Get Involved
About Us
Our Members
Third-Party Evaluation Programs for the Quality of Dietary Supplements

by Marie K. Whybark, MS, RD

When consumers, healthcare practitioners, and researchers select dietary supplements, they have the challenge of trying to determine which products are most likely to meet their needs. For any given supplement, there is often a variety of brands, different doses and formulations, pills, extracts, and some that are sold as mixtures with other ingredients, and so forth. Choosing the right product requires skill in determining what is needed and which product is most likely to fit the need. This is often based on clinical need and personal preferences. Just as challenging as picking a form and dose is selecting a product that instills confidence in the quality of the product. In the past few years, the media has been filled with headlines regarding the safety of dietary supplements and the reports that products are not always what they claim to be. Entire Web pages are dedicated to providing information about recalls of dietary supplements and the challenges of finding a trustworthy product.

Fortunately for consumers and others, deciding which brands are reliable is getting easier everyday, thanks to independent certifiers of dietary supplements. In an effort to maintain the trust of consumers and demystify the process of selecting a supplement, various members of the dietary supplement industry have supported the efforts of independent organizations offering evaluations and certifications of dietary supplements. A little bit of knowledge about this handful of organizations providing evaluations of dietary supplements can greatly assist consumers in selecting a product, practitioners in recommending products, researchers in studying supplements, and even the industry itself in deciding how to demonstrate the quality of products in the marketplace.

Although the National Nutritional Foods Association’s TruLabel Program has been in operation since 1990, one of the first groups to grab the consumer’s attention in this arena was (CL), founded in 1999. Shortly thereafter, NSF International (NSF) entered the ring, rushing to provide a valuable service to those wishing to purchase dietary supplements. In addition, the United States Pharmacopeia (USP) decided to apply its standards-setting expertise to a program to verify supplements for the public’s benefit.

Standards for Dietary Supplements

One of the first challenges faced by these eager organizations was determining what criteria to use to evaluate a specific dietary supplement. “Standard” is a term that can mean many things and has been used to refer to authenticated reference standards, standardized extracts, standardized test methods, and product standards. To meet the challenge of developing appropriate standardized test methods, several organizations, including the USP, AOAC International, and NSF, have worked to develop validated methods for evaluating supplements, including botanicals and other products.

To address the need for product standards, NSF worked with industry experts to develop an American National Standard for Dietary Supplements, NSF/ANSI 173-03 Dietary Supplements.The NSF/ANSI standard sets limits for contaminants, including substances such as pesticides, microbial count, and heavy metals; it establishes criteria for verifying the quantity of active ingredients; and it sets criteria for compliance with Good Manufacturing Practices (GMP) and label requirements. Standards are documented agreements containing technical specifications or other precise criteria to be used consistently as rules, guidelines, or definitions of characteristics to ensure that materials, products, processes, and services are fit for their purpose. Once standards are established, evaluations can be made to determine if a product complies with the standard. This is referred to as “conformity assessment.”

American National Standards are developed in accordance with the requirements for standards development set forth by the American National Standards Institute (ANSI), a private, non-profit organization that administers and coordinates the U.S. voluntary standardization and conformity assessment system. ANSI standards are developed based on the principles of due-process, participation, and consensus. The NSF/ANSI standard for dietary supplements was developed by the NSF Joint Committee for Dietary Supplements which includes a balanced membership of individuals representing the regulatory community, the dietary supplements industry, and consumer representatives. Although NSF developed the ANSI standard for dietary supplements, this standard can be used by any individual or organization wishing to evaluate dietary supplements. It is a comprehensive standard that includes vitamins, minerals, botanicals, and other types of dietary supplements. For more information about NSF/ANSI 173-03 Dietary Supplements or to purchase a copy, access the NSF Web site at /index.asp?program=DietarySups.

Additionally, the USP verification program tests supplements and manufacturing practices against its own standards for nutritional and dietary supplement products. These standards are compiled in USP’s National Formulary 22.1 Section 7 of the Dietary Supplement Health and Education Act of 1994 recognizes USP National Formulary 22 as the nation’s official compendia for supplement standards. USP also establishes reference standards materials that are used to test dietary supplements and ingredients for identity, strength, quality, and purity. As an indicator of some of the cross-pollination that occurs in the field of standard setting, USP’s monographs are referenced in the NSF/ANSI 173-03 Dietary Supplements standard.

Table 1. List of Acronyms

ANSIAmerican National Standards Institute
DSVPDietary Supplement Verification Program
GMPGood Manufacturing Practices
NNFANational Nutritional Foods Association
NSFNSF International
USPUnited States Pharmacopeia


Conformity Assessment

Having a standard opened the door for consistent conformity assessment of dietary supplements. Conformity assessment is an activity concerned with determining directly or indirectly that relevant requirements are fulfilled by sampling, testing, and inspecting. Conformity assessment establishes confidence in the products and services consumers purchase. This involves confidence in a company’s promise of performance. Sometimes, there is a marketplace need or regulatory requirement for third-party certification or performance, usually in the areas of health, safety, and the environment.

