How do you read a supplement label?

Does FDA approve dietary supplements?

No. Under the Dietary Supplement Health and Education Act of 1994 (DSHEA), FDA does not have the authority to approve dietary supplements for safety and effectiveness, or to approve their labeling, before they are sold. Supplement companies are responsible for making sure their products are safe and their labels are truthful. FDA

DSHEA is the 1994 federal law that defined “dietary supplement” and set out FDA’s authority over supplements, which is mostly after they reach the market. FDA

NIH’s Office of Dietary Supplements puts it plainly: medicines must be approved by FDA before they can be sold; supplements do not require this approval. NIH ODS

What does “not evaluated by the Food and Drug Administration” mean?

It means FDA has not reviewed the claim next to it. Federal rules require this disclaimer whenever a supplement makes a structure or function claim, such as “supports sleep”: “This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.” 21 CFR 101.93

A structure/function claim is a statement about how a nutrient or ingredient affects the body’s normal structure or function. The company must notify FDA no later than 30 days after first marketing a product that carries one. 21 CFR 101.93

What is on a Supplement Facts panel?

The Supplement Facts panel is the box that lists the serving size, each dietary ingredient and its amount per serving. Federal rules require the title “Supplement Facts” to be in a larger type than anything else in the panel, so it is easy to find. 21 CFR 101.36

• Serving size and servings per container: the amounts listed are per serving, not per container. 21 CFR 101.36
• Each dietary ingredient and its amount, unless it is inside a proprietary blend. 21 CFR 101.36
• Other ingredients, such as fillers, binders and capsule materials, listed below the panel. 21 CFR 101.36

What is a proprietary blend on a supplement label?

A proprietary blend is a named mix of ingredients for which the label gives only the total weight of the blend, not the amount of each ingredient in it. That means you cannot tell from the label how much of any one ingredient you are getting. 21 CFR 101.36

What do USP, NSF and Informed Sport seals mean?

They mean an independent organization tested the product or its batches against a standard. They do not mean the product is safe or effective: NIH’s Office of Dietary Supplements says these seals do not show that. They mainly confirm what is in the bottle and screen for contaminants or banned substances. NIH ODS

NSF describes its certification and the Certified for Sport screen on its own site. NSF

Informed Sport, run by LGC, describes its batch testing on its own site. Informed Sport (LGC)

What is a new dietary ingredient?

A new dietary ingredient is one that was not marketed in the US as a supplement before October 15, 1994. A company must notify FDA before selling a supplement that contains one. NMN is an example: FDA said in September 2025 it can be sold as a supplement, and sellers still need a notification on file. FDA

What should you check before buying a supplement?

Check the Supplement Facts panel for exact amounts, avoid proprietary blends if you want to know what you are taking, look for an independent testing seal, and ask a pharmacist or clinician about interactions with your medications. Labels can be wrong: a 2023 study found 22 of 25 melatonin gummies were inaccurately labeled. NCCIH

• Be wary of disease claims. A supplement cannot lawfully claim to treat or prevent a disease; that claim belongs to drugs. 21 CFR 101.93
• Some supplements interact with prescription drugs. Berberine, for example, can add to diabetes medications and interact with others. NCCIH
• If you compete in tested sport, choose NSF Certified for Sport or Informed Sport products. NSF

Reading a supplement label: questions, answered

Sources

1. FDA: FDA 101, dietary supplements
2. FDA: Dietary supplements
3. NIH ODS: Dietary supplements, what you need to know
4. 21 CFR 101.93: Structure/function statements and the required disclaimer (Cornell LII)
5. 21 CFR 101.36: Supplement Facts labeling and proprietary blends (Cornell LII)
6. FDA: New dietary ingredient (NDI) notification process
7. Venable LLP: FDA declares nicotinamide mononucleotide is a dietary supplement (Oct 2025)
8. USP: USP Verified Mark
9. NSF: Supplement and vitamin certification
10. Informed Sport (LGC): batch testing of sports supplements
11. NCCIH: Melatonin, what you need to know
12. NCCIH: Berberine and weight loss, what you need to know

Last reviewed September 23, 2026. Every source above was checked on or before that date. Educational information only, not medical advice; it does not replace a conversation with a licensed clinician. DiscoverMedica does not employ clinicians.