Dysfunction of the Endocrine System
Malfunctions of the endocrine glands can trigger the appearance of excess hair. The endocrine glands in the human body consist of the hypothalamus, pituitary, pineal, thyroid, thymus, adrenals, pancreas, and gonads which will produce hormones. These hormones are secreted inside the body, and when one malfunctions, it could cause others to malfunction, resulting in unwanted hair growth.
Irregular Menstrual Cycles
Irregular menstrual cycles can cause excess hair growth due to hormone levels.
Hyperthecosis is a condition in which the ovaries produce excess male hormones and can cause excessive hair growth, as well as cancer of the ovaries.
Specific thyroid problems could cause unwanted hair.
Fluctuations in Hormone Levels
Puberty, pregnancy, and menopause can also cause excess hair growth. During the regular systemic changes in a woman's life, hormone production varies. It is not uncommon for hormones during these times to be unbalanced. Increased male hormones called androgens can be present, which may result in unwanted hair growth.
Obesity can cause the development of a synthetic androgen hormone that causes excess hair growth.