Iodine supplements for underactive thyroid. We are not aware of any supplements or herbs that influence thyroid nodules. The food contains reduced levels of iodine. Hey Chad, avid follower of yours from your T-nation writings. Hypothyroidism Underactive Thyroid. Indoor cats had particularly high levels, which may be because they are constantly exposed to these compounds within their homes. If your cat appears to be in pain or distress, do not waste time on the internet, contact your vet immediately. Our volunteers have first-hand knowledge of thyroid disease, enabling them to help you, whether by phone or at meetings. Cats in the grey zone may or may not need treatment, depending upon whether symptoms are present. Thyroid disorder and sexual health Thyroid disorders are associated with a variety of sexual symptoms in men.