Cholesterol and testosterone are linked in several important ways.

Cholesterol is the biochemical starting material the body uses to make testosterone, and higher LDL cholesterol is associated with oxidative stress, inflammation, and blood-vessel changes that may affect testosterone production.

Cholesterol is often discussed as a cardiovascular risk, but it is also the raw material the body uses to make steroid hormones such as testosterone. The body produces the cholesterol it needs regardless of dietary intake, and testosterone synthesis begins when cholesterol is converted to pregnenolone in Leydig cells. Recent research indicates the relationship between circulating cholesterol and testosterone levels is complex and not fully understood. The article reviewed here summarizes known mechanisms and notes gaps where more study is needed. Key points: - Cholesterol is required for steroidogenesis: an enzyme converts cholesterol to pregnenolone, which is a precursor to testosterone. - Leydig cells obtain cholesterol both from internal synthesis and from lipoproteins in the bloodstream, including LDL and HDL. - Higher LDL cholesterol is associated with oxidative stress, chronic low-grade inflammation, and blood-vessel damage, processes that are linked with impaired Leydig cell function and may contribute to lower testosterone. - Very low cholesterol (hypolipidemia) is uncommon; in rare or severe genetic cases it could theoretically affect hormone synthesis, but evidence is limited. - Testosterone replacement therapy is reported to alter lipid measures in some men (for example, lowering HDL in certain cases) and can raise hematocrit, which is why monitoring is commonly reported during treatment. Summary: Cholesterol is the biochemical starting point for testosterone, yet the overall relationship between blood cholesterol levels and hormone production remains complex. Factors tied to high LDL—oxidative stress, inflammation, and vascular changes—are associated with possible effects on testicular hormone production, while very low cholesterol is rare and not well studied. Undetermined at this time.