The three types of conformity assessment are self-declaration, one-time verification, and third-party certification.

1. Self-declaration allows a manufacturer to declare that the product complies with a standard. This is typically conducted in a first-party scenario where the manufacturer conducts its own testing of a product to verify compliance. The manufacturer may contract with a laboratory (second-party) to perform testing, however, it is the manufacturer that makes the claim. An example of self-declaration is a manufacturer’s “quality seal.”

2. One-time verification involves testing a product to verify compliance with a given standard at a specific time. This only provides information on a specific product sample tested and there are no requirements for on-going testing, plant audits, or market surveillance. Examples of one-time verification are the non-voluntary evaluations conducted by

Third-party certification is based on an independent body determining that a product complies with a standard. It includes initial verification of compliance, a follow-up system to ensure on-going compliance, and issuance of a certificate of compliance to the manufacturer and/or authorization for use of a certification mark on the product. Examples of third-party certification are, the National Nutritional Foods Association (NNFA) TruLabel Program, the NSF Certification Program, and the USP Dietary Supplement Verification Program.


Table 2. Summary of Dietary Supplement Evaluation Programs*

Evaluation Includes:
NNFA TruLabel
Label review
Test contents for quantity of ingredients
Test contents for contaminants
Inspect manufacturing
Test dissolution
Test disintegration
Requires membership in organization
Voluntary participation
Non-voluntary participation
Provides a certification or other mark on product label
Information about products available on website
Manufacturer pays a fee for service
Number of products certified as of 6/24/041,100450 companies2 >17,0002> 4005435

* Organizations are listed in alphabetical order. Label review generally refers to whether a product meets all the formal aspects required by FDA regulations and whether the identity of the product’s ingredient(s) contains what is claimed on the label. ‡ Plant inspection is available by request of company. Additional fee is required. § Also available in print in new book. || Fee is for voluntary testing requested by company.


Independent Programs for Evaluation of Dietary Supplements ( is a for-profit business founded in 1999 by Tod Cooperman, MD. (CL) offers two programs: a voluntary program and a non-voluntary program. The non-voluntary program ignited much of the interest in certifying dietary supplements to third-party standards when CL began selecting products off store shelves in 1999 to test the products for accuracy in labeling and to determine whether they contained any inappropriate levels of contamination. CL publishes online product reviews resulting from non-voluntary independent tests of multiple brands of specific supplements and nutritional products. CL evaluates both voluntary and non-voluntary products for identity strength (quantity), purity, and availability for absorption. Specific testing criteria vary by product and are selected on the basis of the relative importance of the product in the marketplace and a lack of any ongoing monitoring or reporting by government (of which there is none) or independent organizations. CL employs testing methods based on scientific and industry standards for analysis and publishes all its methods and criteria on its Web site. Unlike the non-voluntary testing in which CL chooses the products to be tested, the voluntary program allows manufacturers to request the specific products to be tested. All products are purchased on the open market through retail stores, on-line retailers, catalogues, or multi-level marketing companies. Products are not accepted directly from manufacturers. Products tested through either program that pass are eligible to use the CL approved quality product seal and are included on the list of approved supplements available on the CL Web site, which is available for a fee. Because some manufacturers are more interested in inclusion on “the list” than using the seal on their products, not all products approved by CL have its seal on the label.

For consumers and healthcare professionals this necessitates using the Web site or book (described below) to determine which products CL has approved. Products bearing the CL seal must be retested every 18 months to monitor compliance. CL also offers an Athletic Banned Substances Screening Program used by manufacturers to demonstrate that their products are in compliance with the Olympic Anti-Doping Code. This program was established at the request of the United States Olympic Committee. In addition to the product reviews and other information available on its Web site, which according to CL receives nearly 2 million visits per year, CL also offers testing of raw materials and private label products, issuing a certificate of analysis to products that pass its tests and posting these products on its Web site. CL also sells Technical Reports containing detailed analytical results for the products it selects for testing. Another report available from CL provides results of its Survey of Vitamin and Supplement Users, which shows how consumers evaluate, use, and rate different brands of supplements. More details about this report can be found at:

In addition to the results for more than 700 products currently on the CL Web site, the site has helpful information for consumers, including links to information about recalls and warnings and where to buy products. CL also publishes a free e-newsletter for consumers, although much of the data collected by the company is available to the public for a fee. One of CL’s helpful tools is its book,’s Guide to Buying Vitamins and Supplements: What’s really in the bottle? CL published this book in 2003, and it is authored by William Obermeyer, PhD, (former FDA natural products chemist and CL Vice President for Research) and Densie Webb, PhD, noted health writer. This book is convenient when shopping for products and contains a wealth of background information about intended uses of supplements as well as the results of CL’s testing. A revised edition of the book is planned for every two years.

