Supplements: what is actually evidence-based?

The supplement aisle is full of pretty bottles promising hormone balance. The NHS and the BDA agree that most people can get what they need from a varied diet, and that most people do not need supplements. There are a few important exceptions.

Well supported

• Vitamin D: the NHS says everyone should consider 10 micrograms a day in autumn and winter, when UK sunlight is not strong enough. If you are rarely outdoors, cover most of your skin outside, or have dark skin (for example African, African-Caribbean or south Asian backgrounds), consider taking it all year.
• Folic acid: 400 micrograms a day if you could get pregnant or are trying, taken before conception and until 12 weeks of pregnancy. Some people are advised a higher dose, so speak to a doctor.
• Iron: only if a blood test shows you need it, as advised by a doctor.

Some evidence, not a sure thing

• Calcium, vitamin B6 and zinc show some benefit for PMS in small trials, but the NHS says there is not much evidence that PMS supplements work. Our PMS supplements read goes through the details and the safe limits.
• Magnesium may help some people, but the evidence is limited.