Selenomethionine is an organic form of the mineral selenium, which is essential for human health. It is an amino acid that contains selenium in place of sulfur, making it a key component in various biological processes. Selenomethionine is found in certain foods, such as Brazil nuts, fish, and grains, and is often used as a dietary supplement to support immune function and antioxidant activity. This compound plays a crucial role in the synthesis of selenoproteins, which are important for protecting cells from oxidative stress and maintaining thyroid function. Adequate selenium intake, including selenomethionine, is vital for overall health, as both deficiency and excess can lead to health issues.