 Specifically designed to be as effective as possible because Survival Shield X3 includes three different types of iodine for one specific reason. To ensure bioavailability. We know that different people have different genes. Some genes are more prone to being able to absorb nascent iodine than others. We've included three different types of nascent iodine in Survival Shield X3 to ensure that your body is able to absorb and integrate at least one of them into your functioning.