ApoE3, or Apolipoprotein E3, is a protein that plays a crucial role in lipid metabolism and the transport of cholesterol in the body. It is one of the three major isoforms of the Apolipoprotein E gene, with the others being ApoE2 and ApoE4. ApoE3 is considered the most common and neutral variant, contributing to the maintenance of normal cholesterol levels and supporting brain health. This protein is particularly important in the context of Alzheimer's disease, as it influences the risk of developing this condition. Unlike ApoE4, which is associated with a higher risk of Alzheimer's, ApoE3 is thought to have a protective effect, helping to clear amyloid plaques from the brain. Understanding ApoE3's function can provide insights into cardiovascular health and neurodegenerative diseases.