Do you find vitamin D supplement labels tricky to understand?

You're not alone. Some labels use micrograms, others use international units, and some show both. Once you know how the two connect, comparing products becomes much simpler.

Two units, same vitamin

Vitamin D is measured in micrograms (mcg) or international units (IU). 1 mcg is the same as 40 IU.

For example: 25 mcg and 1,000 IU are exactly the same amount.

Want to check your own label? Try our vitamin unit converter.

The forms you’ll see

• Colecalciferol (vitamin D3)
• Ergocalciferol (vitamin D2)

Daily nutritional targets

These targets assume you get little or no sun.

• Adults 19–50 years: 5 mcg (200 IU)
• Adults 51–70 years: 10 mcg (400 IU)
• Adults over 70: 15 mcg (600 IU)

In Australia, the upper limit is 80 mcg (3,200 IU) a day from all sources. Some imported products follow a higher US limit, so it’s worth checking the amount.

Taking 1000 IU? Read Is 1000 IU of vitamin D enough?

Three quick checks before you buy

1. Note whether the label uses mcg or IU, and convert if you need to.
2. Multiply by the number of capsules or drops you’ll take each day.
3. Look for an AUST L or AUST R number. It shows the product is on the TGA register.

Your pharmacist or GP is always happy to help you work out what’s right for you.

Daily nutritional target

Upper limit

Common forms

Conversion factors

Reference details

Rated products containing this nutrient