A closer look.
A clearer choice.
Make sense of supplement labels, compare the details, and find the questions worth asking.
Less guesswork.
More understanding.
What would you like
to understand?
Start with a question.
Leave with a better way to compare.
What’s actually
in this bottle?
Serving sizes, ingredient amounts, and the details behind the front label.
Learn the essentials02 / COMPARE THE DETAILSHow are these
options different?
Ingredient forms and real product labels, explained side by side.
See the comparisons03 / CHECK THE NUMBERSWhat does a
serving really cost?
Turn a bottle price into a useful number with our free calculator.
Try the calculatorSame ingredient.
Different details.
Two softgels. Three capsules. One capsule. A serving can look very different—even when every bottle says magnesium citrate.
See the full comparisonManufacturer-label comparison. Not laboratory tested by SD.
Nature Made
250 mgper 2 softgels
NOW
400 mgper 3 capsules
Life Extension
100 mgper 1 capsuleNOW’s 400 mg serving exceeds the general adult supplemental upper limit of 350 mg/day. Read the safety context.
A few things worth knowing.
Citrate or glycinate?
Look beyond the form name to elemental magnesium, serving size, tolerance, and the limits of health claims.
Read the guideVitamin D2 vs. D3
Understand the two forms, convert micrograms and IU, and compare products without assuming more is better.
Read the guideWhat an omega-3 label really tells you
Why the total fish oil amount is different from EPA plus DHA, and how to compare omega-3 labels fairly.
Read the guide
A small checklist.
A better starting point.
Eight things to check before buying a supplement. Keep it on your phone or print a copy for the next time you’re comparing labels.
Open the free checklistNo signup needed. No product recommendations hidden inside.Every option gets
the same close look.
We explain what a label says, show our sources, and tell you what a comparison can’t establish. Brands cannot buy a higher position in our guides.
Read how we work