How to Read a Supplement Label in Sixty Seconds

Read the Supplement Facts panel on the back, in this order: the serving size, then the amount per serving, then the % Daily Value column including its blanks, then the ingredient list underneath the box. The front of a container is a design decision. The panel behind it has a format fixed by 21 CFR 101.36, and once you know what each line is obliged to say, you also know what it is permitted to leave out.

What follows is the panel line by line; the three parts of it that almost nothing on the shelf explains — the blank % Daily Value column, the "Other ingredients" list, and the flow agents inside it; and then six checks that settle most of a label in about a minute.

This page is a hub. Where a question has a page of its own on this site, it gets a sentence here and a link there rather than a worse second version.

What is on a Supplement Facts panel?

A serving size, a servings-per-container figure, the heading "Amount Per Serving", the name and quantity by weight of every dietary ingredient, and a % Daily Value wherever one has been established. Ingredients with no established Daily Value carry a symbol instead of a number, keyed to a footnote at the foot of the box that reads "Daily Value not established". Anything in the container that is not a dietary ingredient — binders, flow agents, capsule shells, flavourings — sits below the box under "Other ingredients".

That order is not a house style. It is the form set out at 21 CFR 101.36, and the useful consequence is that a panel is a form with fields. So the interesting question is never only what a field says. It is which fields the rule lets a brand leave empty, and what an empty one means.

What is the difference between Supplement Facts and Nutrition Facts?

The same box under two different rules, and one of the differences changes how the whole panel reads. A Nutrition Facts panel on a food prints its mandatory nutrients whether or not there is any of them, so a zero is stated. 21 CFR 101.36 does the reverse for a supplement: any of those mandatory nutrients that is absent, or present in an amount that can be declared as zero, shall not be declared at all. The rows are removed rather than zeroed.

So a short Supplement Facts panel is a fact about the format before it is a fact about the product. Three lines can mean a single-ingredient powder with nothing else in it, or a formula containing nothing the rule counts. The second tell is the heading below the box. On a supplement the ingredient list is titled "Ingredients" ordinarily, and "Other ingredients" when the panel above has already named the sources; 21 CFR 101.4 makes that switch, and it is the reason the phrase exists at all.

Why is serving size the first thing to check?

Because every other figure in the panel is expressed per serving, and the serving is the brand's own recommendation handed back to it as a rule. The reference amount for a dietary supplement at 21 CFR 101.12 is the maximum amount recommended on the label for consumption per eating occasion, or, where the label recommends nothing, one unit. A container advertising 1,000 mg of something may deliver it across three capsules. Take one and you have taken a third.

Read that regulation twice, because it is circular by design and the circle is the whole mechanism. The serving size is not an external standard a product is measured against. It is the manufacturer's own instruction, written into the panel as though it were a finding. Nothing is being hidden — it is printed in the rule — but the number that governs every other number on the label is set by the party selling it.

The corollary is a pricing one. Divide the container price by the servings you will actually take, never by capsule or scoop count. A hundred-and-twenty-capsule bottle at four capsules a serving is a thirty-day bottle and belongs beside other thirty-day bottles. We run that division on our own three products, and one of the three answers costs us money.

What is "Amount Per Serving" actually telling you?

The quantity by weight of each dietary ingredient in one serving, as the manufacturer declares it — a statement about a formula, not a measurement of the container in your hands. Two decisions are stacked inside that one figure: how much of the ingredient goes in, and how much counts as one serving. Move the second and the first moves with it, and not a word of the panel becomes untrue.

This is the line where a label reaches the end of what it can do. A declared amount becomes a found amount only when a laboratory measures a defined quantity of the material and writes down what it found, which is a document rather than a panel. That is the last check in the procedure below, and it is a page of its own.

What does % Daily Value mean, and what does it not?

It is the amount in one serving expressed against a published reference intake for an average adult. It is a comparison scale, not a personal target and not a recommendation, and it is calculated from the declared amount rather than from a measured one — so a % Daily Value inherits every assumption in the figure above it. Where it earns its place is in catching quantities that are much larger than they look: an amount that reads as unremarkable in milligrams can read very differently as a share of a daily reference.

One thing it is not, and the confusion is common enough to be worth a line. A Daily Value is not an upper limit. The two are separate numbers set for separate purposes, and only the first appears on a panel. Night Work declares 275 mg of elemental magnesium at 65% of the Daily Value; the tolerable upper intake level for supplemental magnesium is a different figure entirely, it is not printed on any label, and it is the number worth knowing if anything else in the cabinet also contains magnesium.

Why do some ingredients show no % Daily Value at all?

