No, thyroxin is not used to treat obesity. Thyroxin is used to treat people whose thyroid doesn’t produce enough which can be assessed by measuring the amount in the blood. Thyroxin is prescribed and usually taken for the remainder of life.
The body to regulate the basal metabolic rate uses thyroxin. (The number of calories burned when a person is at rest sitting or laying down.) If the body produces insufficient thyroxin, weight gain and fatigue are common. If excess thyroxin is produced the person’s eyes will bulge out and weight loss is common.
If a person has insufficient iodine in their diet, they will develop a goiter, which is an enlargement of the thyroid at the base of the throat. If thyroxin is deficient during pregnancy, the infant is born with mental and physical retardation (cretinism). Iodine is an integral component of thyroxin. Iodized salt is a one-food way to get iodine into the diets of people who do not eat seafood on a regular basis.