National Nutritional Foods Association

The National Nutritional Foods Association (, an industry trade association representing health food stores, retailers, distributors, and manufacturers, offers two programs for the evaluation of dietary supplements: (1) the TruLabel Program which focuses on truth in labeling and content verification, and (2) the GMP Program which focuses on compliance with GMP. Regarding NNFA’s involvement in evaluating dietary supplements, David R. Seckman, NNFA Executive Director and CEO, states “Developing industry product standards is a typical function of associations and one that NNFA has proactively taken on. The reason is simple—an industry that demonstrates a willingness to self-impose standards not only can deliver better products to consumers, but can also help to convince government that self-regulation works” (e-mail from Tracy Taylor, NNFA Director of Public Affairs and Communication, June 30, 2004).

The NNFA TruLabel Program is a non-voluntary program for supplier members who manufacture dietary supplements and herbs under their own label.2 This includes companies that own their own product lines, but it does not include contract manufacturers that do not own the line of products they manufacture. Member companies are required to register their dietary supplement product labels in a confidential database and participate in random independent laboratory testing of their products. Should a test reveal a product or ingredient deficiency, the member company is contacted and given a brief period to correct the product or label. A company that fails to comply is expelled from membership and thus cannot exhibit at NNFA’s annual convention. More than 21,000 product labels are currently registered as part of the TruLabel program, the industry’s most expansive and successful self-regulatory program.2

The TruLabel Program does not offer manufacturers the opportunity to label their products as being in compliance with the program; however, a list of TruLabel test results is available free of charge on the NNFA Web site at science/bg_TruLabel.htm.

The NNFA GMP Certification Program is designed to verify compliance of member suppliers of dietary supplements with a standardized set of GMP developed by NNFA. This program is based on third-party inspections of member suppliers and comprehensive audits of their GMP programs in the areas of Personnel, Plant and Grounds, Sanitation, Equipment, Quality Operations, Production and Process Controls, and Warehouse, Distribution, and Post-Distribution Practices.2 As explained on the NNFA website:

This program ensures that all elements of the manufacturing process are reviewed to provide reasonable assurance that processes are sufficiently controlled so that products meet their purported quality. Member suppliers that meet minimum NNFA GMP standards and have received an “A” compliance rating after an NNFA GMP audit will be entitled to apply for certification and use of the NNFA GMP certification mark on the labels of their products. NNFA certification and display of the GMP certification mark demonstrate to retailers, consumers, and the public-at-large that products have been manufactured using good manufacturing practices and bring a means of self-assessment to the dietary supplement industry.2

In comparison to the TruLabel Program, this GMP program evaluates companies as a whole and does not evaluate each individual product. Audits to demonstrate compliance with this program are performed by one of two NNFA approved companies, both of which utilize former FDA staff to conduct the audits. A list of certified companies is available free of charge on the NNFA Web site at

On the surface, it might appear that NNFA, being an industry trade association, would not qualify as a legitimate “third party” because the organization, like all trade associations, exists primarily to promote and protect the interests of its industry members. When asked to clarify its position on this matter, NNFA President David Seckman wrote, “The fact that NNFA uses third-party auditors, with no affiliation to NNFA, means that our program can correctly be considered third-party certification. This has never been challenged and I believe ‘technically’ correct as NNFA cannot influence the outcome of the audits and certification requires an ‘A’ rating and the auditors’ recommendations. Additionally, the program requires that the auditing companies cannot have a business relationship with the companies they audit to ensure the integrity of the audits” (D. Seckman e-mail to M. Blumenthal, August 30, 2004).

