Thyroid disease symptoms and hypothyroidism symptoms afflict millions of adults in the USA alone. Thyroid disease symptoms are frequently misdiagnosed or undiagnosed. Approximately 10-20% of women and 1-2% of men have symptoms of thyroid problems. The most common type of thyroid dysfunction is the condition hypothyroidism, also called low thyroid or underactive thyroid.When thyroid function slows too much, one of the consequences is that metabolism in the body slows down more than it should. .