Vitamin and mineral units on labels: micrograms, milligrams, IU, and the conversions that trip people up

A surprising number of supplement labeling errors come down to units. A vitamin declared in international units when the EU wants micrograms, a vitamin A figure that doesn't account for the difference between retinol and beta-carotene, a folate number that ignores the conversion to dietary folate equivalents — these are easy mistakes with real consequences, because they make the declaration and the %NRV wrong. Getting units and conversions right is unglamorous and essential.

IU versus metric units

Some vitamins — A, D, E — have historically been measured in international units (IU), but EU labeling uses metric units (micrograms or milligrams). So a vitamin D supplied or specified in IU has to be converted to micrograms for the EU label, and the conversion factor differs by vitamin. Carrying an IU figure straight onto an EU label, or using the wrong factor, produces a wrong declaration.

Vitamin A and retinol equivalents

Vitamin A activity comes from preformed retinol and from provitamin carotenoids like beta-carotene, which contribute differently. Expressing vitamin A correctly — as retinol equivalents — means weighting the carotenoid contribution by its conversion factor, not just adding the raw amounts. A vitamin A figure that treats beta-carotene as equivalent to retinol overstates the real activity.

Niacin and folate equivalents

Similar logic applies to other nutrients. Niacin is expressed as niacin equivalents, accounting for the contribution from tryptophan where relevant. Folate is expressed as dietary folate equivalents, with folic acid and food folate contributing differently. Declaring these without the proper equivalent calculation gets the number — and the %NRV — wrong.

Why it cascades

A unit error doesn't stay contained: the declared amount feeds the %NRV, which feeds whether a claim's qualifying threshold is met. So a wrong unit conversion can simultaneously misstate the amount, miscalculate the percentage, and wrongly indicate a claim is or isn't supported. One conversion error ripples through the whole declaration.

Handle conversions in the system

Because these conversions are defined and repeatable, the reliable approach is to hold each nutrient with its correct unit and conversion logic, so the system expresses every nutrient in the right unit and equivalent for the label — IU to micrograms, retinol equivalents, niacin equivalents, dietary folate equivalents — consistently across every product. Doing them by hand per label is where the errors live.

This is general information, not regulatory or legal advice. Requirements differ by market and change over time, so confirm current rules with the relevant authority or a qualified regulatory expert before relying on them.

Where Lemoniq fits

Lemoniq holds each nutrient with its correct units and conversion logic — IU to metric, retinol, niacin, and dietary folate equivalents — and expresses every nutrient correctly on the label and in the %NRV, consistently across products, so a unit conversion never quietly breaks a declaration or a claim.

The takeaway

Nutrient units and equivalents — IU versus metric, retinol, niacin, and folate equivalents — are a quiet but cascading source of labeling errors, because a wrong conversion misstates the amount, the %NRV, and claim eligibility together. Handling conversions consistently in the system is what keeps every declaration right.

Lemoniq expresses every nutrient in the right unit and equivalent, automatically. See how it works