Why is iodine used as an antiseptic and disinfectant?

Iodine is widely used as an antiseptic and disinfectant because it acts as an effective bactericide and fungicide.12

These antimicrobial properties are utilized in various medical and hygiene applications, often through solutions such as Lugol’s solution—a mixture of iodine and potassium iodide—or iodine tincture, which is a solution of iodine in alcohol. Additionally, certain iodine compounds, such as iodoform, are also employed for their antiseptic qualities.12

While iodine is essential for human health in trace amounts—specifically for the production of thyroxine in the thyroid gland—it is important to note that highly concentrated iodine is poisonous and can cause serious damage to skin and tissues. Therefore, it is typically applied in diluted forms to balance its efficacy as a disinfectant with safety for topical use.231