How to read a supplement label (US)

A US supplement label tells you what the manufacturer says is in one serving and what it is allowed to claim, not whether the product works or whether an independent party has checked it. Once you know where to look, the Supplement Facts panel answers three practical questions: how much of the active ingredient you get, whether that matches the dose studied in trials, and what else is in the bottle.

What a supplement label is

Under the Dietary Supplement Health and Education Act of 1994 (DSHEA), supplements are regulated as a category of food, not as drugs. The FDA does not approve supplements before they are sold, and its labeling guide states that label approval is not required to import or distribute one. Manufacturers are responsible for making sure their products are safe and their labels truthful and not misleading. The FDA acts after products reach the market, through warning letters, recalls and enforcement. Advertising claims fall under the Federal Trade Commission.

The front of the package must show a statement of identity that names the product as a dietary supplement and the net quantity of contents. The side or back panel must carry the Supplement Facts panel, the ingredient list, and the name and place of business of the manufacturer, packer or distributor. That contact information is also where you report a problem to the company.

Why it matters in midlife

Many women in perimenopause end up taking several products at once: vitamin D, a magnesium for sleep, a “menopause support” blend, maybe a collagen or omega-3. Ingredients overlap, and fortified foods add more. The Office of Dietary Supplements warns that more is not necessarily better, and that taking several supplements, or taking them alongside prescription medicines, raises the chance of side effects and interactions. Reading labels carefully is how you avoid doubling up and how you compare a product with the doses used in research.

Reading the Supplement Facts panel, step by step

1. Serving size. This is the maximum amount the label recommends per eating occasion, or one unit if no recommendation is given. Every amount below it is per serving. If a serving is three capsules and you take one, you are getting a third of the listed dose.

2. Amount per serving. For vitamins and minerals, the number is the nutrient itself, sometimes called the elemental amount. FDA guidance uses the example of declaring the weight of calcium rather than calcium carbonate. A source compound such as “as magnesium glycinate” may be named, but the milligrams refer to the magnesium. Vitamin D now appears in micrograms (mcg) and often IU as well; 1 mcg equals 40 IU.

3. Percent Daily Value (% DV). Required for any nutrient that has an established Daily Value, calculated from the amount per serving. Ingredients without a Daily Value, such as herbs, creatine or omega-3 fatty acids, carry a symbol pointing to the footnote “Daily Value not established.”

4. Botanicals. The label must name the part of the plant used, such as root or leaf. Dried extracts are listed by the weight of the extract. Liquid extracts are listed by volume or weight along with the condition of the starting material. Standardization to a marker compound, such as withanolides in ashwagandha, may also be stated. NCCIH cautions that a manufacturer’s use of “standardized,” “verified” or “certified” does not by itself guarantee quality or consistency.

5. Proprietary blends. A blend is listed with the total weight of all its ingredients on one line, followed by the ingredients in descending order of weight, without individual amounts. You can tell which ingredient is largest, not how much of any one you get.

6. Other ingredients. Fillers, binders, flavorings, colors and capsule materials appear in a separate list below the panel. Check here for allergens, sweeteners and gelatin if they matter to you.

Claims on the front of the bottle

Supplements may carry three kinds of claims, and none may say the product treats, cures or prevents a disease.

• Structure/function claims, such as “supports restful sleep” or “promotes bone health,” need no FDA approval. The company must have substantiation, notify the FDA within 30 days of marketing, and print this exact disclaimer: “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.”
• Health claims describe a link between an ingredient and lower risk of a disease and require FDA authorization based on significant scientific agreement.
• Nutrient content claims such as “high in vitamin C” must meet FDA definitions.

The disclaimer is the clearest signal that the claim has not been evaluated for effectiveness.

What the evidence shows about label accuracy

The label is only as good as the company’s manufacturing. Manufacturers must follow current good manufacturing practices meant to ensure identity, purity, strength and composition, and the FDA inspects facilities periodically. Independent testing still finds gaps. In a 2022 study, researchers bought 30 immune-support supplements from Amazon and analyzed them with liquid chromatography and mass spectrometry. Only 13 had accurate labels. Of the 17 that did not, 13 listed ingredients that were not detected and 9 contained substances not on the label. None carried a third-party certification seal. NCCIH puts it plainly: what is on the label may not be what is in the product.

Matching the label to the research dose

To compare a product with a trial, match three things: the same form (for example, root extract versus leaf, D3 versus D2, creatine monohydrate versus other forms), the same amount of the active compound per day, and the same standardization where it applies. A blend rarely lets you do this.

Safety and interactions

A label will not warn you about every interaction. The Office of Dietary Supplements gives examples: vitamin K can reduce the effect of the blood thinner warfarin, and St. John’s wort can speed the breakdown of many medicines, including some antidepressants and birth control pills. Some supplements increase bleeding risk or change your response to anesthesia before surgery. If you take hormone therapy, an SSRI or SNRI, thyroid medication or a blood thinner, show your supplement labels to a pharmacist, and keep a written list of everything you take.

How to choose a product

• Prefer single-ingredient products with the amount stated per serving.
• Check the serving size before comparing prices or doses.
• For minerals and vitamins, read the elemental amount and the units.
• For herbs, look for the plant part, extract amount and standardization.
• Be wary of proprietary blends when dose matters.
• Look for an independent certification mark, which addresses accuracy but not effectiveness.
• Watch for disease language, which supplements are not allowed to use.

Bottom line

The Supplement Facts panel is the most useful part of the bottle and the front is the least. Read the serving size, the elemental amount and the other-ingredients list, and treat claims as marketing. If you are weighing supplements against symptoms such as hot flashes or poor sleep, the symptom check can help you organize what is happening, and a menopause-literate clinician can tell you which products, if any, are worth trying. See how to find a menopause specialist.