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Plain-English explainers on reading supplement labels, backed by the numbers from every US label in the NIH DSLD.
Every number is computed from the label data and linked to its source. Subscribe with the RSS feed.
Label reading
Magnesium oxide, citrate or glycinate? What the form on your label tells you
Nearly half of magnesium supplements never name their form, and 1,000 mg of the compound is not 1,000 mg of magnesium. Here is how to read the label.
September 20, 2026 · 6 min read
Label reading
Proprietary blends: the supplement label line that hides the dose
More than one in four US supplement labels lists a proprietary blend. Here is what the rules require, what they let brands keep secret, and how to read one.
September 20, 2026 · 6 min read
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