— Walmart.com: Sold by “Double Wood Supplements” — Other sites: Vitacost.com Dr. Mercola — Own website — Sold on Amazon.com or Walmart.com? — Other sites:iHerb.com*, Fullscript.com, Swansonvitamins.com Emergen-C — Amazon.com†: Sold on "Emergen-C" store. In Transparency ...