each other. A label naming an ingredient the certificate reports as non-detect is a contradiction worth raising with the seller, and it is one of the things we look at before agreeing to carry anything — the buyer-side version of the same checklist is in how to buy botanical products safely online.
What serving size should I use?
Follow the label of the specific product and do not exceed the labelled serving. We are not going to suggest a number of our own, and you should treat any seller who encourages you to exceed the labelled serving as a seller to avoid. These are adults-only products and the labelled serving is the manufacturer's own stated limit.
These statements have not been evaluated by the U.S. Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. For adults 21+. Legality depends on the specific formulation and applicable state law — check the rules where you live. Nothing here is legal advice.