Selenium: a deficiency that kills and a supplement that does not help

Selenium is the clearest case in nutrition of a nutrient where the two halves of the story point in opposite directions. Where the soil has none of it, people develop heart failure and giving them selenium stops it. Where people already have enough, adding more has been tested on tens of thousands of them and did nothing.

How much you need

• The RDA for selenium is 55 mcg a day for adult men and women. — adults 19+ Evidence E source
• Eight Brazil nuts from five batches held selenium amounts twenty times apart, which is why the trial refused to dose people with whole nuts. — not applicable, this is a laboratory analysis of food Evidence D source
• Americans typically get well above the recommended selenium intake, which makes deficiency the wrong frame for most readers. — United States, all ages Evidence E source

How well your body absorbs it

• Selenium bound into an amino acid was absorbed about twice as well as the mineral salt form. — adults in a low-selenium area of China with an average habitual intake of 10 micrograms a day Evidence B source
• Brazil nut butter and a selenium tablet raised blood selenium by the same amount in both vegans and meat eaters. — vegans and omnivores, adult men and women, Germany Evidence B source

What too little does

• In Chinese regions where the soil carries almost no selenium, giving people selenium cut the rate of Keshan heart disease by 86 per cent across trials covering nearly two million residents. — residents of Keshan disease endemic areas in China, 41 studies from 1935 to 2017 Evidence A source
• Selenium deficiency on its own rarely causes obvious illness, and instead produces biochemical changes that leave people vulnerable when something else goes wrong. — people with low selenium status Evidence E source
• Keshan disease, a heart muscle disease, appeared in parts of China where the soil carries almost no selenium. — residents of low-selenium regions of China Evidence E source

Who is most likely to fall short

• People on haemodialysis typically have lower selenium than everyone else, which is why it keeps being tested in them. — patients on haemodialysis Evidence C source

What the evidence does and does not show

• Across the randomised trials with a low risk of bias, selenium supplements did not change the chance of getting cancer. — adults in trials of selenium supplements against placebo, 3 low risk of bias studies Evidence A source
• The same review lists the harms found in trials: hair loss, skin inflammation, more high-grade prostate cancer in men who already had plenty of selenium, and slightly more type 2 diabetes. — participants of the Selenium and Vitamin E Cancer Prevention Trial and other randomised trials Evidence A source
• Observational studies point the other way, with a quarter less cancer in the people with the most selenium, and the reviewers explain why that does not settle anything. — participants of 70 cohort studies Evidence C source
• In people with Hashimoto's thyroiditis who are not on thyroid hormone, selenium lowered TSH and thyroid antibodies, with side effects no different from placebo. — patients with Hashimoto thyroiditis, 35 studies Evidence A source
• Across 20 cohort studies, people with more selenium in their blood died less often, which is an association rather than a result of giving anyone selenium. — general population cohorts, 17 studies for all-cause mortality Evidence C source
• In seven trials in 2,080 people on dialysis, selenium raised blood selenium and changed nothing else that was measured. — patients on haemodialysis, 7 trials Evidence A source
• Pooling five randomised trials, taking 200 micrograms of selenium a day raised the risk of type 2 diabetes by 11 per cent. — participants of 5 randomised trials and 50 non-experimental studies Evidence A source
• In observational data the same review found people with high blood selenium had three and a half times the diabetes risk of people with low levels. — participants of 50 non-experimental studies with measured selenium levels Evidence C source
• In Graves' orbitopathy, selenium cut the clinical activity score by 1.27 points at six months and made patients two and a half times more likely to report better quality of life. — patients with Graves' orbitopathy; four randomised trials out of 1,684 records screened Evidence A source
• Given to patients after heart surgery, selenium changed nothing that matters: not deaths, not days in intensive care, not hospital infections. — patients undergoing cardiac surgery; seven randomised controlled trials Evidence A source
• In rheumatoid arthritis, selenium lowered pain on a 100-point scale by about 13 points but left the inflammation markers, morning stiffness and joint swelling unchanged. — patients with rheumatoid arthritis in seven randomised trials Evidence A source
• The same trialists concluded that the recommended selenium intake rests on the wrong marker and should be revised. — selenium-deficient adults in China Evidence B source
• How much selenium survives cooking cannot be answered from the American retention tables, because selenium is not one of the nutrients they cover. — not applicable, this is a statement about the limits of a reference source Evidence E source
• Europe allows selenium to be advertised for thyroid function, immunity, hair, nails, sperm and protection of cells. — general population, EU food labelling Evidence E source
• Europe refused permission to sell selenium as good for the prostate. — general population, EU food labelling Evidence E source
• Europe also refused the claim that selenium is necessary for normal cardiovascular function. — general population, EU food labelling Evidence E source
• American food law authorises no health claim for selenium at all, so a page citing a register has to say which register it means. — United States, food and supplement labelling Evidence E source

