Thyroid Hormone Pathway

Proper levels of thyroid hormone

• Regulate body temperature
• Increase metabolism
• Improve cerebral function and prevent cognitive impairment
• Increase energy
• Increase fat breakdown, resulting in weight loss
• Regulate body temperature and body fat percentage
• Lower cholesterol
• Protect against cardiovascular disease
• Relieve symptoms of thin sparse hair, dry skin and thin nails

Proper overall body function depends on thyroid hormone. Thyroid hormone is a metabolic hormone secreted by the thyroid gland. There are two types of thyroid hormones, thyroxine (T4), and triiodothyronine (T3). The thyroid gland uses iodine to produce these hormones, thus the importance of iodine in our diet. About 80% of the thyroid hormone we produce is T4, which is the inactive hormone and held in reserve, while T3 makes up 20% of the thyroid hormone and is about four times stronger than T4. T3 is the active hormone that the body uses to function.

The release of thyroid hormones is controlled by the thyroid stimulating hormone (TSH), which is produced in the pituitary gland. When there are high levels of TSH in the blood this means the pituitary is trying to stimulate the thyroid gland to produce thyroid hormones but the gland is not responding. Because thyroid hormones are bound to proteins while circulating in our bodies, it is the unbound, available, Free T4 and Free T3 that should be measured along with TSH.

Naturally derived thyroid, with the mixture of T4 and T3, is the ideal replacement because it mimics the natural thyroid hormone produced by the body. Unfortunately, it has become routine practice to prescribe synthetic T4 alone which is not adequate and may not be converted to the more biologically active form T3, for proper levels of thyroid hormone.