Seaweed powder is a type of powdered seaweed that is commonly used in cooking, skincare, and as a nutritional supplement. It is made by drying and grinding various types of seaweed, such as kelp or nori, into a fine powder. As a nutritional supplement, seaweed powder is rich in vitamins, minerals, and antioxidants. It is particularly high in iodine, which is essential for thyroid health. It also contains other nutrients like calcium, magnesium, iron, and vitamin C.