selenium
Brand names: Selenium
Selenium is a mineral supplement. It provides selenium, an essential nutrient, to your body.
Drug Pricing (NADAC)
Generic Price
$0.21/unit
Generic Available
Yes (1 manufacturer)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
This medicine is a mineral supplement.
Common side effects
Tiredness, Headache, Diarrhea
Key warnings
There are no boxed warnings for this supplement.
How It Works
Selenium provides your body with selenium. Selenium is important for many bodily functions. It helps protect cells from damage and supports a healthy immune system.
How to Take It
Turn the tube upside down and twist the cap to open it. Use the clear cap to place 3 pellets under your tongue. Let the pellets dissolve 3 times a day or as needed. Take this medicine separately from food and drinks.
Pregnancy & Breastfeeding
It is not known if selenium is safe to use during pregnancy or while breastfeeding. Talk to your doctor before using this supplement if you are pregnant or breastfeeding.
Missed Dose
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.
Storage
Store this medicine at room temperature, away from heat and moisture.
Side Effects (from patient reports)
Based on 2,811 FDA adverse event reports.
FDA Adverse Event Report Analysis
Detailed analysis of 4,079 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2005–2025.
Total Reports
4,079
Death-Related Reports
236
Hospitalization Reports
1,077
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | FATIGUE | 467 |
| 2 | HEADACHE | 326 |
| 3 | DIARRHOEA | 308 |
| 4 | NAUSEA | 303 |
| 5 | PAIN | 280 |
| 6 | ARTHRALGIA | 257 |
| 7 | DIZZINESS | 250 |
| 8 | DRUG INEFFECTIVE | 234 |
| 9 | DYSPNOEA | 198 |
| 10 | INSOMNIA | 189 |
| 11 | PAIN IN EXTREMITY | 182 |
| 12 | MUSCLE SPASMS | 175 |
| 13 | OFF LABEL USE | 175 |
| 14 | ANXIETY | 174 |
| 15 | WEIGHT DECREASED | 170 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
There are no boxed warnings for this supplement.
Known Drug Interactions
7 DRUG INTERACTIONS Avoid coadministration of XOFLUZA with dairy products, calcium-fortified beverages, polyvalent cation-containing laxatives, antacids, or oral supplements (e.g., calcium, iron, magnesium, selenium, or zinc). Avoid coadministration of XOFLUZA with dairy products, calcium-fortified beverages, polyvalent cation-containing laxatives, antacids, or oral supplements (e.g., calcium, iron, magnesium, selenium, or zinc).
Mechanism: Selenium can attach to the medicine in your digestive system and stop it from getting into your bloodstream. This prevents the drug from working correctly.
What to do: Avoid taking selenium supplements at the same time as this medication. Talk to your doctor about when it is safe to take your supplements.
Common Questions
What is selenium?
How many pellets should I take?
Can I take this with food?
What should I do if I miss a dose?
How should I store this medicine?
Can I touch the pellets with my fingers?
What do I do if the medicine doesn't seem to be working?
Can I take this while pregnant?
Can I take this while breastfeeding?
What do I do if I get side effects?
What are the common side effects of selenium?
Does selenium interact with other medications?
What drug class is selenium?
Is selenium safe during pregnancy?
Related Medications in Mineral Supplement
Other drugs grouped near selenium — same-class peers and common alternatives.
ascorbic acid
Vitamin C
This medicine is a Vitamin C supplement.
Compare with selenium →
biotin
Vitamin B7
Dialyvite with Zinc is a prescription vitamin supplement.
Compare with selenium →
calcitriol
Rocaltrol
Calcitriol is a form of vitamin D that helps your body absorb and use calcium.
Compare with selenium →
calcium carbonate
Tums, Caltrate
Calcium carbonate is a medicine that can relieve heartburn and upset stomach.
Compare with selenium →
cholecalciferol
Vitamin D3
PNV-DHA is a multivitamin with minerals and essential fatty acids.
Compare with selenium →
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Pain Relievers Compared
NSAIDs vs acetaminophen — which OTC pain reliever to use
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
Related Health & Safety Data
🩺 Find a Doctor
Search prescribers for Mineral Supplement
🏨 Hospital Quality
CMS hospital ratings, safety scores & patient outcomes
💊 Supplement Data
NIH DSLD — check supplement ingredients & label claims
🍽️ Food Safety Alerts
FDA recalls, inspections & outbreak investigations
⚠️ Product Recalls
FDA, CPSC & NHTSA recall search
💉 Procedure Costs
Medicare procedure pricing for 9,297 procedures
What the FDA Data Shows for selenium
The FDA label for selenium (sold under brand names such as Selenium) classifies it as an over-the-counter product in the Mineral Supplement class. This medicine is a mineral supplement. Official labeling lists 7 commonly reported side effects, including Tiredness, Headache, Diarrhea.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 2,811 voluntary reports. The database also lists 1 documented drug interaction derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS shows a generic unit cost of $0.21.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: December 31, 2018
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages