17β-Hydroxysteroid Dehydrogenase (17β-HSD) is an enzyme that plays a crucial role in the metabolism of steroid hormones. It is involved in the conversion of inactive steroid precursors into their active forms, such as converting testosterone from its less active form, androstenedione. This process is essential for maintaining hormonal balance in the body. There are several types of 17β-HSD, each with specific functions and tissue distributions. These enzymes are important in various physiological processes, including reproductive health, bone density, and metabolism. Dysregulation of 17β-HSD activity can lead to hormonal disorders and has been linked to conditions such as breast cancer and prostate cancer.