Selenium Health Article

Preparations

Selenium is available in topical preparations and as a dietary supplement.

External preparations

Selenium sulfide for the treatment of dandruff is available as over-the-counter (OTC) scalp preparations or shampoo containing 1% or 2.5% solutions of the drug. A topical 2.5% solution of selenium sulfide is available for the treatment of tinea versicolor. Common trade names include Exsel™, Selsun™, and Selsun Blue™.

Dietary supplements

Selenium is widely available in vitamin/mineral dietary supplements and in nutritional antioxidant formulas. Although the average diet supplies enough selenium, some naturopaths recommend daily supplements of 100–200 g for adults and 30–150 g for children. Sexually active males are advised to take higher doses. Some naturopaths recommend taking selenium together with vitamin E on the grounds that their combined effect is greater than the sum of their individual effects. There are at present no definitive studies on the positive effects on health of selenium taken as a dietary supplement.

Topical preparations

Persons using selenium compounds to control dandruff or tinea versicolor should be careful to avoid applying the product to damaged or broken skin. In addition to irritating skin, selenium can enter the body through broken skin. This process is known as percutaneous absorption and can cause selenium toxicity if the preparation is used for a long period of time. Patients should wash their hands carefully after applying the selenium product to affected areas. Doing so will minimize absorption through small breaks in the skin of the hands.

Nutritional supplements

It is difficult to assess the effectiveness of dietary supplements containing selenium because there is little agreement on standards for interpreting selenium levels in human blood. Depending on their intake, healthy adults may have blood plasma levels of selenium in the range of 8–25 g/dl. In addition, most of the selenium in the body is not carried in the blood but is stored in tissue. Analysis of hair has not been useful in measuring selenium. In the absence of a useful test, people who wish to take supplemental selenium should first find out whether they live in an area that already has high levels of selenium in the drinking water and soil. Most people will probably not need more selenium than is in standard vitamin/mineral supplements. In addition, the body seems to utilize selenium more efficiently when it is taken together with vitamin E.