HDL vs. LDL
HDL is known as "good cholesterol" because it transports cholesterol to your liver to be expelled from your body. HDL helps rid your body of excess cholesterol so it's less likely to end up in your arteries.
LDL is called "bad cholesterol" because it takes cholesterol to your arteries, where it may collect in artery. Too much cholesterol in your arteries may lead to a buildup of plaque known as atherosclerosis. This can increase the risk of blood clots in your arteries. If a blood clot breaks away and blocks an artery in your heart or brain, you may have a stroke or heart attack.