What too much does

• The Tolerable Upper Intake Level for selenium is 400 mcg a day for adults. — adults 19+ Evidence E source
• Brazil nuts carry 68 to 91 mcg of selenium per nut and could cause selenium toxicity if eaten regularly. Evidence E source
• The usual signs of chronically high selenium intake are hair loss and brittle or lost nails, with skin rash, nausea, diarrhoea, fatigue, irritability and nervous system problems also reported. — people with chronically high intake Evidence E source
• In a trial that deliberately gave men four and eight times the safety ceiling for a year, side effects rose with the dose and no serious toxicity appeared. — 24 men with biopsy-proven prostate cancer, on 1,600 or 3,200 micrograms of selenised yeast a day for about 12 months Evidence B source
• From 200 micrograms a day upwards, selenium worsens the blood lipid profile: HDL and LDL cholesterol fall and triglycerides rise. — adults in 27 randomised trials, including healthy people, pregnant women and people with specific conditions Evidence A source
• In trials, people given selenium had 25 per cent more squamous cell skin cancer than people given placebo. — adults; 26 studies identified and 19 pooled, covering melanoma and non-melanoma skin cancers; the risk ratios below come from the experimental (supplementation) studies Evidence A source
• Brazil nuts carry natural radium, and eating them daily for a year would add more than half as much radiation as all other food combined. — not applicable, radiological measurement of a food plus a dose calculation for trial participants Evidence D source
• A single Brazil nut carries more selenium than an adult is advised to get in a day, and a cup of them carries six times the safe ceiling. — United States food supply, portion sizes as eaten Evidence E source
• Europe set its safe ceiling for selenium well below the American one, and picked hair loss as the effect that defines it. — European population, adults including pregnant and lactating women Evidence E source

What to do with this

For most people in most countries, selenium needs nothing from you. It is in fish, shellfish, meat, eggs, whole grains and dairy, and the amount in plant foods follows the soil they grew in rather than anything on the label.

The one food worth a warning is brazil nuts. One nut carries 68 to 91 micrograms, more than a day's requirement, and eating a handful daily can take you past the 400 microgram ceiling. The signs of long-term excess are specific and unpleasant: hair falling out, brittle or lost nails, a garlic smell on the breath. Treat brazil nuts as a nutrient rather than a snack.

Do not take selenium to prevent cancer. That question was tested in tens of thousands of people and the answer was no, with high-certainty evidence, and the largest trial found more high-grade prostate cancer in men who already had plenty of selenium along with slightly more type 2 diabetes.

Two groups have a real reason to raise the subject with a clinician. People with Hashimoto's thyroiditis who are not on thyroid hormone, where trials show a modest fall in TSH and thyroid antibodies. And people living in regions where the soil is genuinely depleted, which in practice means parts of China and a few other areas rather than most of Europe and North America.

If you are looking at selenium for a particular illness, the trials that exist mostly came back empty. Given after heart surgery it changed nothing measurable: not deaths, not time in intensive care, not infections picked up in hospital. In rheumatoid arthritis the pain score fell while every objective marker of inflammation stayed exactly where it was. The one exception is Graves' orbitopathy, where four small European trials found a real improvement, and that belongs in a conversation with the doctor treating your thyroid.

Brazil nuts, with the numbers

One nut is the whole day. USDA puts Brazil nuts at 1,917 micrograms of selenium per 100 g, so a 5 gram nut carries about 96 micrograms against a recommended 55. A 28 gram handful carries 537, past the American ceiling of 400 and more than twice the European one of 255. A cup carries 2,550.

Then there is the spread. Eight nuts from five batches ran from 0.25 to 5.06 micrograms of selenium per gram, twenty times apart, which is why one trial refused to dose people with whole nuts and switched to nut butter, where the variation between batches collapsed. You cannot count your intake in nuts, because no two nuts are the same nut.

