Thyroid stimulating hormone (TSH) is produced by the pituitary gland, which is located at the base of the brain. It regulates the amount of hormones released by the thyroid. The thyroid is a small, butterfly-shaped gland located in the front of the neck that produces hormones that control metabolism and growth. TSH may be increased in cases of hypothyroidism (when the thyroid produces too few hormones), which can also be associated with low testosterone levels.
Why it's done
Your doctor may recommend checking your TSH if your testosterone level is low or if you're experiencing any of the following symptoms:
- Difficulty concentrating
- Weight gain
- Increased sensitivity to cold
There is little risk in getting a TSH test. When the needle is inserted to draw blood, some people may feel some pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise.
How to prepare
For men, there is nothing that you need to do ahead of time. You do not need to be fasting when the labs are drawn.
The normal range of TSH levels is 0.3 to 4.2 mIU/L.
A value above the normal range usually indicates that the thyroid is underactive (this is called hypothyroidism). When the thyroid isn't producing enough hormones, the pituitary gland releases more TSH to try to stimulate it.
A value below the normal range means that the thyroid is overactive, this is called hyperthyroidism. When the thyroid is producing too many hormones, the pituitary gland releases less TSH.