Because no Daily Value has been established for them. It is the most common blank on a supplement label and it is required rather than accidental: 21 CFR 101.36 tells a manufacturer to put a symbol in the % Daily Value column for those ingredients and to place the same symbol at the foot of the box, followed by the words "Daily Value not established". Creatine, collagen peptides, botanicals, amino acids and most extracts are all in that position. Where nothing in a panel needs a figure in that column at all, the rule lets the column be dropped from the label entirely.

The honest half is what a blank does not mean. It is not a verdict on the dose. It does not say the amount is small, or generous, or pointless. It says that no reference intake exists to compare it against — so the comparison a reader is reaching for is not available on that label, at any price, from any brand, and no amount of squinting will produce it. Base Work's panel is the plain case: one dietary ingredient, 5 g of creatine monohydrate, and no Daily Value in existence for creatine to be measured against.

What is worth watching is what a brand puts in the space instead. A percentage against something other than a Daily Value, a footnote worded to resemble the required one, a symbol keyed to a marketing sentence — all of those occupy a column the rule intended to stand empty. The empty column is the honest version.

What is a proprietary blend, and why does it matter?

It is a group of dietary ingredients disclosed as one combined weight, with the individual amounts withheld. 21 CFR 101.36 permits it and sets the terms: the ingredients inside are listed in descending order of predominance by weight, and the one quantity printed is the total of the whole group. That is legal, it is common, and it makes the panel uncomputable — if the ingredient being bought sits inside a blend, its amount could be nearly the whole total or a trace at the bottom, and nothing on the label separates those two cases.

None of the three TARE panels carries one. Under Load and Base Work each declare a single dietary ingredient and Night Work declares a single magnesium compound, so there is nothing here for a blend to conceal — which is a fact about a three-product range, not a virtue we can charge for. The mechanism, the legality, the extract-versus-blend distinction and what the order does and does not let you infer are all on the blend page.

Compound weight against active weight — the division that catches most people

Minerals arrive attached to something. A capsule of magnesium glycinate is mostly glycine by weight; the magnesium is a fraction of it. So a panel can print a large compound figure and a much smaller elemental one, both truthfully, and the elemental figure is the one that counts.

Read the "as" language carefully, because it is where the two numbers separate. Magnesium (as magnesium glycinate) 275 mg is an elemental claim. Magnesium glycinate 2,500 mg is a compound claim. Same capsule, different statements, roughly a nine-fold difference between the numbers, and the front of a container tends to carry the larger one.

It is not a magnesium problem. Zinc, iron, calcium and potassium all arrive attached to something, and the same two numbers exist for each of them. The arithmetic, generalised, with our own 2,500 mg and 275 mg worked through, is the page this one hands you to; the form-by-form comparison is separate again.

What does "Other Ingredients" cover?

Everything in the container that is not a dietary ingredient declared in the panel above it. 21 CFR 101.4 puts that list immediately below the box and requires it to name the excipients, fillers, artificial colourings, artificial sweeteners, flavourings and binders — the capsule shell, the flow agents, the pressing aids, everything that made the product possible without being the product. It is a full ingredient list rather than a footnote, and on a great many labels it is longer than the panel it sits under.

The order deserves one careful sentence, because it is the part people over-read. The list runs in descending order of predominance by weight — but 21 CFR 101.4 lifts that requirement for ingredients present at 2 percent or less by weight, provided they are grouped at the end behind a qualifying line such as "Contains 2 percent or less of". Above that threshold, order is information. Below it, order is a printing convenience, and no arithmetic survives the crossing. The threshold itself can be set at 2, 1.5, 1 or 0.5 percent, and the label tells you which.

One more thing the list does not carry: quantities. Nothing in that line has a weight beside it. So it will tell you what is in the container and in roughly what rank, and it will never tell you how much of the capsule is shell and filler rather than the ingredient being paid for.

And now ours, which is that we have not published one. TARE has not published the "Other ingredients" line for any of the three products. Under Load's label sub-line reads ONE INGREDIENT and Base Work's panel carries a single dietary ingredient — but a one-ingredient panel is a statement about the panel and not about the line beneath it, and we are not going to tell you that line is empty on the strength of an inference. Night Work is a capsule, so it has a shell, and we have not published what the shell is made of either. Both are questions we have put to the manufacturer and not yet answered. They are recorded here as owed rather than filled in, which is the same rule this page has just asked you to hold every other label to.

What are magnesium stearate, silicon dioxide and microcrystalline cellulose doing in there?

Making the machinery work. Magnesium stearate is a lubricant that stops powder adhering to tooling; silicon dioxide is an anti-caking agent that keeps a powder flowing instead of clumping; microcrystalline cellulose is a bulking agent that gives a small quantity of active enough volume to fill a capsule or press a tablet. None of the three is a dietary ingredient, which is exactly why all three appear under "Other ingredients" rather than in the panel, and none of them is unusual.