That trial compared the nut butter against a selenium supplement in vegans and omnivores. Both raised serum selenium and selenoprotein P, both worked equally well, and the rise in selenoprotein P was more pronounced in the vegans, who had started lower. Food and tablet did the same job.

One oddity of Brazil nuts is worth saying plainly because it sounds worse than it is. They take natural radium up out of the soil. Fifteen grams of Brazil nut butter a day sustained for a year works out at 165 microsieverts, against roughly 300 microsieverts from everything else a person eats in a year and about 2,400 from natural background. A real addition and a small one.

Cooking, and what nobody has measured

Unsettled. How much selenium survives cooking cannot be answered from our sources. The American retention tables cover 26 nutrients across 269 methods and selenium is in none of them, alongside vitamins K, E and D, manganese and iodine. This is the difference between nobody looked and nothing happens. Selenium in food travels bound inside protein, so the chemistry suggests it leaches into cooking water rather than being destroyed by heat, and that is reasoning rather than measurement. We have no figure to give you and we are not going to invent one.

One caution about the label reading above

The line that American law authorises no selenium claim is true of the regulation we hold, which is 21 CFR 101. FDA separately permits qualified health claims about selenium and cancer risk. Those are a weaker instrument with compulsory disclaimer wording, they live outside that part of the rules, and they are outside our sources. So a selenium bottle in an American shop may carry cancer language that is perfectly lawful, and the presence of that language says less about the evidence than the word claim suggests.

Where to get it from food

The bottom line

Fifty-five micrograms a day covers an adult, and in most countries ordinary food supplies it without anyone thinking about it. The ceiling of 400 micrograms matters more than the floor, because a couple of brazil nuts a day can reach it on their own. The cancer prevention idea that sold selenium for two decades was tested properly and failed, and the trials that tested it found more high-grade prostate cancer and slightly more type 2 diabetes. The one group with a solid reason to take it is people with Hashimoto's thyroiditis who are not yet on thyroid hormone, and that is a decision for their doctor. Three more sets of trials have landed since and none of them changes the direction. After heart surgery, selenium changed nothing that matters: not deaths, not days in intensive care, not hospital infections. In rheumatoid arthritis it lowered pain by about 13 points on a 100-point scale while the inflammation markers, morning stiffness and joint swelling all stayed where they were, which argues against it touching the disease itself. In the supplementation trials pooled for skin cancer, squamous cell carcinoma was 25 per cent commoner than on placebo. The one positive result is narrow. In Graves' orbitopathy, four small trials in European patients with low selenium brought the disease activity score down and improved quality of life, while nothing measured on the eye itself changed. And the shape of the dose curve matters more than the ceiling does. From 200 micrograms a day upwards, HDL and LDL cholesterol fall and triglycerides rise, and that is half the official limit. Four more results have landed and they push on the numbers rather than on the direction. Europe re-derived its safe ceiling in 2023 and put it at 255 micrograms a day, well under the American 400, choosing hair loss as the earliest sign that defines the limit. A single Brazil nut carries about 96 micrograms, a 28 gram handful 537, and a cup 2,550, so both ceilings are a handful away. The recommendation itself is questioned by the people who tested it: selenoprotein P never reached full expression at any dose, while the marker the recommendation was built on saturated far below, and the trialists said the figure should be revised. Meanwhile the median American intake sits at 92 micrograms a day, well above it. The two regulators also disagree about labels. Europe authorises six selenium claims, covering thyroid function, immunity, hair, nails, sperm and protection of cells, and refused the ones for prostate, heart, brain and joints. The American regulation we hold authorises none at all.

