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Questions to ask suppliers about their products
January 1999

The following questionnaire takes a comprehensive look at all areas that affect quality in the process of manufacturing dietary supplements. By asking manufacturers any of these questions, you will be contributing to enhanced quality in the dietary supplements that you consume.

Raw Ingredients

1. What are the sources of your ingredients?

  • Do you grow your own ingredients exclusively?
  • Buy directly from growers or producers, buy from wholesalers, or a combination of sources?
  • What criteria do you use in selecting your sources?

2. How do you ensure that ingredients are free of impurities and contaminants? How do you determine their level of potency?

  • Do you test ingredients in an in-house lab?
  • Obtain certifying documents from growers/producers?
  • What steps do you take to evaluate the accuracy of supplier's certifying documentation?

3. If ingredients are organically grown or "wildcrafted," how do you assess source areas in terms of natural state and freedom from toxic influence?

4. Are your ingredients synthetic or natural in origin? How do you differentiate between the two?

5. Do you require statements of non-irradiation from botanical suppliers?

6. If you produce vegan products, please describe the manufacturing process for gelcaps.

7. Please describe the composition of the filler powders and/or extract solutions used to produce your products.

8. Certain substances, such as corn, milk, and soy, can cause allergic reactions in certain individuals. When such substances are used in your products or formulations, how do you highlight their presence?

Warehousing And Storage

9. Describe the methods and procedures you use for storing raw ingredients before processing and how you store final products before shipping.

  • HVAC controls such as air conditioning
  • Composition of storage containers
  • Storage time limits (shelf life) in warehouse/at distributor, etc.

Manufacturing Processes

10. Describe the general nature and methods of your manufacturing process. If you are a larger organization, please include the following information:

  • What types of machinery do you use?
  • Do you run single or multiple production lines? Work cell or straight line? Please describe.
  • To what extent are your operations automated? Alternatively, do you engage in "craft" manufacturing rather than continuous operations?
  • Do you employ degreed industrial, chemical or pharmaceutical production engineers?
  • Have you implemented an enterprise resource planning or supply chain management system?

11. Describe the nature and scope of your cleaning programs.

  • Duration of machine/device/line use between cleanings
  • Types and strengths of cleaning substances used
  • Precautions and tests used to ensure products are free of cleaning substances

12. Do you use a lot-tracking system that can identify all the ingredient sources of a particular bottle? If this system is implemented in software, please provide name of supplier and years since implementation.

13. How do you ensure consistency of potency levels from batch to batch or tablet to tablet?

14. What level of accuracy of individual dosage do you aim for?

  • Within 10% of the labeled amount? 5%? 1%?
  • Some other type of range?
  • Does this accuracy range vary by product?

15. Do your product labels carry expiration dates? If so, how do you determine the useful shelf life of specific products? Do your product labels include information about beneficial storage conditions that will help maintain or extend the product's useful shelf life?


16. Please provide an overview of your testing programs. Explain how you guard against or test raw ingredients and/or final products for the presence of:

  • Heavy metals, including lead
  • Herbicides, pesticides, and other agricultural chemicals
  • Microbial contaminants
  • Organic and petroleum chemical contaminants
  • Steroids and antibiotics

17. Are materials and product testing performed in-house or by one or more independent labs? Please describe the staffing level and equipment complement of any in-house facilities. If you use external testing resources, please provide nature of services.

18. At what stages of the manufacturing process do you test your products?

  • when raw materials arrive?
  • after manufacturing but before packaging?
  • after packaging?

Efficacy Research

19. What determines which formulations and/or substances you produce?

  • What guides the choice of ingredients you use in your products?
  • How do you determine levels of ingredients needed to produce a clinically effective dose?
  • Do you perform your own research or undertake periodic literature reviews?
  • What professional credentials or life-experience credo are represented by your product development group?

20. Do you provide customers with scientific information about the clinical effectiveness of specific ingredients in your products?

  • What kind of information do you provide?
  • Do you maintain copies of published clinical studies for free distribution? Do you undertake comparative analyses of scientific research?
  • Do you include information about negative findings as well as positive?
  • Have the health benefits of the ingredients in your products been published in a monograph or peer-reviewed journal?

Other Considerations

21. What precautions do you take to make sure that consumers do not accidentally take an excessive/toxic dose?

  • Are your products accompanied by cautions regarding toxic-dose levels?
  • Do your product labels carry contraindications?
  • Do your product labels describe both appropriate and excessive dosages?
  • Do you have an internal system for reporting and/or investigating adverse events? Do you report adverse incidents to a national compiling/reporting group?

22. Describe your overall GMP program(s) in relation to meeting or exceeding any of the following standards that apply to your company:

  • food-level GMPs
  • FDA's current GMP guidelines for dietary supplements
  • NNFA's GMP program requirements
  • CRN's GMP standards
  • OTC-level GMP standards
  • Pharmaceutical-level GMP standards
  • Other GMP standard?
  • If you do not currently participate in a GMP program, do you anticipate entering one in the near future?

23. Describe your participation in any of the following programs or eligibility for any of the following certification seals:

  • ConsumerLab's certification seal
  • Institute for Nutraceutical Advancement botanical testing
  • NNFA's TruLabel program
  • Paracelsian's BioFIT certification
  • USP disintegration and/or dissolution standards
  • Other?

24. Does your company belong to any trade associations? If so, which one(s)? How long has your company been a member of each?

Company Background and Context

25. Is your company independently owned or part of a larger organization? If the later is the case, please describe the nature of the owning company's business.

26. What is the overall size of your company? What is your approximate

  • number of employees?
  • number of products?
  • gross annual sales?
  • publicly-held or private company


previous page Supplement production starts with either mining or growing the materials from which supplements are made.

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Supply chain: From raw materials to consumer shelves


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(c) Copyright 1999-2003 Dietary Supplement Quality Initiative. For permission to reprint, please contact our editor.