HDL-3 Cholesterol Unit Converter

HDL-3 is the smaller, denser subfraction of high-density lipoprotein (HDL) cholesterol. When HDL is separated by density, it divides into two main subclasses: larger, lighter HDL-2 and smaller, denser HDL-3.

Despite its smaller size, HDL-3 is protein-rich and carries higher concentrations of protective enzymes such as paraoxonase-1 (PON1), PAF-AH, and LCAT compared to HDL-2. These enzymes give HDL-3 potent antioxidant and anti-inflammatory capabilities.

HDL-3 plays an important role in reverse cholesterol transport, the process by which excess cholesterol is removed from tissues and carried back to the liver for disposal. It is typically reported as part of advanced lipoprotein subfraction testing rather than a standard lipid panel.

HDL-3 originates primarily in the liver and small intestine as nascent (pre-beta) HDL particles. As these small particles circulate and pick up cholesterol from tissues, they mature and can grow into larger HDL-2 particles through the action of the enzyme LCAT.