Selenium: How Much Is Enough?
Checking the back of a hair, skin and nail formula, you may find selenium listed in micrograms beside zinc and biotin. This guide explains what selenium is, the common forms, the 55 µg NRV, why EFSA's 255 µg limit leaves a narrow margin, and how to add up every source.
What selenium is
Selenium is an essential trace mineral, needed in tiny amounts measured in micrograms (µg), where 1 µg is a thousandth of a milligram. In the body it becomes part of a group of proteins called selenoproteins, including enzymes found in the thyroid gland and in cells throughout the body.
The EU authorises several selenium claims, among them the normal function of the immune system, normal thyroid function, the maintenance of normal hair and nails, and the protection of cells from oxidative stress. The exact wording is in the authorised claims box below. Selenium is a nutrient where the gap between enough and too much is small, so the amount matters as much as the form.
Forms you'll see on labels
| Form | What to know |
|---|---|
| L-selenomethionine | The main organic form found in foods such as grains and nuts. Common in single-ingredient tablets. |
| Selenium-enriched yeast | Yeast grown in a selenium-rich medium; most of its selenium is selenomethionine. |
| Sodium selenite | An inorganic form widely used in multivitamins and hair, skin and nail blends. |
| Sodium selenate | Another inorganic form, used in some multivitamins and drinks. |
| Brazil nut extract or powder | Natural selenium source, but the content can vary widely from batch to batch. |
All of these forms count towards the same daily total. You can find selenium alone and in combinations in our minerals collection.
How much selenium?
- NRV (EU label reference): 55 µg a day. A product with at least 8.25 µg per daily portion (15% of NRV) may use the authorised claims.
- Upper limit: 255 µg a day from all sources for adults, as set by EFSA in 2023 (lowered from the previous 300 µg). Children have lower limits scaled to body weight.
- Typical supplements: 50 to 200 µg per serving. Hair and beauty formulas often carry 55 to 165 µg.
- Other guidance: the NHS gives 75 µg a day for men and 60 µg a day for women as daily needs.
Food sources include Brazil nuts, fish and seafood such as tuna, sardines and prawns, eggs, meat, poultry, dairy and grains. The selenium content of plant foods depends on the soil where they grow. Brazil nuts are unusually rich: according to the NIH, an ounce (about 6 to 8 nuts) can provide around 544 µg, though values vary widely. Eating several Brazil nuts every day on top of a supplement can quickly go past the upper limit.
Long-term intakes that are too high can cause selenosis. Early signs include a garlic smell on the breath and a metallic taste; more common signs are hair loss and brittle nails.
Who should check with a doctor or pharmacist first
- People with a thyroid condition or taking thyroid medicines should ask their doctor before adding selenium.
- People receiving cancer care, for example with the chemotherapy medicine cisplatin, should discuss any supplement with their oncology team.
- Anyone taking more than one product: multivitamins, hair formulas, men's and fertility blends often all contain selenium.
- Pregnancy and breastfeeding: needs rise only slightly; use products made for this stage and check with your doctor or midwife.
- Children: their upper limits are much lower than adults'. Check the age on the pack and ask a doctor or pharmacist.
How to read a selenium label
- Check the unit: selenium is listed in µg (sometimes written mcg). 200 µg is 0.2 mg.
- Per serving vs per tablet: two gummies may make one serving; double the per-gummy figure if so.
- %NRV: 55 µg is 100% NRV, 110 µg is 200% and 165 µg is 300%.
- Do the total: add selenium from every product you take, plus regular Brazil nuts, and compare it with 255 µg.
- Servings per pack tell you how long the product lasts at the stated dose.
Bahrain & GCC notes
Fish and seafood are part of many Gulf diets and already supply selenium, so a high-strength selenium tablet is often unnecessary on top of a multivitamin. Brazil nuts are a popular snack in mixed nut packs; enjoy them, but count them. Store tablets in a cool, dry place away from summer heat. See single and combined options in the minerals range.
Reading a real label
Vitabiotics Perfectil Hair, 60 Tablets| On the label | What it means |
|---|---|
| 165 µg selenium per 2 tablets | 300% NRV, against the 55 µg reference intake |
| EFSA upper limit 255 µg a day | From all sources: count your multivitamin and diet too |
| Also 15 mg zinc, 150 µg biotin | Check for overlap with other hair or skin products |
| Serving = 2 tablets | 60 tablets is a 30-day supply |
- Selenium contributes to the normal function of the immune system
- Selenium contributes to normal thyroid function
- Selenium contributes to the maintenance of normal hair
- Selenium contributes to the maintenance of normal nails
- Selenium contributes to the protection of cells from oxidative stress
Applies to products that provide at least 15% of the NRV per daily portion (a 'source of' the nutrient).
Products with Selenium
Always read the label and check the amount per serving.
Known NutritionKnown Nutrition Hair, Skin and Nails, 60 GummiesBHD16.500
VITABIOTICSVitabiotics Perfectil Hair, 60 TabletsOut of stock
RITERITE Hair Gummies, 60 GummiesBHD20.570
VITABIOTICSVitabiotics Pregnacare Conception, 30 TabletsBHD13.200
APEXAMAPEXAM Fertisitol, 90 CapsulesBHD27.390Frequently asked questions
How much selenium is too much?
EFSA set the adult upper limit at 255 µg a day from all sources in 2023. Long-term intakes above this can cause selenosis, with signs such as hair loss and brittle nails.
Can I get selenium from Brazil nuts instead?
Brazil nuts are very rich in selenium, but the amount varies widely. One or two nuts can already approach or pass the NRV, so count them if you also take a supplement.
Is selenomethionine or selenite better?
Both count towards your daily selenium. Selenomethionine is the main form in foods; selenite is common in multivitamins. The amount per serving matters more than the form.
Why is selenium shown in µg, not mg?
The body needs selenium in very small amounts, so labels use micrograms. 1,000 µg equals 1 mg.
Should I take selenium for my thyroid?
If you have a thyroid condition, ask your doctor before taking selenium. The EU-authorised claim refers to normal thyroid function, not to any medical condition.