Sources

1. sel-01 · Position of an expert body · expert body recommendation
   55 mcg (value from the source's table, not a sentence)
   NIH Office of Dietary Supplements, Health Professional Fact Sheet: Selenium · checked 2026-09-16 · extracted
2. se-d-03 · Mechanistic or laboratory data · laboratory compositional analysis within a randomised trial
   In the Brazil nuts, the selenium content ranged from 0.25 to 5.06 µg/g, indicating difficulties to reliably calculate the selenium amount consumed by Brazil nuts.
   European Journal of Nutrition, 2025 · checked 2026-09-21 · independently re-checked
3. se-d-13 · Position of an expert body · national dietary survey
   selenium_ug · NHANES 2021-2023, зважено · усі усі n=6694 медіана 92 p5 30 p95 218 · усі 19+ n=4886 медіана 96 p5 32 p95 227 (value from the source's table, not a sentence)
   NHANES 2021-2023, dietary recall, CDC National Center for Health Statistics · checked 2026-09-21 · independently re-checked
4. se-d-01 · Randomised controlled trial(s) · randomised supplementation trial
   Selenium as selenomethionine had nearly twice the bioavailability of selenium as selenite.
   American Journal of Clinical Nutrition, 2005 · checked 2026-09-21 · independently re-checked
5. se-d-04 · Randomised controlled trial(s) · randomised controlled trial
   Independent of the dietary pattern (vegan or omnivore), Brazil nut butter as well as supplement significantly increased serum selenium and SELENOP concentrations, while there were no changes in the placebo groups.
   European Journal of Nutrition, 2025 · checked 2026-09-21 · independently re-checked
6. sel-t1 · Meta-analysis or systematic review · systematic review and meta-analysis of community trials
   The protection rates were over 80% in 35 studies, and the overall effect (risk ratio) was 0.14 [95% CI (0.12, 0.16), P < 0.05].
   Li et al., Biological Trace Element Research, 2018 · checked 2026-09-16 · independently re-checked
7. sel-05 · Position of an expert body · expert body statement
   Selenium deficiency alone rarely causes overt illness, but it produces biochemical changes that might predispose people who experience additional stresses to develop certain illnesses.
   NIH Office of Dietary Supplements, Selenium - Health Professional Fact Sheet · checked 2026-09-16 · independently re-checked
8. sel-06 · Position of an expert body · expert body statement
   Keshan disease is an endemic cardiomyopathy that was first identified in 1935 in parts of China where the soil is low in selenium.
   NIH Office of Dietary Supplements, Selenium - Health Professional Fact Sheet · checked 2026-09-16 · independently re-checked
9. sel-t8 · Observational data · meta-analysis of randomised trials
   Selenium levels are typically lower in HD individuals.
   Wang et al., International Urology and Nephrology, 2025 · checked 2026-09-16 · independently re-checked
10. sel-t2 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis
    For analyses of RCTs with low risk of bias, the summary risk ratio (RR) for any cancer incidence was 1.01 (95% confidence interval (CI) 0.93 to 1.10; 3 studies, 19,475 participants; high-certainty evidence).
    Vinceti et al., Cochrane Database of Systematic Reviews, 2018 · checked 2026-09-16 · independently re-checked
11. sel-t3 · Meta-analysis or systematic review · Cochrane systematic review
    In the largest trial, the Selenium and Vitamin E Cancer Trial, selenium supplementation increased risks of alopecia and dermatitis, and for participants with highest background selenium status, supplementation also increased risk of high-grade prostate cancer. RCTs showed a slightly increased risk of type 2 diabetes associated with supplementation.
    Vinceti et al., Cochrane Database of Systematic Reviews, 2018 · checked 2026-09-16 · independently re-checked
12. sel-t4 · Observational data · meta-analysis of observational studies
    We found that lower cancer incidence (summary odds ratio (OR) 0.72, 95% CI 0.55 to 0.93; 7 studies, 76,239 participants) and lower cancer mortality (OR 0.76, 95% CI 0.59 to 0.97; 7 studies, 183,863 participants) were associated with the highest category of selenium exposure compared with the lowest.
    Vinceti et al., Cochrane Database of Systematic Reviews, 2018 · checked 2026-09-16 · independently re-checked
13. sel-t5 · Meta-analysis or systematic review · systematic review and meta-analysis
    Our meta-analysis found that selenium supplementation decreased TSH in patients without THRT (SMD -0.21 [confidence interval, CI -0.43 to -0.02]; 7 cohorts, 869 participants; I2 = 0%).
    Wichman et al., Thyroid, 2024 · checked 2026-09-16 · independently re-checked
