Vitamins can get tricky. With recommendations varying from country to country, and different units of measurements being used, it can be hard to keep up, especially in Europe.

While many European countries opt for their own unit of measurement & vitamin D recommendations, in most European countries micrograms (µg) are considered the preferred unit of measurements. Click here for a summary of the UK vitamin D recommendations.

A microgram is a physical unit of measurement, measured at one-millionth of a gram or one-thousandth of a milligram[1] and is a part of the Popular Reference Intake (PRI), otherwise known as the Recommended Daily Allowance (RDA).

If you’ve ever been curious, µg comes from the Greeks after the Greek letter mu, where µ means “small”. Get it? µ = small, g = gram. Small gram. Microgram! I’ll stop now…

While µg is the proper symbol, it is not always typographically available, that is why you might see micrograms displaced as ug, mcg, or µg on labels.[2] Confusing, I know.

Another reason for all the abbreviations is to prevent one unit of measurement being mistaken for a different unit of measurement. For example, “mcg” and “µg” (for micrograms) can be mistake for “mg” (for milligrams), creating a 1000-fold overdose.[3]

Misread chart new

[4]Chart adapted from: U.S. Department of Health and Human Services

Mistakes happen, but many can be prevented. It is important to always refer to the Nutritional Information and Directions provided by the product (typically located on the side of the packaging), and speak to your health care professional before taking any new medications.


Photo from: Ddrops® One carton

For those living in the UK, specifically designed Ddrops products are available in the UK! Check-out our uk website for more information.

If you would like to look more into the differences between milligrams, micrograms, and international units for vitamins, the National Institute of Health’s Office of Dietary Supplements is a good resource to explore.[5]