What are vitamin D supplements?

Vitamin D is available in different types of supplements. Which supplement and how much to take will depend on your reasons for taking a supplement. Talk to a health professional about your needs.

Active ingredients in vitamin D supplements

The active ingredient is the chemical that makes the medicine work. All over-the-counter vitamin D supplements contain the active ingredient colecalciferol (pronounced kol-eh-kal-sif-eh-rol) — which may also be spelt cholecalciferol.

Some supplements combine vitamin D with other active ingredients such as calcium, magnesium, copper, zinc and boron. You will find the active ingredient(s) written on the packaging or label.

Multivitamins, halibut and cod liver oil don’t contain enough vitamin D to treat vitamin D deficiency and they may provide too much vitamin A.


Supplements containing vitamin D come in different strengths. The strength is written on the front of the packaging and is usually expressed as international units (IU). It is sometimes written as micrograms (mcg or µg).

The amount of vitamin D in tablets and capsules ranges from 100 IU to 1000 IU, and is sometimes combined with other active ingredients.

Your doctor will let you know the strength that’s right for you.


Over-the-counter supplements containing vitamin D come in different forms including capsules, tablets, dissolvable tablets, chewable tablets, powder and liquids. Choose the formulation that best suits your personal preference.

How much to take and when

The dose will depend on the strength of the medicine, the number and type of active ingredients it contains, and your own situation and reason for taking Vitamin D. Your doctor or pharmacist can advise on what is appropriate for you.

Vitamin D supplements can be taken at any time of the day, with or without food. However, taking your medicine at the same time each day will have the best effect. It will also help you remember when to take it.

Download our 'Vitamin D tests and deficiency' fact sheet to find out if you are at risk of deficiency, how to improve your vitamin D levels, and whether you need a vitamin D test.

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