Our method
How We Choose Products
We use the same method for every product we recommend, and we publish it so you can check our reasoning.
What we look at, in order
- The form the research used. For creatine, that means monohydrate. For magnesium, it means a clearly stated amount of elemental magnesium in a well-absorbed form, with no hidden oxide "buffering."
- Independent testing. Supplements aren't approved by regulators before they're sold. We favor products listed in the NSF Certified for Sport, Informed Sport or USP Verified databases, where an outside lab checks each batch for label accuracy and contaminants. We look the product up in the certifier's own database rather than trusting the badge on the tub.
- Price per real dose. We compare cost per 5 g of creatine or per 200 mg of elemental magnesium, because price per tub or per "serving" hides how much you're actually getting.
- Nothing extra. No proprietary blends, unnecessary stimulants or ingredients at doses too small to matter.
We don't rank on taste, packaging or how many reviews a product has on Amazon.
How we grade evidence
| Grade | What it means |
|---|---|
| Good | Several controlled trials agree |
| Mixed | Trials point in different directions, or help one measure but not another |
| Early | One or two small trials; promising, not proven |
| Weak | Little or no support from controlled trials |
We link to the original study, not a press release, wherever we can. When a study was funded by, or run by people connected to, a supplement company, we say so on the page.
Hands-on testing
We don't run lab tests ourselves, and we won't claim to. Independent testing comes from the certification programs above, whose databases anyone can search.
What we can bring is long personal use. Tom, who writes the guides, has taken creatine monohydrate daily for about ten years and magnesium for much of each year. Where a guide includes first-hand experience, it's labeled as his and kept separate from what the research shows. We haven't personally used every product we list, and we don't pretend to have.
How we make money
When you buy through some links on this site, we earn a commission from the retailer. That never decides what we recommend: the ranking comes first, and we link to the products that pass it. Full details are in our affiliate disclosure.
Keeping things current
Prices and certifications change. We re-check every product at least every three months and update the date at the top of the page when we do.