Is Nature Made third party tested?

Partly: 22 of the 34 products we track. Of the 34 Nature Made products we track across 8 categories, 22 are confirmed at the package, in USP’s directory with the mark on the label, 1 matches a row in USP’s directory not yet confirmed for the package we price and 11 appear in no database we searched.

USP names a product and a strength, not a whole brand, and puts its mark on the label. So “Nature Made is USP Verified” can be true of one bottle while the strength or the line beside it has no row in USP's directory. Each row below says which, and a package counts only when the directory row and the mark on its own label both hold.

No listing is an absence in a database, not a failed test: most supplements have never been independently tested. NSF Certified for Sport, the Informed programs' published product lists, the IFOS directory and USP's directory are each read in full. Each product page names the day.

Every category we compare: the home page. Every question we answer: the question index.

What this rests on: prices we last recorded at the retailer named on each product page, which go stale, and each page says when it was checked; the products we track, not every product sold, and Amazon and Walmart are not among the stores; listings and labels read at the source, each linked from the page. Found an error? Tell us. The full method: How we compare.