NSF International

NSF ( is an independent, not-for-profit organization dedicated to protection of public health, safety, and the environment by developing national standards, providing learning opportunities through its Center for Public Health Education, providing third-party conformity assessment services, and offering risk management services while representing the interests of all stakeholders. The primary stakeholder groups include consumers, industry, and the regulatory community. NSF is widely recognized for its scientific and technical expertise in the health and environmental sciences. Its professional staff includes engineers, chemists, toxicologists, nutritionists, and environmental health professionals with broad experience in both public and private organizations. Although NSF is headquartered in Ann Arbor, Michigan, the NSF mark is recognized around the world. NSF was founded in 1944 with a mission of developing food equipment standards to improve the safety of food served in restaurants across the country. In the past 60 years, its standards and certification services have expanded to include a variety of products aimed at protecting consumers through the protection of food, indoor air, water, and the environment. In addition to dietary supplements, it offers programs for functional foods and beverages, non-GMO products, and organic foods. There are four main components of the NSF Dietary Supplements Certification Program: (1) verification that the contents of the supplement actually match what is printed on the label, (2) assurance that there are no ingredients present in the supplement that are not openly disclosed on the label, (3) assurance that there are no unacceptable levels of contaminants present in the supplement, and (4) compliance with GMP.1 According to Kathy Pompliano, NSF General Manager of Dietary Supplements and Functional Foods Programs, “the NSF program is unique because they offer consumers a means to make informed purchases across a variety of consumer products by looking for a single mark on products such as bottled water, functional foods, organic foods, water filters, foods equipment, and other items. NSF is the only certifier of dietary supplements that also provides certification of other products aimed at helping consumers live safer” (phone conversation with Kathy Pompliano, June 29, 2004).

NSF is recognized as a world leader in third-party certification and recently developed stringent criteria for product certification under the NFL/NFLPA (National Football League/National Football League and the Players Association) Supplement Certification Program. In addition to requiring NSF certification to NSF/ANSI 173-03 Dietary Supplements, which requires testing for common adulterants, microbiological contaminants, heavy metals, and pesticides, the program requires each product lot to undergo analytical testing to ensure the absence of any substances banned by the NFL/NFLPA. This program includes random off-the-shelf testing, annual GMP audits, Chain of Custody procedures, label and formulation change control, lot-by-lot product testing, and clinical study review. The benefit of finding the NSF mark on a product label is in knowing that the product met standards for both product content and GMP compliance. Because manufacturers that certify with NSF always put the NSF mark on their products, they are easy to identify. A list of products certified by NSF is available at

United States Pharmacopeia

Founded in 1820, the United States Pharmacopeia ( offers the Dietary Supplement Verification Program (DSVP). To date, USP has verified 543 products for various manufacturers (most of the products verified thus far are vitamin and mineral products, not botanicals). The USP seal appears on 50 million supplement labels on store shelves across the nation. USP verification is supplemented by its extensive efforts to educate consumers and healthcare professionals on how to choose dietary supplements. (The Web site at has more information on education programs, lists of verified products, and information brochures available to the public free of cost.)

The USP DSVP tests and verifies ingredients, products, and manufacturing processes of dietary supplements. The USP mark assures consumers that the product has passed five important quality tests indicating that the supplement (1) contains the ingredients listed on the label, (2) has the declared amount and strength of ingredients, (3) will break down easily in stomach fluids so the body can effectively absorb the nutrients in the supplement, (4) has been screened for harmful contaminants such as heavy metals, microbes, and pesticides, and (5) has been manufactured in safe, sanitary, and controlled conditions.3

According to Srini Srinivasan, PhD, Vice President, USP Dietary Supplement Verification Program, “We are a standard setting organization and we offer a verification program which is comprehensive because we are very thorough and we look for outstanding processes in order to assure consumers that the products verified are of high integrity and purity. This program rests heavily on GMP compliance to ensure quality” (S. Srinivasan e-mail to M. Blumenthal, August 20, 2004).

Dr. Srinivasan noted that the “USP also offers a voluntary program to verify ingredients used in the manufacture of dietary supplements. The use of USP-verified ingredients gives manufacturers participating in the dietary supplement verification program a head start in having their products verified.” He continued, “USP’s involvement in dietary supplements has been a key to the success of other programs through USP’s development of official, federally-recognized monographs for more than 900 vitamins, minerals, and many botanical and other products. In fact, manufacturers’ self-declaration of conformity to USP standards is commonly found on the labels of many supplements, which are not even part of USP’s voluntary third-party certification program.”

When selecting a dietary supplement, whether the individual is a consumer, researcher, or healthcare practitioner, finding a third-party mark can increase confidence in the product. The degree of confidence depends on the mark or seal and the needs of the individual making the selection. Individuals seeking the greatest confidence in the products they choose should select products that have been evaluated by a third-party organization that provides a comprehensive evaluation of products, including verification of the active ingredients (when known), evaluation of potential contaminants, truth in labeling, and compliance with GMP.

Marie Whybark is Adjunct Professor of Food and Nutrition at the University of Michigan and Madonna University and a consultant to NSF International.



1. United States Pharmacopeia 27-National Formulary 22. Rockville, MD: United States Pharmacopeia Inc., 2004.

2. National Nutritional Foods Association Web site, Available at: Accessed June 29, 2004.

3. United States Pharmacopeia Web site, Available at: Accessed June 29, 2004.

4. Cooperman T. E-mail to M. Blumenthal, August 10, 2004.

5. Srinivasan S. E-mail to M. Blumenthal, August 20, 2004.