Thyroid levels between 0.3 and 3.0 are considered ideal by the American Association of Clinical Endocrinologists. However, these levels have only recently been established, and there is still much debate in the medical community over the change, states Everyday Health. Previously, levels ranging between 0.5 and 5.0 were considered normal.
The controversy regarding the optimal range for thyroid-stimulating hormone has left the medical community divided. Some practitioners have adopted the new standards, while others continue to go by the old standards. Endocrinologists worry that this division is causing some women to go undiagnosed and untreated when they actually have a thyroid disorder, while opponents fear that using the narrower normal range may lead to misdiagnoses and unnecessary treatments, says Everyday Health.