Many factors contribute to hair loss. Some of them are hormonal changes, nutritional deficiency, mental and physical stress and various types medical conditions. One major cause of hair loss is problems with the thyroid. Both hypothyroidism and hyperthyroidism are responsible for contributing to hair loss in men and women. Normally, hair growth has three phases, the anagen phase, the catagen phase and the dormant phase. When a person suffers from hypothyroidism or hypothyroidism, the general mechanism of the hair growth process shuts down and loses balance. Thyroid malfunctions can force hair follicles to remain in the dormant phase for a longer period of time than normal. This leads to stalled hair growth and eventually hair loss. Read the full story on "Thyroid Hair Loss Information ". (Via Medical News Today )