Supplement Buying Guides
Every supplement we cover is scored on the same 6-metric rubric — so you can see exactly why one magnesium, probiotic, or multivitamin ranks ahead of another. Read the scoring methodology →
Best Magnesium Supplements, Scored on a Public Rubric
We scored 7 top-selling Amazon magnesium supplements on a public 6-metric rubric — third-party testing, form, value, transparency, and more.
Best Probiotic Supplements, Scored on a Public Rubric
Side-by-side scoring of six probiotics on our 6-metric rubric: named strains, CFU dose, third-party testing, shelf-stability, and value.
Best Fish Oil Supplements, Scored on a Public Rubric
We scored six fish oil supplements on our 6-metric rubric: EPA/DHA dose, oxidation, third-party testing, and value per gram of omega-3.
Best Vitamin D Supplements, Scored on a Public Rubric
We scored six vitamin D3 supplements on our 6-metric rubric: dose accuracy, K2 pairing, third-party testing, and value per IU.
Best Collagen Peptides, Scored on a Public Rubric
Six top-selling collagen peptide supplements compared on our 6-metric rubric — molecular weight, source, third-party testing, and value.
Best Ashwagandha Supplements, Scored on a Public Rubric
Five ashwagandha supplements scored on our 6-metric rubric: extract type (KSM-66, Sensoril), withanolide content, and third-party testing.
Best Multivitamins, Scored on a Public Rubric
Six multivitamins compared on our 6-metric rubric: bioavailable forms (methylated folate, MK-7, methylcobalamin), third-party testing, and value.