How much selenium you need each day.

Quick answer. The NHS says the amount of selenium you need is "75μg a day for men (19 to 64 years)" and "60μg a day for women (19 to 64 years)", and the UK Government Dietary Recommendations keep the same figures at 65 and over. Children need between 15µg and 70µg a day, depending on age and sex. For supplements, the NHS says: "Taking 350μg or less a day of selenium supplements is unlikely to cause any harm."

How much selenium per day do adults need in the UK?

The NHS page on other vitamins and minerals gives two figures:

• "75μg a day for men (19 to 64 years)"
• "60μg a day for women (19 to 64 years)"

The UK Government Dietary Recommendations, published by Public Health England in August 2016, give the same 75µg and 60µg for adults aged 65 to 74 and 75 and over. The amount does not change after 19.

What does µg mean?

µg is a microgram, a millionth of a gram and a thousandth of a milligram. Some labels write it as mcg. So 75µg of selenium is 0.075mg, by our calculation. Selenium is needed in far smaller amounts than zinc or magnesium, which is why it is the only one of the three measured in micrograms.

How much selenium do children and teenagers need?

The government tables set a figure for every age band. These are the daily amounts, in micrograms:

The figure rises fivefold from age 1 to adulthood for men and fourfold for women. Boys and girls need the same amount until 14. The document notes that its recommendations "relate to the general population", and that anyone with a medical condition looking for dietary advice should see their GP or a registered dietitian.

Why do labels use 55µg for selenium?

Because labels use a different measure. The 75µg and 60µg are government dietary recommendations. The 55µg is the nutrient reference value (NRV) for selenium, set in food labelling law so that every pack uses the same yardstick.

This is why a product can show more than 100% NRV for selenium and still provide no more than the NHS daily figure for men. 75µg is 136% of 55µg. Our guide to what NRV means shows the sum.

Can you get enough selenium from food?

For most people, yes. In the NHS's words: "If you eat meat, fish or nuts, you should be able to get all the selenium you need from your daily diet." Its listed sources are Brazil nuts, fish, meat and eggs.

The UK government's food composition data, CoFID 2021, shows how quickly the amounts add up. Per 100g, Brazil nuts carry 254µg, canned tuna in brine 69µg, grilled mackerel 60µg, baked cod 44µg and boiled eggs 27µg. Our guide to high selenium foods and Brazil nuts has the full table and per-portion figures.

How much selenium is too much?

The NHS says too much selenium can, in its mildest form, lead to loss of hair and nails. The Department of Health and Social Care advice on the same page is:

• "If you take selenium supplements, it's important not to take too much as this could be harmful."
• "Taking 350μg or less a day of selenium supplements is unlikely to cause any harm."

The 350µg line is about selenium from supplements. It is not a target. Food is counted separately, but it is worth knowing that Brazil nuts are unusually rich: CoFID's 254µg per 100g means 10g of kernels holds about 25µg, by our calculation.

How do you add up selenium from more than one product?

Selenium appears in many multivitamins, powders and combined products, so the total can be higher than any one label suggests. To check it:

• Find the selenium line on each label. It is in the nutrition table, in µg or mcg, usually with a % NRV beside it.
• Check the serving. The amount is per daily serving as the pack describes it, which may be more than one tablet or scoop.
• Add the figures together. For example, 75µg from one product and 55µg from another is 130µg.
• Compare the total with 350µg. If it is over, or you are unsure, ask a pharmacist or your GP.

Our guide to reading a supplement label covers the rest of the table.

What does selenium do?

Selenium holds these authorised health claims in Great Britain, in their set wording:

• Selenium contributes to the normal function of the immune system.
• Selenium contributes to normal thyroid function.
• Selenium contributes to the maintenance of normal hair and nails.
• Selenium contributes to the protection of cells from oxidative stress.

Where Immufix fits.

Immufix is one scoop (25g) in around 200ml of water, once a day. Each scoop provides 75µg of selenium, 136% of the NRV. By our calculation that equals the NHS figure for men, is a quarter more than the figure for women, and is just over a fifth of the NHS's 350µg line for supplements. Selenium contributes to the normal function of the immune system and to the protection of cells from oxidative stress. Every amount in the formula is on the science page.

The short version.

• The NHS says men need 75µg of selenium a day and women 60µg. The figures stay the same over 65.
• Children need 15µg to 45µg a day up to 14. From 15, boys need 70µg and girls 60µg.
• Labels use a separate yardstick, the NRV of 55µg.
• Meat, fish or nuts in the diet cover the daily amount for most people.
• The NHS says 350µg or less a day from supplements is unlikely to cause any harm. Add up every product you take.

Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle. If you have a medical condition, are pregnant, breastfeeding or taking medication, speak to your GP or pharmacist before taking any food supplement.