What is 2000 IU? How to read units in dietary supplements (using Vitamin D3 and D3 + K2 as examples)

What is 2000 IU? How to read units in dietary supplements (using Vitamin D3 and D3 + K2 as examples)

On supplement labels you often see abbreviations and units such as IU, µg, mg, ml, and sometimes even “number of drops.” For anyone not working in medicine or pharmacology, this can be confusing.

In this article, we explain what these units mean, how to convert them, and how not to get misled when choosing a supplement — using Vitamin D3 and the D3 + K2 combination as examples.

 

1. IU – What is it?

IU (International Unit) measures the biological activity of a substance, not its weight.

It is mainly used for vitamins, hormones, and some medicines.

For Vitamin D3:

  • 1 µg (microgram) = 40 IU

  • 2000 IU = 50 µg

  • 400 IU = 10 µg

So, if the label says one serving contains 2000 IU of Vitamin D3, that means you’re getting 50 micrograms.

 

2. µg and mg – Micrograms vs Milligrams

  • 1 mg (milligram) = 1000 µg (micrograms)

    This is important — don’t confuse the two!

Example:

If a product contains 50 µg of Vitamin D3, that is not 50 mg. It is only 0.05 mg.

On labels you may see either unit, but for Vitamin D3 supplements, µg is most common.

 

3. ml – Millilitres, Volume not Dose

ml (millilitre) refers to the total volume of liquid, not the active ingredient.

For example, if you have Vitamin D3 drops in a 10 ml bottle:

  • 10 ml is the total fluid volume

  • The active ingredient (Vitamin D3) is dissolved in it

  • The dose depends on how many drops you take, not on the ml

 

4. Drops – Convenient but Check the Content

Vitamin D3 in drops is popular, but the amount per drop depends on concentration.

Example (3rd Element Nutrition actual product):

  • 6 drops = 2000 IU = 50 µg

  • 1 drop = ~333 IU = 8.3 µg

So daily dosage might look like:

  • 2 drops ~ 667 IU — aligns with EFSA’s recommendation for healthy adults

  • 6 drops = 2000 IU — often used for deficiency, but medical consultation is advised

 

5. What About Vitamin D3 + K2?

In combined supplements you’ll see two active units:

  • D3 → expressed in IU or µg

  • K2 → always expressed in µg (not IU)

Example:

  • 2000 IU Vitamin D3 (50 µg)

  • 100 µg Vitamin K2 MK-7

 

6. How to Choose the Right Dose?

EFSA (European Food Safety Authority) recommends:

  • 2000 IU is considered a higher dose — safe but better for deficiency or winter months

  • For everyday use, 1–2 drops of this strength is often enough

 

7. Summary – How Not to Get Misled

  • Always check if the label shows IU or µg
  • Check how many IU are in 1 drop
  • Don’t rely on ml — that’s just liquid volume
  • For D3 + K2, check both values separately
  • Adjust your dose to age, lifestyle, sun exposure, and medical advice

 

Final tip:

Always choose supplements that clearly show the active ingredients per serving, ideally with the conversion:

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