Short version: we don’t run a lab, and we don’t get free products. What we do is slower and less glamorous. We read the research, read the labels, look up every certification in the certifier’s own records, check FDA recalls and warning letters, and then write down what we found with links so you can check it yourself.
This page explains the two ratings you’ll see on our reviews: the SWA Score, which rates a product or brand, and the Evidence Grade, which rates the research behind what people buy it for. They answer different questions, so we keep them separate. A brand can make a clean, accurately labeled product for a purpose the research doesn’t support well, and we think you should know both things.
What we check before we score anything
- The research. Randomized trials, systematic reviews and meta-analyses on PubMed and Cochrane, plus fact sheets and guidance from the NIH Office of Dietary Supplements, the FDA, the CDC and medical bodies.
- The label. Every Supplement Facts panel: the form of each ingredient, the dose per serving, the maximum daily dose the label allows, and how that compares with official upper limits.
- Certifications. We search the certifier’s own public database (for example NSF Certified for Sport or USP Verified) rather than trusting a logo on a product page. If we can’t confirm a claim, we say so.
- Transparency. Whether the company publishes batch test results (Certificates of Analysis) or will send them on request, and how clearly it explains where and how products are made.
- Track record. FDA recalls, warning letters and enforcement actions, and how long ago they happened and what they were about.
- Price. The cost per serving and, where it helps, per useful unit (for example per 100 mg of magnesium), checked on the date shown in the review.
The SWA Score (out of 10)
We rate five things from 0 to 10, then combine them with the weights below. Quality gets the most weight because a supplement that doesn’t match its label isn’t a bargain at any price.
| What we rate | Weight | What earns a high mark |
|---|---|---|
| Quality and independent verification | 35% | Audited manufacturing, plus product-level testing by an outside certifier that we could confirm in its database |
| Label and dose sense | 20% | Useful forms and doses, clear directions, and labels that don’t nudge people past official upper limits without a reason |
| Value | 20% | A fair price per serving compared with similar products of similar quality |
| Transparency | 15% | Batch test results published or easy to get, and clear sourcing information |
| Track record | 10% | No recent recalls or warning letters, especially for the products we’re reviewing |
| SWA Score | 100% | Weighted average, rounded to one decimal place |
Every scored review shows the five marks in a table so you can see where the number came from and re-weight it for yourself. If you’re a competing athlete, for example, independent verification may matter far more to you than price.
What the numbers mean
- 8.0 to 10: Easy to recommend. Few caveats.
- 7.0 to 7.9: Good, with caveats. Worth buying if the caveats don’t apply to you.
- 6.0 to 6.9: Right for some people. Real strengths, but real trade-offs you should weigh.
- Under 6: Hard to recommend. We’ll usually point you somewhere else.
We don’t hand out 10s. A perfect score would mean independent testing on every product, public batch results, sensible doses, a clean record and a fair price, and we haven’t found a brand that does all of that yet.
The Evidence Grade (A to D)
The Evidence Grade is about the nutrient or product type, not the brand. It answers one question: for this specific use, how good is the research?
- A, strong: consistent results across good randomized trials or systematic reviews, or clear guidance from major health bodies.
- B, moderate: some good trials, but with limits: small, short, or mixed results.
- C, limited: a few small studies, mostly low quality, results only in specific groups, or a plausible mechanism that big trials haven’t confirmed yet.
- D, weak or none: mostly theory, animal studies, testimonials or marketing, or good trials that looked for a benefit and didn’t find one.
The same nutrient can earn different grades for different uses. Vitamin D is a good example: it gets an A for correcting a low blood level, and a D for preventing cancer or heart disease in healthy adults who aren’t low, because the large VITAL trial looked for that benefit and didn’t find it.
What we don’t do
- We don’t claim to have lab-tested anything. If we ever use a product hands-on, the review will say what we did, for how long, and what we couldn’t judge.
- We don’t accept payment for coverage or for a higher score, and brands don’t see reviews before they’re published.
- We don’t let affiliate status into the score. Whether we earn a commission from a brand isn’t one of the five things we rate.
- We don’t give personal medical advice. Scores tell you about a product, not whether it’s right for your body or your medicines.
Updates and score changes
Each review shows the date we last checked it. Prices, certifications and formulas change, so we re-check scored reviews regularly and whenever there’s a recall, a safety warning or important new research. If a score changes, we note the old score, the new one and the reason at the bottom of the review.
Spotted a mistake or a study we missed? Please tell us on our Contact page. You can also read our Editorial Policy, our Affiliate Disclosure and our Medical Disclaimer.