Supplement
Vitamin D for women
Vitamin D contributes to the maintenance of normal bones and muscle function and to the normal function of the immune system. The NHS advises that adults in the UK consider a daily 10 microgram (400 IU) supplement, particularly in autumn and winter. Most D3 is from lanolin, but vegan D3 from lichen is available. Do not exceed label amounts without advice.
What it does
Vitamin D helps the body absorb calcium and supports several normal functions. The EFSA-authorised roles include:
- Vitamin D contributes to the maintenance of normal bones.
- Vitamin D contributes to the maintenance of normal muscle function.
- Vitamin D contributes to the normal function of the immune system.
- Vitamin D contributes to normal absorption and utilisation of calcium.
In the UK, where sunlight is limited for much of the year, the NHS treats vitamin D as the one supplement many adults should genuinely consider, rather than a nice-to-have.
Who it is for
Vitamin D is relevant across every life stage. The NHS recommends it in pregnancy and while breastfeeding in the postnatal period, and it matters for bone health through perimenopause, menopause and the senior years. People with little sun exposure or darker skin may benefit year-round.
What to look for when buying
- The NHS advises that adults in the UK consider a daily 10 microgram (400 IU) vitamin D supplement in autumn and winter; some people are advised to take it all year.
- Check whether it is vitamin D3 (the form usually recommended) and whether the source is vegan if that matters to you, since most D3 is from lanolin.
- Compare the amount in micrograms (mcg) and IU; 10 micrograms equals 400 IU.
- Higher-strength products exist, but do not exceed label guidance without advice; speak to your GP or pharmacist, especially in pregnancy.
Named UK brands to compare
These are real UK vitamin D products, including spray, capsule and vegan options. Links are affiliate placeholders and are being wired in; we add a buying link only once it is live.
For a ranked head-to-head, see our roundup of the best vitamin D supplement in the UK. If you are weighing it against a broad blend, see do you need a multivitamin?.
Frequently asked questions
How much vitamin D should I take?
The NHS advises that adults consider a daily 10 microgram (400 IU) vitamin D supplement, particularly in autumn and winter when sunlight is limited. Some people are advised to take it all year. Follow current NHS guidance and do not exceed label amounts without advice.
What is the difference between 10 micrograms and 400 IU?
They are the same amount expressed two ways: 10 micrograms (mcg) of vitamin D equals 400 international units (IU). Labels may use either, so it helps to know the conversion when comparing products.
Is there a vegan vitamin D?
Yes. Most vitamin D3 is derived from lanolin (sheep’s wool), but vegan D3 made from lichen is available, and D2 is plant-derived. If a vegan source matters to you, check the label, as not all products state it clearly.
Can you take too much vitamin D?
Yes. Very high doses over time can be harmful, which is why the NHS advises not exceeding recommended amounts unless a doctor tells you to. If you are pregnant, take other medication or have a health condition, speak to your GP or pharmacist about what is right for you.
This is information, not medical advice, and is not a substitute for a registered clinician. Always read product labels and speak to your GP or pharmacist before starting a supplement.
Editor, Her Vitals
Oliver leads Her Vitals's editorial coverage of women's life-stage health and supplements. He curates and reviews existing branded products across trying to conceive, pregnancy, postnatal, perimenopause, menopause and the senior years, weighing what the evidence supports against guidance from bodies such as EFSA, the NHS and NICE, and is clear that the content is information rather than medical advice.
Last reviewed: 8 June 2026