The question worth asking is not whether they are present but how much of the container they are — and, as above, the label is not obliged to say. Where the declared actives in a capsule come to a few hundred milligrams and the capsule holds more, the difference is made up by something on that line, and the split is not printed anywhere. That gap between an ingredient list and a formula is the reason the last check in the procedure below is about a document rather than a label.

This page makes no health claim about any excipient in either direction. Whether a particular one suits a particular person is a question for a clinician, and it is not one a panel can settle.

Where do I find the lot number and the expiry date?

The lot code goes on when the container is filled, not when the label is printed, so it is stamped, inked or laser-etched rather than typeset — usually on the base, the shoulder, or beside the seal — and it looks different from everything else on the container for that reason. 21 CFR 111.415 requires a manufacturer to assign one to every lot of packaged and labelled supplement, and 21 CFR 111.3 defines it as the distinctive group of letters, numbers or symbols from which the complete manufacturing, packaging, labelling and holding history can be reconstructed. It is the only string on the container that points at your specific quantity of powder.

The expiry date is a different matter: nothing requires one. The word "expiration" does not appear once in 21 CFR part 111 — the manufacturing rule for dietary supplements — across all 136 of its sections. Where the rule touches the subject at all it does so conditionally, requiring reserve samples to be held for a year past the shelf life date "if shelf life dating is used". A supplement with no date on it is not breaking a rule. A date printed on one is the manufacturer's own statement rather than a required disclosure, and it is worth reading as such.

TARE has not published its own shelf-life convention. That is the second thing this page has to report as missing, and it is owed by us rather than by the reader.

The lot code earns its keep at the moment somebody offers you a certificate. A document naming a lot is a document about a defined quantity of material; whether that lot is the one in your container is a separate question, and across the category the answer is usually no. Of the three certificates TARE holds, one names the lot inside a TARE tub.

What does a certificate of analysis add, and what does it not?

It reports what a laboratory found in a defined quantity of material, which is more than any label can offer. What it does not do is connect itself to the container in your hands, and it does not necessarily assay the ingredient you are paying for. Two questions turn one into information: does it report measured results or only specification limits, and whose sample was it — a finished container off a real fill run, or a sack of raw material before it became anything.

Specification against result is the distinction that does most of the work. A specification is what a formula is supposed to contain. A result is what a test found. Both belong on a document, they are not the same thing, and a page that prints one while implying the other is counting on nobody looking. The same trap has a numeric version: a row can carry three numbers beside a metal's name and contain no measurement at all, because a detection threshold and an acceptance limit are properties of the method rather than findings about the sample.

Three pages carry the rest of this, and it is deliberately not repeated here: how to read a certificate line by line, the four questions that separate a real result from a decorative one, and why a facility mark is a statement about a building rather than about a product. Every row of all three of our own documents is transcribed at Testing & Certification.

The sixty-second procedure

Six checks, in order, on any container in any cabinet. They are all executable with the thing already in your hand, and the last one is the only one that needs anybody else.

1. Serving size, then servings per container. Every other number in the panel depends on the first, and the second is what price should be divided by — the servings you will actually take, not the capsule or scoop count.
2. Find the elemental or active figure under "Amount Per Serving". If the panel gives only a compound weight, or only an extract ratio, that is itself the finding. Where both numbers are printed, divide: active over compound, a fraction fixed by chemistry that does not care what the front of the container says.
3. Read the % Daily Value column, including the blanks. A symbol and "Daily Value not established" means no reference intake exists for that ingredient. It is not a comment on the dose. Anything else sitting in that column is worth a second look.
4. Look for a proprietary blend. If the ingredient in question is inside one, stop. Nothing above can be calculated, and the label has answered by declining to.
5. Read "Other ingredients." Not to be scandalised by flow agents, which are ordinary, but for two things: whether the list is longer than the panel above it, and whether a "2 percent or less" line at the end is quietly switching the order off.
6. Turn the container over, find the lot code, then ask for the document that names it. Then ask what kind of document it is: measured results or specification limits, and a finished container or a sack of raw material. A brand that cannot answer either question quickly has answered both.

Now run it on ours

Same six steps, same order, and this is where a label-literacy article usually goes quiet.

Two of those seven rows are the ones worth reading twice, and neither of them flatters us.

