Blood thyroid tests measure circulating hormones. It is generally felt that if these levels are normal, then one's thyroid function is normal. It is also possible that blood thyroid profiles are not always accurate. The problem is that the hormones must pass into the cells and be converted and utilized there. Hormone receptors must be present to allow the hormones to act. The hair analysis assesses the cellular effectiveness of hormones. Often the result is different. Both tests have value. The hair analysis test may give a clearer picture of actual glandular activity.
The higher the level of hair calcium, in general, the lower the effective activity of the thyroid gland. This occurs because one of the effects of T3 and T4 is to lower calcium levels in the tissues and at times, in the blood. For example, it is known that hyperthyroidism can cause tetany or muscle contractions that are due to low serum calcium.
Lower calcium is also associated with increased cell permeability. This may allow more thyroid hormone to enter the cells, increasing the cellular effect of the same amount of circulating serum thyroid hormones.
A lower hair potassium is associated with reduced cellular effects of thyroid hormones. It is known that low potassium is associated with reduced sensitivity of the mitochondrial receptors to thyroid hormone. Also, low potassium and sodium are associated with reduced cell permeability to thyroid hormones. Essentially, potassium sensitizes the cells to thyroid hormone.
This means that even if the serum thyroid hormone levels are normal, when tissue potassium is low they may not be utilized, resulting in a low thyroid effect. This commonly contributes to thyroid problems in slow oxidizers.