Alirocumab works by inhibiting the PCSK9 protein. PCSK9 binds to the low-density lipoprotein receptor (LDLR) (which takes cholesterol out of circulation), and that binding leads to the receptor being degraded, and less LDL cholesterol being removed from circulation. Inhibiting PCSK9 prevents the receptor from being degraded, and promotes removal of LDL cholesterol from circulation.[5]