Our sources & methodology

Why NIH ODS is our primary source

Our reference of first resort is the NIH Office of Dietary Supplements (ODS) — specifically its Health Professional fact sheets. Three reasons. First, it's a U.S. federal science office with no supplement to sell, so its numbers aren't marketing. Second, its fact sheets carry the actual reference values — Recommended Dietary Allowances, Adequate Intakes, and Tolerable Upper Intake Levels — with the nuance (age, sex, pregnancy) intact. Third, every fact sheet is public, so when we cite one you can click through and check us in thirty seconds.

For food-pattern context — what a realistic plate looks like, not just the nutrient math — we also draw on the Harvard Nutrition Source.

One dataset behind every number

Here's the part most sites get wrong: they retype numbers into each article, and the copies drift. We don't. All intake and upper-limit values on this site live in a single structured dataset transcribed from the NIH ODS fact sheets, with the source URL stored next to every nutrient. The Supplement Safety Checkerrenders its entire comparison table straight from that dataset, and the doses quoted inside our guides are pulled from the very same records at build time — so “2.4 mcg of B12” in an article can't quietly disagree with the checker. One dataset, one truth, every page.

How a claim gets into a guide

Guides are drafted with AI assistance (our honestly-disclosed writer, Vita), fact-checked against the cited ODS sheets, and then reviewed by registered dietitians on a rolling cycle — how we reviewcovers that process. Claims that can't be traced to a source don't ship, and we deliberately avoid prescriptive dosing (see the editorial policy).

How often we re-check

Numbers rot quietly, so freshness is a rotation, not a resolution: every published page re-enters a refresh queue on a 60-day cycle, where we re-open the cited fact sheets, re-verify the values against the dataset, and bump the page's updated date. Two things can pull a page forward ahead of its slot: NIH updating a fact sheet we cite, or a reader/reviewer flagging an error — corrections don't wait for the rotation. Independently of this, the dietitian review cycle touches pages roughly every three days.

The limits of our sources — said plainly

Reference values are population-level science; they describe healthy adults in general, not you in particular. That's why our pages present nutrient gaps as “likely,” never as diagnoses, and why no page on this site replaces a blood test or a clinician. If a number matters for a health decision, verify it at the source we link — then take it to your provider.