Background Research

• Before choosing a supplement company, the best thing to do is research the brand you're considering. Call the company to find out how it certifies its products and whether it follows Food and Drug Administration guidelines for manufacturing dietary supplements.
  
  

Ingredient Comparison

• Similar supplements from different companies usually contain almost the same ingredients, although there are variations. Check the United States National Library of Medicine Dietary Supplements Labels Database for more information on companies, brands and supplement ingredients.
  
  

Product Certification

• Although supplement manufacturers aren't required by law to certify their products, the more reputable ones do. Independent organizations, such as ConsumerLab.com, test various foods, water products and supplements for contamination and certify the ones that pass. They then publish public reports on their findings.