Using data from ≈300 000 UK Biobank participants aged 40-69 y, we asked whether statins influence LDL-C, HDL-C, triglycerides and CRP differently in women and men. Multivariable models with a statin × sex interaction showed substantial sex differences in three of the four biomarkers: statins lowered LDL-C equally in women and men, but women experienced a 60 % larger drop in HDL-C, a modest 4 % rise in triglycerides (versus a 4 % fall in men), and only half the CRP reduction seen in men.