PCSK9 inhibitor

A PCSK9 inhibitor is a medicine that blocks the PCSK9 protein so the liver can clear more LDL cholesterol from the blood, producing large drops in cholesterol levels.

PCSK9 is a protein made by the liver that limits how many LDL receptors the liver keeps on its surface. Those receptors are what pull LDL cholesterol out of the blood, so more PCSK9 means fewer receptors and higher cholesterol. A PCSK9 inhibitor blocks the protein, letting the liver keep more receptors and clear more LDL, which is why these drugs lower LDL cholesterol so sharply.

The first PCSK9 inhibitors, approved from 2015, were antibody injections given every few weeks, such as alirocumab and evolocumab. They are among the strongest cholesterol-lowering treatments available, and they are used mainly for people whose cholesterol stays high despite statins or who cannot tolerate them. Newer approaches include a twice-yearly injection and, from 2026, a daily tablet. Because they rest on different biology from statins, PCSK9 inhibitors are often combined with a statin for an additional reduction in LDL cholesterol.

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