14. sel-t6 · Observational data · meta-analysis of cohort studies
    An increase of selenium biomarker concentration by one SD was associated with 13 % lower all-cause mortality (RR [95 %-confidence interval], 0.87 [0.83-0.90]), 11 % lower cardiovascular mortality (0.89 [0.84-0.94]) and 15 % lower cancer mortality (0.85 [0.78-0.94]).
    Schöttker et al., Redox Biology, 2025 · checked 2026-09-16 · independently re-checked
15. sel-t7 · Meta-analysis or systematic review · meta-analysis of randomised trials
    Only selenium levels were significantly increased after selenium supplementation [SMD = 2.83, 95% CI (2.43, 3.24)].
    Wang et al., International Urology and Nephrology, 2025 · checked 2026-09-16 · independently re-checked
16. sel-t11 · Meta-analysis or systematic review · systematic review and meta-analysis
    In experimental studies, selenium supplementation increased the risk of diabetes by 11% (RR 1.11, 95% CI 1.01-1.22) compared with the placebo-allocated participants, with a higher RR in women than in men.
    Vinceti et al., European Journal of Epidemiology, 2018 · checked 2026-09-17 · independently re-checked
17. sel-t12 · Observational data · meta-analysis of observational studies
    In the nonexperimental studies, we found a direct relation between selenium exposure and risk of diabetes, with a clear and roughly linear trend in subjects with higher plasma or serum selenium levels, with RR at 140 µg/L of selenium exposure compared with a referent category of < 45 µg/L equal to 3.6 [95% confidence interval (CI) 1.4-9.4].
    Vinceti et al., European Journal of Epidemiology, 2018 · checked 2026-09-17 · independently re-checked
18. sel-r3-02 · Meta-analysis or systematic review · systematic review and meta-analysis of randomised trials
    Selenium was superior at 6 months in lowering the CAS (MD = -1.27, 95% confidence interval [CI] [-1.68, -0.85], p < .0001]), improving total GO-QOL (RR = 2.54, 95% CI [1.69-3.81], p < .00001), and improving the visual and the psychological functioning scores (MD = 10.84, 95% CI [4.94-16.73], p = .003), (MD = 12.76, 95% CI [8.51-17.00], p < .00001) respectively.
    Clinical Endocrinology, 2024 · checked 2026-09-17 · independently re-checked
19. sel-r3-04 · Meta-analysis or systematic review · meta-analysis of randomised trials
    The effect of selenium intervention on days spent in ICU (MD -0.01; 95% CI: -0.28, 0.25; P = 0.92), mortality (RR 1.07; 95% CI: 0.84, 1.37; P = 0.57) and incidence of hospital acquired infections (RR 0.98; 95% CI: 0.76, 1.26; P = 0.88) is insignificant.
    Journal of Cardiothoracic Surgery, 2024 · checked 2026-09-17 · independently re-checked
20. sel-r3-05 · Meta-analysis or systematic review · meta-analysis of randomised trials
    Seven studies including a total of 367 patients with rheumatoid arthritis were included in the study. The results showed that selenium supplementation was effective in reducing the VAS score (MD = -12.68, 95 % CI [-19.08, - 6.28], P = 0.0001) and the Ritchie index (MD = -1.13, 95 % CI [-2.22, - 0.05], P = 0.04) in patients with RA.
    Journal of Trace Elements in Medicine and Biology, 2025 · checked 2026-09-17 · independently re-checked
21. se-d-02 · Randomised controlled trial(s) · randomised supplementation trial
    This suggests that selenoprotein P is a better indicator of selenium nutritional status than is glutathione peroxidase and that the recommended dietary allowance of selenium, which was set with the use of glutathione peroxidase as the index of selenium status, should be revised.
    American Journal of Clinical Nutrition, 2005 · checked 2026-09-21 · independently re-checked
22. se-d-07 · Position of an expert body · source coverage check
    «selenium» у таблиці ретенції USDA НЕМАЄ. Release 6 рівно 26 нутрієнтів, і цього серед них немає — ні серед 16 розібраних, ні серед 10 пропущених із причиною. (value from the source's table, not a sentence)
    USDA Table of Nutrient Retention Factors, Release 6 (2007), Agricultural Research Service · checked 2026-09-21 · independently re-checked
23. se-d-08 · Position of an expert body · regulatory register entry
    POL-HC-6464 Selenium Selenium contributes to the normal thyroid function Authorised (value from the source's table, not a sentence)
    EU Register on nutrition and health claims (European Commission) · checked 2026-09-21 · independently re-checked
24. se-d-09 · Position of an expert body · regulatory register entry
    POL-HC-7917 Selenium - Selenium for a healthy prostate - Selenium is beneficial for prostate health Non-authorised (value from the source's table, not a sentence)
