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Providing perspectives on recent research into vitamins and nutritionals


Ensuring the Quality of Dietary Supplements

By Julia Bird

Most dietary supplement manufacturers want to make a product that is safe for the consumer and promotes health. I know from my work at DSM that various quality management systems are used in our factories to ensure that production processes are defined and controlled, potentials risks from raw ingredients and the manufacturing process are identified and minimized, and that the final product meets specifications and is tested for contaminants that may pose a risk to the end user. While this is often presented as a way to prevent costly recalls, I would be ashamed as an employee if DSM products caused adverse events in consumers. I want to work for a company that improves people's lives.

As TalkingNutrition discussed in November last year, not all producers of dietary supplements make products that are safe. Some dietary supplements are found to be adulterated, or may otherwise pose a health risk to consumers. The quality of dietary supplements sold in the US is the responsibility of the manufacturer, and not an external party. Incompetent or deliberately negligent supplement manufacturers may therefore put products on the market that can damage health.

What can the consumer do to make sure that their supplement contains what it says, nothing more and nothing less? In our previous article, we mentioned one program used to certify dietary supplements, the USP program. However there are two more that also evaluate supplements to ensure that they do not pose a safety risk, as described by Akabas and co-workers. The three programs are run by the US Pharmacopeial Convention (USP), NSF International, and These three quality certification programs all assess the quality and identity of dietary supplements via independent testing of off-the-shelf products.

All three programs have specific criteria that products must adhere to before they are verified, certified or receive the program’s seal of approval. The criteria relate to the quality, safety, performance and claims of the product. The exact criteria used vary a little according to the program, but there are clear similarities between all three. Products are sampled at random from the marketplace and their quality, safety, performance and claims are tested. Under the quality criterion, the supplement must contain the amount of the substance as reported on the label, and contaminants must be under specified levels.  The safety criterion refers specifically to contaminants with a known safety risk, and more stringent criteria or labelling requirements are in place for certified products. The products have a performance criterion, which checks that the product will disintegrate or dissolve in a liquid within a specified time and that the product will therefore be available to the body. There is also a criterion based on claims: the ingredient list must be accurate, and any health claims on the product should be realistic and in line with regulatory requirements. Companies that produce dietary supplements are also audited to make sure that their manufacturing facilities adhere to industry standards.

Certification by one of these three independent organizations shows that the manufacturers have ensured that their product is safe, able to be taken up by the body, and that the product labelling is factual. The article is open access and provides more detailed information on the regulatory environment for dietary supplements and how the certification programs work.

Main citation:

Akabas, Sharon R. et al. Quality Certification Programs for Dietary Supplements. Journal of the Academy of Nutrition and Dietetics. Published Online: January 12, 2016.