Roughly 80% of American adults take at least one dietary supplement. And yet most people couldn't explain what half the things on a supplement label actually mean. That's not their fault. These labels are designed to look informative while burying the details that actually matter.
Here's what you need to know to stop getting played by clever packaging.
Every supplement sold in the U.S. is required to carry a Supplement Facts panel. It looks similar to the Nutrition Facts label on food, but there are key differences. The FDA mandates this panel under the Dietary Supplement Health and Education Act (DSHEA) of 1994, and it follows a specific format.
Start at the top. The first thing listed is serving size.
This is where companies pull their first trick. A bottle might advertise "500mg of Ashwagandha!" on the front label, but the serving size is 2 capsules. Each capsule only contains 250mg. You'd need to take two to get the advertised amount. Some products push it further — a serving size of 3 or even 4 capsules for what seems like a standard dose.
Always check servings per container too. A "30-day supply" that requires 2 capsules per serving with only 30 capsules in the bottle? That's 15 days. Companies do this constantly.
The % Daily Value (DV) column tells you how much of a nutrient one serving provides relative to the recommended daily intake, based on a 2,000-calorie diet. The FDA updated these reference values in 2020, so older products may show different numbers.
A few things to keep in mind:
For water-soluble vitamins (B vitamins, vitamin C), high percentages aren't usually dangerous. Your body excretes what it doesn't need. But for fat-soluble vitamins — A, D, E, and K — excess amounts get stored in body fat and can accumulate to harmful levels over time.
If you see a vitamin A supplement with 900% DV, that's a legitimate concern. Chronic vitamin A toxicity can cause liver damage, headaches, and bone loss. The tolerable upper intake for adults is 3,000 mcg RAE per day, per the National Institutes of Health.
Some ingredients show a double dagger (‡) instead of a percentage. That means the FDA hasn't established a Daily Value for that nutrient. This is common with things like CoQ10, lutein, and most herbal extracts. It doesn't mean the ingredient is unregulated — it just means there's no official recommended daily amount.
This is the single most important thing to watch for on any supplement label.
A proprietary blend lists a group of ingredients under one combined total weight without telling you how much of each ingredient is in the mix. Legally, manufacturers only have to list the total weight of the blend and the individual ingredients in descending order by weight.
Here's what that looks like in practice. Say a label reads:
Cognitive Support Blend: 800mg
(Ginkgo biloba, Bacopa monnieri, Lion's Mane, Phosphatidylserine, L-Theanine)
You know the blend totals 800mg. You know ginkgo is the largest ingredient by weight. But the ginkgo could be 790mg with everything else at trace amounts. Or each could be roughly 160mg. You have no way to tell.
This matters because dosing determines whether an ingredient actually works. Bacopa monnieri needs roughly 300mg per day (standardized to 55% bacosides) to show cognitive benefits in clinical trials. If a proprietary blend only contains 50mg of bacopa, you're not getting a therapeutic dose. You're getting a label claim.
Why do companies use proprietary blends? Two reasons. First, they claim it protects their "unique formula" from competitors. Second — and honestly, this is the main reason — it lets them under-dose expensive ingredients while keeping them on the label. A pinch of an expensive extract still counts as an ingredient.
Rule of thumb: If a product uses proprietary blends, skip it. There are too many transparent alternatives available now to justify guessing at doses.
Below the Supplement Facts panel, you'll find a section called "Other Ingredients." These are the inactive ingredients — the stuff that makes up the capsule, holds the tablet together, prevents clumping, or adds flavor and color.
Not all of these are bad. Some are necessary. But some are worth avoiding.
The shorter the "Other Ingredients" list, the better. Premium brands often list just the capsule material and maybe one or two binders.
The FDA has no formal regulatory definition for the word "natural" when it comes to supplements. None. A company can slap "All Natural" on a product that contains synthetic vitamins, artificial flavors, and heavily processed extracts. There's no enforcement mechanism because there's no rule to enforce.
This is different from "organic," which does have a legal definition enforced by the USDA. If a supplement claims to be USDA Organic, the ingredients must meet organic farming standards and the product must be certified through an accredited certifying agent.
Other meaningless marketing terms on supplement labels:
Active ingredients are the ones listed in the Supplement Facts panel with specific amounts. These are the ingredients that are supposed to deliver the health benefit. Inactive ingredients (the "Other Ingredients") are everything else that makes up the physical product.
But there's a subtlety here that trips people up. The form of the active ingredient matters enormously.
Take magnesium. A label might say "Magnesium — 400mg." But magnesium comes in many forms: magnesium oxide, magnesium citrate, magnesium glycinate, magnesium L-threonate, and more. Magnesium oxide has a bioavailability of roughly 4%, meaning your body absorbs very little of it. Magnesium glycinate has significantly higher absorption rates. Same element, vastly different results.
The same applies to other nutrients:
| Nutrient | Cheaper Form | Better-Absorbed Form |
|---|---|---|
| Vitamin B12 | Cyanocobalamin | Methylcobalamin |
| Folate | Folic acid | Methylfolate (5-MTHF) |
| Iron | Ferrous sulfate | Iron bisglycinate |
| CoQ10 | Ubiquinone | Ubiquinol |
| Curcumin | Standard curcumin extract | Curcumin with piperine or phytosome form |
If a label doesn't specify the form of the ingredient, that's a yellow flag. Quality brands always list the specific form because they want you to know you're getting the good stuff.
Here's a scenario that plays out thousands of times a day. Someone buys a multivitamin because the label says it contains 100% DV of 20+ vitamins and minerals. Sounds great. But the serving size is 3 tablets. They take one tablet in the morning — the way most people take pills — and they're only getting a third of what's listed.
Gummy vitamins are particularly bad about this. A serving is often 2-3 gummies. And because you need gelatin, sugar, and flavoring to make a gummy, there's less room for actual active ingredients. Many gummy vitamins contain significantly lower doses compared to their capsule equivalents.
Powder supplements play the serving size game differently. The scoop included in the container might not match the serving size listed on the label. The label says a serving is 10g, but the scoop holds 7g. Unless you're weighing your powder (which almost nobody does), you're consistently under-dosing.
Under FDA regulations, supplement labels can make "structure/function claims" without pre-approval. These are statements like "supports immune health" or "promotes joint comfort." They cannot claim to diagnose, treat, cure, or prevent any disease — that would make it an unapproved drug.
But manufacturers push these boundaries constantly. A product can't say "cures arthritis," but it can say "supports healthy joint function" right next to a picture of someone jogging pain-free. The implied message is the same. Technically legal, practically misleading.
Every structure/function claim must be accompanied by this disclaimer (usually in tiny print): "These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease."
If you don't see that disclaimer, the product is either making illegal claims or cutting corners on compliance. Neither is a good sign.
Next time you're evaluating a supplement, run through these checks:
It takes about 60 seconds once you know what to look for. Or you can scan the product with an app like Suppi and get an instant breakdown of every ingredient, dose, and potential red flag.
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