You can try to ask a manufacturer or distributor for the “country of origin” of ingredients in its product, but it may not be provided. Be aware that manufacturers may change the source of an ingredient over time. Even if you learn that an ingredient is from China -- as many are – ingredient suppliers typically sell more than one version of an ingredient, each differing in quality and cost. It is up to the company making the final product to decide what grade of ingredient to purchase and use.
For us at ConsumerLab.com, the most important question is not where a product or its ingredients originate, but “what’s really in that product?” That is, does the supplement contain the listed ingredient at the claimed amount, without contamination (from lead and other heavy metals, etc.), in an unspoiled condition, and will tablets/caplets properly break apart to release the ingredients? These are issues which affect supplement quality, regardless of the country of origin. (You can read how we test each type of product at How Products Were Evaluated.) We also check that product labeling is clear, and we identify toxicity risks with ingredients in the amounts provided.
So, although it may not be possible to find out the geographic origin of the ingredients in a supplement, you can use our information to find out if a product provides what it claims and what you want.