Quick answer

Women need 55 mcg of selenium a day, the same as men, rising to 60 mcg in pregnancy and 70 mcg while breastfeeding. Women in the United States average 94 mcg a day from food and drink. The upper limit of 400 mcg a day applies during pregnancy and breastfeeding too.^1,2

Key facts

The recommended amount stays at 55 mcg a day after age 50.²
Women take in less selenium than men, 94 mcg a day from food and drink against 132 mcg, but still well above their need.²
Men tend to have slightly higher blood selenium than women, and blood selenium falls with age.²
Europe's food safety agency applies its 255 mcg upper limit to all adults, including pregnant and breastfeeding women.³

How much women need at each stage

Selenium for girls and women, per day²
Stage	Recommended amount	US upper limit
Girls 9 to 13	40 mcg	280 mcg
Teens 14 to 18	55 mcg	400 mcg
Women 19 to 50	55 mcg	400 mcg
Women 51 and older	55 mcg	400 mcg
Pregnant	60 mcg	400 mcg
Breastfeeding	70 mcg	400 mcg

The extra 5 mcg in pregnancy and 15 mcg while breastfeeding are small next to the 94 mcg women already average from food and drink. NIH says most people in the United States get enough selenium from the foods they eat.^1,2

After 50 and 60

The recommended amount does not change with age, although blood selenium tends to decline as people get older. Women over 50 or 60 get the same advice as everyone else: count what food already supplies, since average intakes pass the recommended amount, before adding a supplement.²

Most long-term selenium trials enrolled men. In the ten randomized trials pooled in a 2018 Cochrane review, 94% of the 27,232 participants were men, so there is less direct evidence for older women.²

What selenium does in women's bodies

The roles below apply to women and men alike. What counts is the total you get from food and any supplement, measured against the recommended amount for your stage of life.¹

Contributes to normal thyroid function*^1,2

Moderate evidence

NIH describes selenium as a nutrient the thyroid gland needs to make its hormones and work properly, and selenoproteins convert the hormone T4 into its active form, T3. The thyroid holds a higher concentration of selenium than any other organ. This describes getting enough: in a 6-month trial in 368 healthy adults aged 60 to 74, taking 100, 200 or 300 mcg a day raised blood selenium but did not change thyroid function.

Amount studied: Recommended intake of 55 mcg a day for adults, from food and supplements

Contributes to normal immune function*^1,2,4

Moderate evidence

NIH lists helping the body resist germs among the jobs selenium is needed for, and the European Union's list of permitted nutrient statements, drawn up after review by the European Food Safety Authority, includes normal immune function for selenium. It describes what enough selenium does, not an effect of taking more than you need.

Amount studied: Recommended intake of 55 mcg a day for adults, from food and supplements

Getting it from food

Three ounces of cooked yellowfin tuna (92 mcg), sardines (45 mcg) or shrimp (42 mcg) covers a day's need, and so can a single Brazil nut (68 to 91 mcg). Women who eat vegetarian or vegan diets may get less. Selenium in food is mostly bound to protein, and plant foods vary with the soil they grew in.^1,2

Pregnancy, breastfeeding and thyroid conditions

The US upper limit of 400 mcg a day applies during pregnancy and breastfeeding, and Europe's lower limit of 255 mcg covers pregnant and breastfeeding women too.^1,3

Trials of selenium in pregnant women with thyroid antibodies have had mixed results. In 2017 the American Thyroid Association issued a weak recommendation, based on moderate quality evidence, against selenium supplements for pregnant women who test positive for thyroid peroxidase antibodies.²

Ask your doctor before taking a separate selenium supplement if you are pregnant or breastfeeding
Ask first if you have a thyroid condition or take thyroid medicine

Signs of too much

Hair loss and brittle or lost nails are the most common signs of getting too much selenium for a long time, and garlic breath and a metallic taste usually come first. Anyone adding selenium for hair or nails should know that too much of it causes the very problems they hope to avoid.²

Questions people ask

Is selenium safe during pregnancy?

Selenium is a normal part of the diet in pregnancy, and the recommended amount rises to 60 mcg a day. The upper limit, 400 mcg in the US and 255 mcg in Europe, still applies, and the American Thyroid Association advises against selenium supplements for pregnant women with thyroid peroxidase antibodies. Ask your doctor before adding one.^1,2,3

Is selenium safe while breastfeeding?

The recommended amount is 70 mcg a day while breastfeeding, and the 400 mcg upper limit still applies. Ask your doctor before taking a separate supplement.¹

Does selenium help with hair loss in women?

We found no trial showing that it does. Too much selenium is itself a cause of hair loss, and Europe's food safety agency based its upper limit on it.^2,3

See what we make

Every product shows its whole label and what its lab report covers. The store opens soon.

See the Full Measure line Men's Multi

Sources

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.