Best supplements for women: what you need in your 20s, 40s and over 50

How this section works

We don’t rate the bottle labelled “for women”. Instead, we look at the individual nutrients women need more often: the daily need, the upper limit, who should avoid each one and how to find the right form on iHerb.

Find your option: women's health

Pick your situation to see what's been studied and where to start

Your situation

Trying for a baby Heavy periods 50+ and menopause Vegetarian or vegan

What makes sense

Folic acid and vitamin D

Start folic acid before you conceive and keep taking it until week 12. Avoid vitamin A (retinol) supplements and fish liver oil in pregnancy.

Dose: 400 mcg folic acid and 10 mcg vitamin D a day (NHS)

If you have diabetes or take epilepsy medicine, your GP may advise 5 mg of folic acid.

Folic acid on iHerb Vitamin D doses

Best supplements for women: where to start

Our overview of supplements for women over 40 and 50 shows what changes with age. Tired, with heavy periods? Get a blood test first, then read which iron supplement is best. Trying for a baby? Go to pregnancy vitamins and folic acid.

Topics in this section

Goal	What you need	Daily need (NHS)	Guide
Tiredness, heavy periods	iron after a test	14.8 mg aged 19–49; 8.7 mg from 50	iron tablets
Trying for a baby	folic acid, vitamin D	400 mcg until week 12; vitamin D 10 mcg	pregnancy vitamins
Choosing a form: folic acid or methylfolate	folic acid	400 mcg a day until week 12	folic acid tablets
Bones over 50	calcium, vitamin D, K2	calcium 700 mg	calcium and vitamin K2
Overview by age	D, B12, iron, calcium	–	supplements for women
Inositol and PCOS	limited evidence	–	inositol

EFSA sets a safe level of 40 mg a day for iron and an upper limit of 2,500 mg for calcium. The NHS advises no more than 1,500 mg of calcium a day from supplements. The chart shows how far the daily need sits from those limits:

How much you need and where the limit is: iron and calcium

Compare the daily need with the upper limit. Switch tabs

Iron Calcium

Mg a day for women

• Need aged 19–49 14.8 mg
• Need from 50 8.7 mg Drops after the menopause
• NHS: from supplements, unlikely to harm 17 mg Higher doses can cause constipation and nausea
• EFSA safe level 40 mg

Daily needs are NHS figures; upper limits are from EFSA and the NHS. Food, your multivitamin and any separate supplement all count.

Who should take care

• In pregnancy, avoid retinol supplements and fish liver oil, because too much vitamin A can harm your baby.
• After the menopause, keep vitamin A from food and supplements to 1.5 mg a day or less.
• On levothyroxine, take it 4 hours apart from calcium and iron, which reduce its absorption.
• Store iron where children can’t reach it. An overdose is dangerous for them.
• With kidney disease, take calcium and magnesium only on medical advice.

What to check before you buy

• How much iron, calcium and vitamin A your multivitamin already provides.
• Whether you take iron and calcium at the same time: calcium reduces iron absorption.
• The calcium dose per tablet: absorption is best at 500 mg or less.
• That you’ve had a ferritin test before buying iron.

How to choose on iHerb

1. Name your goal: pregnancy, low iron or bones after 50.
2. Choose one nutrient at the right dose rather than a “women’s formula” with everything in it.
3. Check the dose against the daily need and upper limit in our supplements A–Z.
4. Space out iron, calcium and thyroid medicine.

Bottom line: what to choose

Trying for a baby

Folic acid 400 mcg

Before conception and until week 12

Folic acid on iHerb

Iron deficiency confirmed by a test

Iron bisglycinate

Dose agreed with your GP

Iron on iHerb

Over 50, little dairy

Calcium with vitamin D3

No more than 500 mg calcium per dose

Calcium on iHerb

Buttons lead to selections of the right form on iHerb. These are affiliate links; your price doesn't change.

FAQ

What are the best supplements for women over 40?

Much the same as before: vitamin D in autumn and winter, iron only if your periods are heavy and a test shows you’re low, and B12 on a vegan diet. You don’t need a special “40+” formula; check it doesn’t duplicate what you already take.

What supplements do women need after 50?

After the menopause your iron need drops to 8.7 mg a day (NHS). Calcium (700 mg a day) is best from food, with a supplement only to fill the gap. Keep vitamin A from food and supplements to 1.5 mg a day or less, because more is linked to osteoporosis.

Should all women take iron?

No. Iron is for a confirmed shortfall, most often due to heavy periods or pregnancy. The NHS says 17 mg a day or less from supplements is unlikely to cause harm; higher doses can cause constipation and nausea and are dangerous for children.

When should I start taking folic acid?

Before you conceive and until 12 weeks of pregnancy, 400 mcg a day. If you’re already pregnant, start now. If you have diabetes or take epilepsy medicine, your GP may prescribe 5 mg.

Is a multivitamin for women in the UK worth it?

It can be convenient, but check the label: many contain iron and vitamin A. If you’re pregnant, choose a pregnancy-specific product without retinol. If you’re past the menopause, you may not need the iron.

Sources

1. NHS. Vitamins, supplements and nutrition in pregnancy
2. NHS. Iron
3. NHS. Calcium
4. NHS. Vitamin A
5. NIH ODS. Calcium – Fact Sheet for Health Professionals
6. NHS. Iron deficiency anaemia