Not All Vitamins Are Created Equal: Why Your Supplements Might Be Failing You

9. Brand Transparency and Company History
Companies that invest in Research and Development (R&D) usually publish their test results transparently. If a brand provides no information about the source of its raw materials, it is best to be skeptical. Leading brands usually provide a "Certificate of Analysis" (COA) for their products upon request, which proves the authenticity of the goods.