How PillMath works
Official values
PillMath shows two sets of official values: EFSA (European Food Safety Authority) and the US Dietary Reference Intakes from the National Academies, which NIH uses. They differ because the panels used different data and methods. Neither is wrong; pick the one used where you live.
- PRI and RDA: enough for about 97 to 98% of healthy people.
- AI (adequate intake): used when data are too thin for a PRI or RDA. It is a best estimate, not a minimum.
- Safe upper limit (tolerable upper intake level, UL): the most per day, from all sources, that is unlikely to cause harm over the long term. Some limits (magnesium) count supplements only. For iron, EFSA gives a "safe level" instead. The site calls this the safe limit.
Study doses
A study dose is the amount used in a published trial or meta-analysis for a specific purpose. We prefer meta-analyses and large randomised trials, link every one, and say when a dose showed no benefit or harm. Study doses are not recommendations: they come with the people, product and time frame of that study.
Evidence grades
- Strong: a meta-analysis of randomised trials, or a large randomised trial (1,000+ people), with consistent results.
- Moderate: smaller randomised trials, meta-analyses with mixed or lower-quality data, or official guidance.
- Weak: one small trial, pilot data, or results that conflict.
The grade is about how sure we can be of the finding, not how big the effect is. "Strong" can also mean strong evidence of no benefit. Where later studies disagree, they are shown under "Other findings".
How new studies are added
Every week PillMath searches PubMed for new meta-analyses, systematic reviews and randomised trials on each supplement. An AI tool drafts a short summary, dose and grade from the abstract. A person reads each draft against the abstract, corrects it and approves it before it appears on the site. New studies show a "New" badge with the date they were added.
The maths
- Units: 1 g = 1000 mg = 1,000,000 µg. Vitamin D: 1 µg = 40 IU. Vitamin A: 1 IU retinol = 0.3 µg. Vitamin E: 1 IU = 0.67 mg (natural) or 0.45 mg (synthetic).
- Mineral salts: if your label gives the salt weight (for example 500 mg magnesium citrate), PillMath uses a typical elemental share. When the label states the elemental amount, use that.
- Folate: folic acid and methylfolate count about 1.7 times more than food folate (DFE). The upper limit uses the plain amount.
- Rounding: capsules and softgels are rounded to whole units, tablets to halves, scoops and liquids to one decimal. If you need less than one a day, PillMath suggests a number per week.
- Averages: every-other-day or weekly doses are averaged per day before comparing with daily values.
Limits
PillMath covers healthy adults (18+). It does not know your diet, blood tests, medicines or health conditions, so it cannot tell you what you personally need. Supplements are not tested like medicines and labels can be inaccurate.
Updates and corrections
Values were last checked on November 12, 2026. When EFSA or NASEM update a value, we update the site.