VITAMINS & SUPPLEMENTS · GUIDE
Dietary Supplements vs Medicines: How Testing and Oversight Differ
How US oversight of dietary supplements differs from medicines: what is checked before sale, what is checked after, and what the difference does and does not tell you.
Content last updated . This page has not been medically reviewed.
Back to Compare SupplementsThe question
Are dietary supplements checked the way medicines are? In the United States, no: the two follow different legal rules, and the checks happen at different times. This page describes those differences using US Food and Drug Administration (FDA) and NIH pages. It is information only and does not tell you what to take. Other countries set their own rules; see Supplement regulation by country and How supplements are regulated.The two options side by side
Prescription or over-the-counter medicine (US)
Regulator statementA product that must go through FDA drug review before sale.
Dietary supplement (US)
Regulator statementA swallowed product labeled as a dietary supplement, such as a pill, capsule, gummy or powder. [2]
What is checked, and when
| Question | Medicines | Dietary supplements |
|---|---|---|
| Is the product reviewed before sale? | Yes. FDA reviewers study the company's trial data and proposed label. [1] | No approval step. FDA says unlike drugs, which "must be proven safe and effective for their intended use before marketing," supplements are mainly policed after they reach shelves. [2] |
| Who is responsible for safety and labeling? | The drug maker submits evidence; FDA reviews it. [1] | Manufacturers and distributors are responsible for the safety and labeling of their products before marketing. [3] |
| Does FDA test the product first? | The review team does not test drugs itself, but it reviews the maker's data. [1] | "FDA does not test dietary supplements before they are sold to consumers." [2] |
| Manufacturing rules | Not covered in the pages we read. | Makers must follow current good manufacturing practices that help ensure "identity, purity, quality, strength, and composition." [2] |
| What can the label claim? | FDA says "only a drug can legally make" a claim to diagnose, treat, cure or prevent a disease. [2] | A product sold as a supplement but represented for treating or preventing a specific disease "meets the definition of a drug." [2] |
| New ingredients | Not covered in the pages we read. | Makers must notify FDA at least 75 days before marketing a supplement with a new dietary ingredient, with their safety basis. [2] |
| Amount per serving | Not covered in the pages we read. | FDA says there are "no laws or regulations that limit the serving size" or the amount of an ingredient, apart from safety and labeling duties. [2] |
| After sale | Not covered in the pages we read. | FDA can act against adulterated or misbranded products after they reach the market, and firms must forward serious adverse event reports. [3][2] |
What the difference does and does not mean
- Claims. Statements such as "supports joint health" are called structure/function claims. FDA says these are "not approved by FDA and do not require FDA evaluation" before use. [2] See Structure-function claims vs health claims vs disease claims.
- Contents. NCCIH warns that "What's on the label may not be what's in the product," and that FDA has found prescription drugs in some products sold as supplements. [4] Independent labs and quality programs are described on Quality testing and certifications.
- Advertising is shared: FDA is generally responsible for safety, quality and labeling, and the Federal Trade Commission for advertising. [2]
- Head-to-head evidence. Proper evidence not found that supplements as a group are more or less safe than medicines as a group. We searched the FDA, NCCIH and PubMed pages listed below; the sources describe rules, not a ranking of safety.
No universal winner
Medicines have a pre-sale review and supplements do not, but each product still has to be judged on its own label, ingredients and your own health situation. Neither category is "safe" or "unsafe" by definition.Frequently asked questions
Does FDA approve dietary supplements?
No. FDA says it does not have the authority to approve dietary supplements before they are marketed. [2]
Does FDA test supplements before they are sold?
FDA says it does not test dietary supplements before they are sold to consumers. [2] It can examine samples collected during inspections or pulled from store shelves for routine monitoring. [2]
Are supplements regulated at all in the US?
Yes, under a different set of rules than medicines. [3] Makers must follow manufacturing practices, label requirements and adverse event reporting rules. [2]
Why does a supplement label say it has not been evaluated by FDA?
FDA says that statement is required by law when a label makes a structure/function claim, because those claims are not approved by FDA. [2]
Can a supplement claim to treat a disease?
FDA says a product represented for treating, preventing or curing a specific disease meets the definition of a drug. [2]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
How to read the evidence labels
Labels used on this page: regulator statement (what an agency says its rules are), observational testing (a lab study of products on shelves) and Proper evidence not found (we looked and the sources we read do not say).
Safety and who should ask a clinician
- Interactions. NCCIH says supplements "may interact with your medications or pose risks if you have certain medical problems." [4] Tell your pharmacist or clinician about everything you take; see Medication interactions.
- Pregnancy, breastfeeding and children. Many supplements "haven't been tested in pregnant women, nursing mothers, or children." [4] Ask a clinician first; see Pregnancy and breastfeeding.
- Kidney or liver conditions. The sources we read for this page do not give condition-by-condition limits; ask a clinician or pharmacist.
- Before surgery. Some supplements may raise bleeding risk or change the response to anesthesia, so tell the surgical team early. [4]
- Never stop or swap a prescribed medicine for a supplement without the prescriber.
- Swallowed too much, or a child got into a bottle? In the US call Poison Help at 1-800-222-1222, or 911 if the person is unwell. See Poison Help by country.
References
- FDA (US), Development & Approval Process (Drugs) Read 2026-10-23.
- FDA (US), Questions and Answers on Dietary Supplements Read 2026-10-23.
- FDA (US), Dietary Supplements Read 2026-10-23.
- NCCIH, NIH (US), Using Dietary Supplements Wisely Read 2026-10-23.