DeepReviews

How we review supplements

Last updated .

Every DeepReviews review follows the same process, and each one tells you exactly what we did.

Our process

  1. We read the marketing. We go through the sales video, product page and checkout, and list every claim about results, ingredients, price and guarantees.
  2. We find out what’s in the product. We use the Supplement Facts label when we can get it. When a brand doesn’t disclose its doses, we say so in the review.
  3. We check the research. For each advertised ingredient, we look for human studies, starting with systematic reviews and meta-analyses, and for guidance from government health sources such as the NIH and FDA. We link to what we use.
  4. We check safety. We cover common side effects, drug interactions and who should avoid the product.
  5. We check the money. We record the real prices on the checkout, work out the cost per day, and read the shipping and refund terms.
  6. We look at customer reviews. We look for independent reviews we can verify. Testimonials on a brand’s own pages are advertising, and we treat them that way.
  7. We say what we didn’t do. If we didn’t test a product ourselves, the review says so near the top.

How we rate the evidence

Our Review facts panel rates the evidence for what each ingredient is advertised to do, not for the ingredient in general.

None found
We found no human studies supporting the advertised effect.
Limited
A few small human studies, or results that are inconsistent or barely significant.
Modest
Several human trials, pooled in reviews, show a small but consistent effect.
Good
Consistent, meaningful effects in well-designed human trials.
Strong
Large, high-quality trials with clear and consistent results, the level expected of approved medicines.

A rating describes the ingredient at the doses studied. If a product doesn’t disclose its doses, we can’t tell whether it matches the research.

Independence

We earn commissions from some links. Brands can’t pay for a review, a better rating or the removal of criticism, and every review lists downsides and alternatives. Read our affiliate disclosure.

Updates and corrections

We update reviews when prices, formulas or policies change, and the date at the top shows the last update. If you find an error, email contact@deepreviews.site.