Kelp is a seaweed and is a good source of marine minerals including potassium, magnesium, calcium and iron. It is also an excellent source of iodine. Kelp also contains vitamins and cell salts essential for good nutrition. As a dietary supplement, take 1/4 level teaspoon 1 to 3 times daily, preferably with meals.
Kelp is also the world’s most complete and natural skin care ingredient containing an extraordinary array of minerals, vitamins, and rejuvenating factors your skin needs. It is also used by spa professionals and beauty therapists in facial masks, soap, shampoos, lotions, creams, cleansers, seaweed body wraps, and body salt rubs.
Please note if you are on other medication for thyroid problems you should consult your doctor before consuming kelp.
See what Wikipedia says:
http://en.wikipedia.org/wiki/Kelp