The big picture: Desmosterol is an intermediate in the body’s natural cholesterol production process. Unlike dietary cholesterol, which comes from food, desmosterol is made inside the body as part of cholesterol biosynthesis. It is especially important for brain health, as the brain relies entirely on its own cholesterol production to support nerve function, cell membranes, and overall neurological health.

Role in cholesterol metabolism and brain health: Desmosterol is the final step before cholesterol is fully formed in the body. It is especially abundant in the developing brain, where cholesterol is essential for forming new neurons and supporting cognitive function. In adults, disruptions in desmosterol levels have been linked to neurodegenerative diseases, including Alzheimer’s disease. Since the brain cannot import cholesterol from the bloodstream, any issue with desmosterol metabolism can directly affect brain function.

Health implications: Elevated desmosterol levels indicate increased cholesterol synthesis, which can be a response to low cholesterol absorption or a sign of an imbalance in cholesterol metabolism. In some cases, high desmosterol may suggest that the body is trying to compensate for reduced cholesterol intake. On the other hand, low desmosterol levels can be seen with effective statin therapy, metabolic disorders, or certain genetic conditions that impair cholesterol production. Because cholesterol balance is crucial for both cardiovascular and neurological health, monitoring desmosterol can provide insight into overall lipid metabolism.

Clinical insight: Measuring desmosterol levels can help determine whether a person relies more on cholesterol synthesis or absorption. Individuals with high desmosterol may benefit more from therapies that reduce cholesterol production (such as statins), while those with low levels may need a different approach to lipid management. Additionally, given its role in brain health, desmosterol testing may offer insights into neurodegenerative disease risk, particularly in those with cognitive decline or a family history of dementia.