Function – Selenium contributes to:

The normal function of the immune system - Selenium appears to play a role in cell-mediated immunity.

Normal spermatogenesis – There is a protein selenium-dependant in sperm (selenoprotein) that has a structural and an enzymatic role. It is responsible for both the maintenance of motility and the structural integrity of the tail of the sperm. Both human and other mammals exhibit reduced sperm motility and increased sperm rupture under conditions of low selenium supply.

The maintenance of normal hair and normal nails - Deficiency in selenium has been shown to result in various disorders including impairment of hair. Clinical manifestations such as white nail beds, pseudoalbinism, alopecia and thin hair have been observed in particular in patients receiving total parenteral nutrition lacking selenium. Administration of selenium was able to restore these deficiency symptoms.

The normal thyroid function - The known biological functions of selenium include regulation of thyroid hormone action.