Testosterone & Hyperthyroidism
Testosterone is a steroid hormone secreted from the adrenal glands, ovaries and testes 3. The hormone plays a crucial role in maintaining a healthy libido, preserving bone structure and muscle mass and maintaining energy levels. The thyroid gland plays an important role in maintaining natural testosterone levels 3. When the thyroid gland becomes overactive, this results in an increased secretion of thyroid hormone. This condition can give rise to notable weight loss, muscle loss, anxiety, mood swings and in some cases, low levels of testosterone 3.
Hyperthyroidism and SHBG Levels
Hyperthyroidism is a hereditary, treatable condition that is associated with an overactive thyroid gland 1. When the gland is overactive, the secretion of thyroid hormones into the bloodstream increases. These hormones play a crucial role in controlling weight and fat accumulation, maintaining muscle mass and steroid hormone levels. An increase in the thyroid hormones elevates testosterone levels and the blood levels of sex hormone-binding globulin, SHBG, a substance that binds to testosterone and inactivates it 3. This results in insignificant levels of testosterone in the bloodstream 3.
Symptoms of Low Testosterone and Hyperthyroidism
While the main symptom of hyperthyroidism is fatigue, rapid weight loss and an extreme quickening of the heartbeat at irregular intervals, the main symptom of low testosterone levels in men and women is a loss of desire for sex 13. The decrease in available testosterone associated with hyperthyroidism has a direct, negative impact on the libido 13. Furthermore, the body tends to respond to the high levels of SHBG by secreting additional estrogen and progesterone in both men and women. The elevated estrogen levels, in combination with the decreased amounts of available testosterone, further contributes to sexual dysfunction 3.
Treatments of Hyperthyroidism
Antithyroid drugs, such as:
- or PTU,
- or Tapazole
- can temporarily treat the symptoms of hyperthyroidism 1
However, doctors do not prescribe it as a permanent treatment plan for this condition. After a year or two, patients are weaned off the drug. In some patients, particularly women, the thyroid gland recovers during this treatment and no further treatment is necessary. In most cases, however, the only safe way to treat hyperthyroidism is to administer radioactive iodine or remove the thyroid gland surgically 1. When radioactive iodine binds to the thyroid gland, the gland is partially destroyed.
Hypothyroidism Following Hyperthyroidism
When hyperthyroidism is treated with radioactive iodine, the aim is to end the treatment before the thyroid gland is completely destroyed 1. But it is practically impossible to know exactly when the activity levels of the gland are at a normal level. So, it is common to aim at activity levels lower than normal. Patients then develop hypothyroidism, but this condition is less dangerous than hyperthyroidism 12. Hyperthyroidism can lead to a thyroid hormone rain, which can be lethal 1. It can also cause Graves' disease, an eye disease that cause the eyes to bulge out. Hypothyroidism doesn’t have immediate life-threatening consequences and can be treated permanently with thyroid hormone supplements 2. These supplements help to normalize testosterone levels 3.
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