Hormonal changes refer to fluctuations in the levels of hormones within an organism. Hormones are chemical messengers produced by glands in the endocrine system, which regulate various bodily functions such as growth, metabolism, and reproduction. The phrase "hormonal changes" typically refers to shifts or alterations in these levels that can be caused by a variety of factors including stress, diet, exercise, illness, or other environmental influences. These hormonal fluctuations can result in physical symptoms such as mood swings, weight gain or loss, changes in libido, and other physiological responses.