    EU Register on nutrition and health claims (European Commission) · checked 2026-09-21 · independently re-checked
25. se-d-10 · Position of an expert body · regulatory register entry
    POL-HC-7918 Selenium Selenium is necessary for normal cardiovascular function. Non-authorised (value from the source's table, not a sentence)
    EU Register on nutrition and health claims (European Commission) · checked 2026-09-21 · independently re-checked
26. se-d-11 · Position of an expert body · regulatory source coverage check
    (c) Validity requirement. FDA will promulgate regulations authorizing a health claim only when it determines, based on the totality of publicly available scientific evidence (including evidence from well-designed studies conducted in a manner which is consistent with generally recognized scientific procedures and principles), that there is significant scientific agreement, among experts qualified by scientific training and experience to evaluate such claims, that the claim is supported by such evidence.
    21 CFR 101, Food labeling, health claims and nutrient content claims · checked 2026-09-21 · independently re-checked
27. sel-02 · Position of an expert body · expert body recommendation
    400 mcg (value from the source's table, not a sentence)
    NIH Office of Dietary Supplements, Health Professional Fact Sheet: Selenium · checked 2026-09-16 · extracted
28. sel-03 · Position of an expert body · expert body statement
    Brazil nuts contain very high amounts of selenium (68–91 mcg per nut) and could cause selenium toxicity if consumed regularly.
    NIH Office of Dietary Supplements, Health Professional Fact Sheet: Selenium · checked 2026-09-16 · extracted
29. sel-04 · Position of an expert body · expert body statement
    The most common clinical signs of chronically high selenium intakes, or selenosis, are hair loss and nail brittleness or loss. Other signs and symptoms include skin rash, nausea, diarrhea, fatigue, irritability, and nervous system abnormalities.
    NIH Office of Dietary Supplements, Health Professional Fact Sheet: Selenium · checked 2026-09-16 · extracted
30. sel-t13 · Randomised controlled trial(s) · randomised controlled trial
    More subjects on 3200 microg/day reported symptoms of selenium toxicity; however, these reports did not correspond to peaks in plasma selenium levels. We observed no obvious selenium-related serious toxicities.
    Reid et al., Journal of Trace Elements in Medicine and Biology, 2004 · checked 2026-09-17 · independently re-checked
31. sel-r3-01 · Meta-analysis or systematic review · dose-response meta-analysis of randomised trials
    Dose-response analysis indicated that selenium administration at and above 200 µg/day decreased HDL and LDL cholesterol and increased triglyceride levels. Blood selenium concentrations at the end of the trial above approximately 150 µg/L were positively associated with triglyceride and LDL cholesterol concentrations, and inversely associated with HDL cholesterol.
    Nutrition Reviews, 2026 · checked 2026-09-17 · independently re-checked
32. sel-r3-03 · Meta-analysis or systematic review · systematic review and dose-response meta-analysis including randomised trials
    In experimental studies, we observed a higher risk for squamous cell carcinoma (risk ratio 1.25, 95 % confidence interval 1.04-1.49), but not basal cell carcinoma or NMSC overall in selenium-supplemented participants...In experimental studies, selenium supplementation was associated with higher but imprecise melanoma risk (risk ratio 1.24, 95 % confidence interval 0.57-2.68).
    Journal of Trace Elements in Medicine and Biology, 2025 · checked 2026-09-17 · independently re-checked
33. se-d-05 · Mechanistic or laboratory data · radiological analysis within a randomised trial
    However, a daily consumption of 15 g Brazil nut butter during one year would result in additional radiation exposure of 165 µSv/a.
    European Journal of Nutrition, 2025 · checked 2026-09-21 · independently re-checked
34. se-d-06 · Position of an expert body · reference dataset
    Brazil nuts — Selenium, Se 1917 UG на 100 г [fdc_id 2707492] · 1 nut 5 г 95.8 UG · Quantity not specified 28 г 536.8 UG · 1 cup 133 г 2549.6 UG (value from the source's table, not a sentence)
    USDA FNDDS 2021-2023 (Food and Nutrient Database for Dietary Studies) · checked 2026-09-21 · independently re-checked
35. se-d-12 · Position of an expert body · regulatory safety assessment
    A UL of 255 μg/day is established for adult men and women (including pregnant and lactating women).
    EFSA NDA Panel, Scientific opinion on the tolerable upper intake level for selenium, EFSA Journal 2023 · checked 2026-09-21 · independently re-checked