Supplements in the US do not need FDA approval before they go on sale, so the label is often your best tool for judging a product. Most labels follow the same layout, and a few minutes of checking can save you money and help you avoid poor products. Here are nine warning signs to look for.
If you are new to reading labels, start with our guide on how to read a supplement label.
1. A proprietary blend
A "proprietary blend" lists several ingredients under one total weight without saying how much of each is inside. That makes it impossible to know whether you are getting a useful amount of anything. Our explainer on proprietary blends shows how they can hide tiny doses.
2. Doses far below what was studied
A product might contain an ingredient with good research behind it, but at a fraction of the amount used in studies. For example, creatine is studied at 3 to 5 grams a day, so a product with 500 milligrams per serving is unlikely to do much. Compare the amount per serving to the reference amounts on our ingredient pages, such as creatine or magnesium.
3. A serving size that hides the real cost
Some products need 3, 4 or even 6 capsules or gummies per serving. The bottle looks cheap, but it runs out fast. Always check servings per container and work out the cost per serving. Our guide to supplement serving sizes explains what to watch for.
4. Disease claims
Supplements are not allowed to claim they treat, cure or prevent a disease. Words like "cures", "reverses diabetes" or "kills viruses" are a sign the company is ignoring the rules, and it is fair to wonder what else it is ignoring. Our article on how supplements are regulated explains what is allowed.
5. Promises that sound too good
"Lose 20 pounds in two weeks", "clinically proven to triple testosterone" or "works for everyone" are red flags. Real research rarely produces dramatic results, and when it does, the effect is usually smaller and slower than ads suggest.
6. "Clinically proven" with no study named
Some labels say "clinically studied" or "backed by science" without saying which study, how many people took part, or whether the study used the same product and dose. If the company cannot point to the research, assume it does not exist. Our guide on how to read health studies can help you judge the ones they do cite.
7. No third-party testing seal
Independent testing by groups like USP or NSF checks that a product contains what the label says and is not contaminated. A missing seal does not mean a product is bad, but a seal gives you real assurance. Be wary of vague claims like "lab tested" with no named lab. Learn what third-party tested means.
8. Megadoses of vitamins and minerals
More is not always better. Some vitamins and minerals, such as vitamin A, vitamin D, iron and zinc, can cause harm at high doses taken for a long time. Check the % Daily Value column. Our guide to percent Daily Value on supplement labels explains how to read it.
9. Product categories with a history of hidden drugs
Weight loss, sexual enhancement and bodybuilding products are the most likely to contain undeclared prescription drugs. The FDA keeps a list of tainted products sold as supplements. Be extra careful with these categories and buy from trusted sellers. See where to buy supplements safely.
What a good label looks like
- Every active ingredient is listed with its own amount.
- Amounts match what was used in research.
- The form of each ingredient is named, such as "magnesium glycinate" rather than just "magnesium".
- It carries a recognized third-party testing seal.
- Claims are modest and do not mention diseases.
- It lists a manufacturer or distributor you can contact.
Every product on SuppScout shows these details side by side, so you can compare products without reading the fine print yourself.