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Selenium Side Effects

The most commonly reported side effects of selenium include fatigue, headache, and pain, based on 5,486 FDA adverse event reports from 2004 to 2025. 7.0% of reports found the drug to be ineffective.

Selenium side effects

Percentages show how often each reaction appears relative to total reports for selenium.

1
Fatigue8.7%479
2
Drug Ineffective7.0%385
3
Headache6.1%337
4
Pain5.6%305
5
Diarrhoea5.6%305
6
Nausea5.4%295
7
Arthralgia4.6%251
8
Dizziness4.5%249
9
Pruritus4.0%217
10
Off Label Use3.6%199
11
Dyspnoea3.5%193
12
Anxiety3.5%192
13
Insomnia3.3%183
14
Pain In Extremity3.3%180
15
Rash3.3%179

These are voluntary reports and do not establish that selenium caused these reactions.

Report severity

58.4%Serious3,205 reports
24.2%Hospitalizations1,327 reports
5.1%Fatal278 reports

Seriousness is determined by the reporter, not by OpenClaim.

Selenium drug interactions

Other drugs that appear in adverse event reports alongside selenium. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Sodium-oxybate4.4%243
2
Lenalidomide3.6%199
3
Adalimumab2.2%122
4
Teprotumumab-trbw1.9%103
5
Dupilumab1.6%89
6
Niacin1.3%69
7
Teduglutide1.3%69
8
Omeprazole1.1%63
9
Treprostinil1.1%62
10
Prednisone1.1%60
11
Ascorbic-acid1.1%60
12
Levothyroxine-sodium1.0%56
13
Apremilast1.0%54
14
Ibrutinib0.9%52
15
Pantoprazole-sodium0.9%51

Taken alongside

1
Ergocalciferol36.9%2,023
2
Ascorbic-acid25.9%1,421
3
Aspirin19.0%1,041
4
Calcium18.4%1,007
5
Acetaminophen17.7%972
6
Levothyroxine-sodium17.4%953
7
Zinc-sulfate-heptahydrate-cupric-sulfate-manganese-sulfate-selenious-acid16.9%927
8
Magnesium-acetate-tetrahydrate15.9%875
9
Cyanocobalamin15.1%826
10
Vitamin-e14.6%800
11
Fish13.9%761
12
Folic-acid13.5%738
13
Omeprazole11.7%640
14
Albuterol10.2%561
15
Fluticasone9.2%502

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports selenium side effects

54.8% of selenium adverse event reports involve female patients and 35.2% involve male patients. The largest age group is adult at 52%. These figures reflect who reports side effects, not underlying risk.

Sex

Female54.8%
Male35.2%
Unknown10.0%

Age group

< 20.5%
2–111.5%
12–171.4%
18–6451.7%
65+44.9%

What is selenium used for

Conditions and purposes for which patients were taking selenium when the adverse event was reported.

Abdominal DiscomfortAcneAddison^s DiseaseAdverse EventAlopeciaAlternaria InfectionAntifungal TreatmentAntioxidant TherapyArthritisArthropod BiteAstheniaAutoimmune ThyroiditisAvulsion FractureAcneAcne Conglobata

Showing 15 of 213 indications

Selenium brand names and reporting trend

Selenium is sold under the brand name Exsel.

Brand names

Exsel5,102

Quarterly reports (20042025)

20052010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking selenium with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.