2-Methoxy-E1, also known as 2-methoxyestrone, is a naturally occurring estrogen metabolite in the human body. It is formed as a result of the metabolism of estrone, one of the primary estrogen hormones produced by the ovaries in females and, to a lesser extent, by the testes in males.

Estrogens, including 2-Methoxy-E1, have essential roles in regulating various physiological processes, including the development of secondary sexual characteristics, the menstrual cycle, and the maintenance of bone density. They also influence the growth and function of reproductive tissues.

The "2-Methoxy" in 2-Methoxy-E1 indicates the presence of a methoxy group (CH3O) on the second carbon of the estrogen molecule. Different forms of estrogen metabolites, such as 2-Methoxy-E1, can have distinct effects on the body and may be associated with different health outcomes. These metabolites can be used as markers in medical research and clinical practice to study estrogen metabolism and its potential implications for health.