Androgen biosynthesis is a complex biochemical process that results in the production of androgens, the male sex hormones, with testosterone being the most well-known. This process involves a series of enzymatic reactions that convert cholesterol into androgens. It occurs in several tissues, most notably in the Leydig cells of the testes in males, the theca cells of the ovaries in females, and the adrenal cortex in both sexes. The biosynthesis pathway starts with the transport of cholesterol into the mitochondria, where it undergoes a series of transformations. The initial step is the conversion of cholesterol to pregnenolone, catalyzed by the enzyme cytochrome P450scc (side-chain cleavage enzyme). Pregnenolone then serves as a precursor for the production of all steroid hormones, including androgens. Subsequent steps involve the conversion of pregnenolone to DHEA (dehydroepiandrosterone) and androstenedione, which can be further converted to testosterone and other androgens. The regulation of androgen biosynthesis is tightly controlled by the hypothalamic-pituitary-gonadal (HPG) axis through the secretion of hormones such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Disruptions in this biosynthetic pathway can lead to various disorders, including androgen deficiency, polycystic ovary syndrome (PCOS), and congenital adrenal hyperplasia (CAH). Understanding androgen biosynthesis is crucial for diagnosing and treating conditions related to androgen imbalance.