Indications
Selenium is a trace mineral. It is used to prevent and treat selenium deficiency, which can happen with poor diet in low-selenium areas, long-term drip feeding, kidney dialysis and some bowel diseases. It is often included in multivitamin and antioxidant products, and doctors may use it in certain thyroid eye conditions.
How It Works
Selenium is part of enzymes that protect cells from damage (antioxidant enzymes) and enzymes that activate thyroid hormone. It also supports the immune system.
Dosage and Administration
- Adults: normal daily need is about 55 to 70 mcg. Supplements usually provide 50 to 200 mcg a day.
- Do not take more than 400 mcg a day from all sources (food and supplements) unless a doctor advises.
- Deficiency, drip feeding and children: as prescribed. Injections are given by a doctor or nurse.
Take by mouth with food.
Interactions
No major interactions are common at normal doses. High doses may slightly increase bleeding risk with blood thinners such as Warfarin. Vitamin C taken at exactly the same time may reduce absorption of some forms; it is reasonable to take them a little apart. Tell your doctor about all medicines and supplements you take.
Contraindications
Allergy to selenium or any ingredient of the product. Avoid supplements if you already have high selenium levels.
Side Effects
At normal doses side effects are uncommon; some people have mild stomach upset. Long-term high intake can cause selenium toxicity (selenosis): garlic smell on the breath, metallic taste, hair loss, brittle or discoloured nails, skin rash, tiredness, irritability and nerve problems.
Get urgent medical help if you notice severe vomiting or diarrhoea, trembling, confusion, difficulty breathing or chest pain after taking selenium, or signs of a severe allergic reaction.
Pregnancy and Lactation
Safe at normal recommended amounts (around 60 to 75 mcg a day) during pregnancy and breastfeeding. Avoid high-dose supplements unless a doctor advises them.
Precautions and Warnings
Check the selenium content of all your supplements to avoid taking too much. Selenium has a narrow gap between a helpful and a harmful dose. Some studies have linked high-dose selenium to a higher risk of type 2 diabetes, so long-term high doses are not advised. Take extra care with kidney disease.
Overdose
A large overdose can cause vomiting, diarrhoea, garlic breath, shaking, low blood pressure and, rarely, heart and breathing problems. Get urgent medical help.
Therapeutic Class
Mineral supplement (trace element).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.