Independent supplement ratingsUS and Canada · Updated weekly
A ratings desk for a category that has spent thirty years grading its own homework.
A ratings desk for a category that has spent thirty years grading its own homework.
Every product in our rankings gets a full review: the label against the research, the price per serving, and a plain verdict. Filter by category.
Every review answers four questions in the same order. What does the label actually contain, in the units that matter — elemental magnesium rather than compound weight, standardized extract rather than raw root. How does that dose read against the trials the ingredient is sold on. What do verified buyers report, taken from a listing we link to. And what does one serving cost, which is the only price comparison that survives different tub sizes.
The score out of ten falls out of those answers. It is not a vibe, and it is not adjusted after the fact to make a ranking read better.
We do not accept free product in exchange for coverage, we do not let a brand see a review before it publishes, and we do not sell a position. Brands can buy a clearly labelled placement through For Partners, and that placement never touches a score. Some links here are affiliate links; a product loses points for a thin formula whether or not we earn anything when you click.
A low score usually means one of three things: the doses are hidden inside a proprietary blend, the actives are present at a fraction of the studied amount, or you are paying a premium for a form the body absorbs badly. Each review says which. A product can be perfectly safe, perfectly legal and still be a poor way to spend forty dollars, and that is most of what we find.
Reviews are grouped by category on the rankings, and the ingredients behind them are broken down in the ingredient index.