Dietary Supplement FAQs

Many consumers are concerned about the contents of vitamins, minerals, herbs, botanicals, protein bars or other supplements.

The fact that these products do not receive the same regulation as prescription or over-the-counter drugs can raise questions in the minds of many people. Whether answering questions about how these products are regulated, the scope and benefits of certification or how to read a supplement label, NSF International can provide useful information to help make an educated decision when shopping for dietary supplements, sports supplements or other nutritional products.

What does it mean when a supplement is NSF-certified?

There are multiple levels of certification for dietary supplements. At the first level, NSF provides GMP registration for companies. This means NSF audits a company’s production sites to confirm they are following Good Manufacturing Practices (GMPs) set forth for their industry. This is not a product certification, but ensures that companies follow best-practice procedures for production and process control systems, personnel, the physical plant and grounds, equipment and utensils, holding and distribution, etc. At the Contents Certified level, under the NSF/ANSI 173: Dietary Supplements standard, manufacturers must meet the GMP requirements above, and products must be evaluated to confirm that they contain the ingredients and quantities shown on the label and ensure they do not contain potentially harmful levels of impurities like heavy metals or pesticides. Certification must be renewed annually to ensure each product continues to comply with all requirements to maintain product certification. Visit NSF’s online listings to search for NSF certified supplements. A third level of certification, Certified for Sport®, applies to sports supplements.

What does it mean when a supplement is Certified for Sport®?

Products marketed for use by athletes can be evaluated under NSF’s Certified for Sport® program. This certification requires meeting all requirements for Good Manufacturing Practice (GMP) registration and NSF/ANSI 173: Dietary Supplements certification for content and labeling, plus NSF certifies products for a range of banned substances identified by the World Anti-Doping Agency (WADA) and leading sports organizations, such as Major League Baseball (MLB). We test for more than 270 stimulants, narcotics, steroids, diuretics, beta-2-agonists, masking agents and other substances. Ongoing monitoring helps ensure products continue to comply with all requirements to maintain product certification. Visit the NSF Certified for Sport® website to learn more about and search for NSF Certified for Sport® supplements.

Who ensures the safety of dietary supplements?

Supplement manufacturers are responsible by law to ensure their products are safe before being marketed. In addition, manufacturers are responsible for determining the accuracy and truth of label claims. The U.S. Food and Drug Administration (FDA) can take action against any unsafe dietary supplement product that reaches the market as well as any false or misleading claims.

How does regulation of supplements differ from that of prescription or over-the-counter drugs?

Before marketing, drugs must undergo clinical studies to determine their effectiveness, safety, possible interactions with other substances and appropriate dosages. FDA then reviews this data and determines whether to authorize use of the drugs. Dietary supplements fall under the general category of food products. Unless they contain a new ingredient, dietary supplements are not tested or authorized for use prior to being marketed, but the FDA has oversight over these products and can limit the type of ingredients used in product formulations and take action when false or misleading label claims are made.

Are products manufactured in an NSF GMP-registered facility considered to be certified?

GMP registration does not apply to individual products. Rather, it is a facility registration designed to help verify that a manufacturer is following the Good Manufacturing Practices (GMPs) established for its industry. Products from a GMP-registered facility may not bear the NSF certification mark. Although no product testing is conducted as part of a GMP audit, there are product certifications available that do include product testing to help confirm whether a product contains the ingredients/quantities shown on the label (NSF/ANSI 173) as well as to determine if it is free of banned substances (Certified for Sport®). Both of these product certifications allow NSF certification marks to appear on the label.

What types of products are classified as dietary supplements?

Dietary supplements are defined as products taken by mouth that contain a “dietary ingredient” intended to supplement a person’s diet. Products meeting this definition include vitamins, minerals, herbs, botanicals, amino acids and concentrates, metabolites, and constituents and extracts of these substances.

What can consumers do to protect themselves when purchasing dietary supplements?

Consumers should look for the NSF mark on the product label. This mark indicates that the product has been tested to ensure that it contains the ingredients and quantities listed on the label and that no unlisted ingredients or potentially harmful levels of impurities are present in the product. In addition, a claim that a product is “all natural” is not a guarantee that the product is safer. Avoid products with label claims that the supplement is a new treatment or cure for a specific disease or condition. No companies are authorized under current federal regulations to make such claims for dietary supplements. Consumers can report supplements making such claims to the U.S. Food and Drug Administration.

Should people check with a health care provider before taking supplements?

Dietary supplements may not be totally risk-free under all circumstances. Some supplements can interact with prescription or over-the-counter medications or could contain active ingredients that have strong biological effects and can cause adverse reactions in some people. Some supplements can also have unwanted effects during surgery. Therefore, it’s important for consumers to fully inform their doctor about the vitamins, minerals, herbs or any other supplements they are taking, especially before surgery or when being placed on a prescription medication.

Who regulates dietary supplement advertising?

The Federal Trade Commission (FTC) regulates advertising for dietary supplements and most other products sold to consumers. Advertising and promotional material received via U.S. mail are subject to regulation by the U.S. Postal Inspection Service.