Under Load. Serving size 10 g, two 5 g scoops, thirty-five servings in a 350 g tub. One ingredient: 10 g of collagen peptides, delivering 9 g of protein. Nothing to divide, because there is nothing else in the panel. Step six is where it gets interesting, and it is the only one of the three that answers well: the certificate names lot 121125450, a 350 g lot of the powder our own tub was filled from, and reports protein measured at 9.8 g against a 9 g specification by ISO 14891:2002, with lead at 0.07 mcg against a 0.5 mcg Proposition 65 limit and mercury, arsenic and cadmium below the detectable limit. Right lot, real numbers — and it was run by ViaCore, the laboratory belonging to the company that manufactures the powder, rather than by an outside one. That is the weaker kind of check and we would rather you heard it from us.

Then step one, on the same product, against ourselves. The panel declares thirty-five servings of 10 g, and it is the panel that governs. This site's directions are three scoops, thirty to sixty minutes before training — a directions statement, never a serving declaration — and 15 g is one and a half of the declared serving. On that dose a 350 g tub is 23 whole doses, not 35, with an orphan scoop left that cannot make a twenty-fourth. Both numbers are true, they measure different things, and the smaller one is the one we run the arithmetic on: the full division, for all three products, is here.

Base Work. Serving size 5 g, sixty servings in a 300 g tub. One ingredient: 5 g of creatine monohydrate. No flavour system, no carrier, nothing whose quantity is unprinted, and no Daily Value in existence for creatine, so the % column has nothing to put beside it. Step six returns the strongest number and the strangest document on this site: an outside laboratory reports creatine monohydrate at 99.87% against a greater-than-99.5% specification, by HPLC. The sample photographed on that certificate is a sealed poly bag of raw material from Accobio USA, lot CM20251225A; the customer of record is the ingredient supplier rather than TARE; and the Serving Size field on it reads N/A, because a sack of powder does not have a serving. A real result about a real quantity of creatine. The sack is not the tub, and every row of it is transcribed.

Night Work. Serving size three capsules, thirty servings, ninety capsules. The panel declares 275 mg of elemental magnesium, 65% of the Daily Value, from 2,500 mg of magnesium glycinate — the compound figure and the elemental figure printed side by side, which is this page's own lesson on our own product. One magnesium compound on the panel.

And then the part that costs us. Those panel figures rest on the manufacturer's confirmation in writing, not on any certificate. The document held for Night Work covers a raw-material powder lot tested for another company. It carries a magnesium figure, 102.54 mg against a 91.6 mg specification, in the laboratory's own 926 mg serving rather than in three capsules; a heavy-metal page with a figure or a below-quantitation bound in every row, each a pass; seven microbiological rows, each a pass; and no identity test, so nothing on it says the powder is glycinate rather than oxide. So the one measured magnesium figure on this site is the powder's, in the laboratory's serving, and the label's 275 mg stays a label figure until a document carries it at three capsules. Because it is a capsule there is also a shell, and we have not published what that shell is made of. The certificate is transcribed row by row, including the row that was not run.

What a label can never tell you

Three things, and no amount of reading fixes them.

A panel is a claim, not a measurement. It states what the manufacturer says is in a serving. The document behind it is the only thing that turns a printed figure into a found one, which is why the last step of the procedure is about a document rather than a label.

A certificate names the lot it was run on, and that lot is not the buyer's. Naming a lot is exactly what separates a real certificate from a brochure — and a brand that never takes possession of inventory cannot connect the document to the jar that shipped. We would rather state the limit of our own paperwork than let anyone assume something larger.

No dietary supplement carries FDA approval, ours included, and registration would not be approval in any case. Structure/function claims carry an asterisk and a disclaimer; that is the system, and a label that implies more than that is telling you something about the brand.

Run the six checks on whatever is in the cabinet tonight. Then ask the last container bought for a document with a result and a specification on it, and see what comes back. That is the whole exercise, and it costs a minute.

Where each of these is answered in full

This page is the index. Each line goes to the page that owns the question, because a hub that restates its own cluster badly is worth less than one that admits where the real answer lives.

• Proprietary blends — the mechanism, the legality, and what the order of ingredients does and does not let you infer.
• Elemental against compound weight — the same two numbers in zinc, iron, calcium and potassium, with the arithmetic done longhand.
• What "tested" means — three different things wear the word, and the four questions that tell them apart.
• Certificates of analysis — specification against result, in one column, on our own documents.
• Facility marks — what an inspection of a building says about a product, which is less than the badge implies.
• Doses per container — net weight divided by the dose actually recommended, for all three of ours.
• Testing and certification — all three of our documents transcribed row by row, including the rows that read NOT RUN.

Two questions on this page we cannot yet answer about ourselves: the "Other ingredients" line for any of the three products, and a shelf-life convention. Both have been put to the manufacturer. When the answers arrive they will appear here, and if they are unflattering they will appear here anyway.