The hormone estrogen is largely responsible for the differences between boys and girls. Children have low levels of this hormone, but during puberty, the levels increase and bodies change rapidly.

The thyroid gland is a small gland located in the front of your windpipe. It releases hormones that control your metabolism, which is your body's ability to burn calories. T3, or triiodothyronine, is one type of thyroid hormone released from the thyroid gland.

For transgendered individuals, the start of hormone therapy can be exciting and anxiety-provoking. Because a trans man's genetic gender does not match his brain gender, testosterone therapy is administered to help masculinize his body.

Porcine thyroid glandular supplements are over-the-counter nutritional supplements that are made from dried thyroid glands of pigs. People take these as a way to boost thyroid-gland function.

Cortisol is a hormone released from the adrenal gland during stress. It’s involved in immune function, glucose metabolism, insulin release and inflammation. Chronically high cortisol levels can impair your cognitive performance, decrease muscle tissue, suppress thyroid function and increase visceral fat.

Some women do not make enough progesterone, one of the dominant female hormones, to achieve and maintain a pregnancy. They may take progesterone supplements to increase progesterone levels before and during early pregnancy. Others take progesterone as part of hormone replacement therapy.

Before you reach for another cream claiming to be made from wild yams and to be a “natural” progesterone, think again. Although yams are highly nutritious, you aren’t going to adjust your hormones, prevent pregnancy or soothe menopausal symptoms from eating them.

If you’re currently taking progesterone and you develop diarrhea and heartburn, you should call your doctor and rest assured that these are common side effects of this medication. Progesterone commonly is used as part of hormone replacement therapy in women who are post-menopausal.

Testosterone is a naturally occurring hormone that is usually found in high levels in men and lower levels in women. Testosterone replacement therapy is one option to treat low testosterone levels due to aging or medical conditions.

Cortisol is a hormone produced by the body, and is intimately involved with the adrenal and pituitary systems of the body. Normal levels of cortisol, when measured at the beginning of the day, are between 6 and 23 mcg/dL, though these numbers can rise and fall throughout the day.

Estrogen dominance occurs when estrogen is in the body at a much higher level than other sex hormones, mainly progesterone. The increased level can be the result of excess estrogen production or storage, or a drop in the level of progesterone.

Several factors, including stress, medication, menopause and medical conditions like polycystic ovarian syndrome can your body's estrogen levels. While no over-the-counter supplements contain true estrogen, several medicinal herbs include compounds that mimic estrogen or act to increase estrogen levels.