The seven key hormones in the body are cortisol, epinephrine, thyroid, testosterone, estrogen, insulin, and growth hormone. These hormones regulate many bodily functions such as metabolism, growth, reproduction, and mood. Cortisol helps the body respond to stress. Epinephrine is involved in the fight-or-flight response. Thyroid hormone helps control metabolism. Testosterone is a male hormone and estrogen is a female hormone; both are involved in the reproductive process. Insulin helps regulate blood sugar levels. Growth hormone helps to regulate cell growth and development. Each of these hormones plays an important role in the body.