Hashimoto's thyroiditis is a common problem though more common in females than males. It is a auto-immune disease in which the immune system develops an error and attacks it's own tissue, destroying it. This may result in a goiter as the failure of the gland stimulates the pituitary gland in the brain to stimulate the failing thyroid gland causing it to enlarge. Ultimately the gland fails completely in spite of overstimulation of the pituitary gland & symptoms of low thyroid activity results. The treatment is relatively simple: Oral thyroid pills in a proper dose as determined by a physician with proper lab. tests of the blood thyroid level as well as the level of pituitary stimulating hormone. Adjust the dose of thyroid medication until the levels of both hormones are in the normal range & monitor frequently to be sure the need to change the thyroid dose hasn't changed (or adjust the dose if it has). Thyroid hormone, known as thyroxine, comes in a small pill and comes in a large variety of doses (many people of different sizes and ages including infants may need thyroid) & each dose has a different color. The color coding is the same even if the thyroid is made by different companies. Generic thyroxine is ok & is cheap. Treatment can make a big difference in things like energy level, etc but more important, low thyroid can result in heart damage & congestive heart failure. So keep the thyroid in proper control with a pill a day-but be sure it is the right pill.