Chances are, you know someone with high cholesterol. A parent, a friend, yourself. Too many fatty molecules pulsing through the bloodstream, sticking to the sides of blood vessels, and doubling—or more—the chances of a heart attack. In the United States, one in six adults has cholesterol levels considered too high and doctors write more than 200 million prescriptions a year for cholesterol-lowering drugs.

Statins, the most widely prescribed cholesterol medications, have been successful in curbing cholesterol levels for many people. But in some, statins lead to severe joint and muscle pain or liver inflammation. In others—perhaps due to genetic quirks—statins don’t lower cholesterol levels enough. And when one statin was compared with sugar pills in a clinical trial, the drug lowered the risk of heart attack by only one-third.

Although clinicians have firmly established the link between cholesterol levels and heart disease, there are still more questions than answers when it comes to the nitty-gritty molecular details of this connection. Unraveling the genetics and biochemistry of the body’s natural cholesterol-control mechanisms would do more than satisfy scientists’ curiosity: It could provide targets for better cholesterol drugs and fresh ways to predict earlier in life who is at risk for high cholesterol and related heart disease.

Illustration by Gavin Potenza