T-4 Blood Test
T-4 (Thyroxine), Free & Total T-4 (thyroxine, or tetraiodothyronine) is an hormone produced by the thyroid. It is well known that thyroid imbalances can contribute to hair loss. Both T-4 & T-3 are related to metabolism, growth, and the fight or flight response. Most of the T-4 in blood is attached to a protein - this bound T-4 does not affect the functioning of the body; less than 1% of T-4 is unattached or "free". Measuring the amount of free T-4 helps diagnose thyroid disorders which can contribute to hair loss.