NOW Foods Kelp 150mcg 200 Tabs Product Benefits Green Superfood 150 mcg of Natural Iodine Supports Thyroid Function* Vegetarian Formula Kelp is a large, leafy brown algae that belongs to the seaweed family & grows in the colder waters of the worlds oceans. It is a good source of marine minerals, including potassium, magnesium, calcium & iron. It is also an excellent source of iodine, which has been shown to support healthy thyroid function. Your thyroid gland is responsible for producing the hormones that support normal cellular metabolism. As with most green foods, kelp also contains vitamins & cell salts essential for good nutrition.*