what do statins do to your body

Statins lower LDL cholesterol reliably, but the net effect on your body depends on who you are, why you take them, and what else you do.

Statins work by blocking the HMG-CoA reductase enzyme in the liver, which forces liver cells to pull more LDL out of your blood. In people who have already had a heart attack or stroke, large randomized trials show this reduces the risk of another event. A meta-analysis of 26 trials with 170,000 participants found that more intensive LDL lowering cut major vascular events further [3]. In people with chronic kidney disease, pravastatin reduced cardiovascular events by about 23% and all-cause mortality by 14% over five years [25].

But statins do not just lower cholesterol. They also deplete the body of coenzyme Q10, which is made through the same biochemical pathway. This is the leading hypothesis for why statins cause muscle pain and weakness. A 2011 study found that people who developed statin myopathy had pre-existing deficiencies in mitochondrial energy production genes, and eccentric exercise made it worse [14]. A 2018 metabolomics study of rosuvastatin found evidence of mitochondrial energy impairment in the blood and urine of treated patients [15]. Statins also lower levels of the omega-3 fatty acids EPA and DHA, which are important for heart and brain health [7].

The most important distinction is between primary prevention (you have never had a cardiovascular event) and secondary prevention (you have). In primary prevention, the benefit is smaller and depends heavily on your baseline risk. A 2016 retrospective study of healthy adults who took statins for a short time found they had roughly double the odds of developing diabetes, with no clear cardiovascular benefit [21]. A Danish study of nearly 60,000 people with newly diagnosed diabetes found that high adherence to statins reduced the 5-year risk of cardiovascular events or death by about 4 percentage points, but the benefit was negligible in people under 50 [23].

The evidence for statins reducing dementia risk is observational and moderate-certainty at best. An umbrella review of 68 meta-analyses found a protective signal, but the data came mostly from observational studies with high heterogeneity, not randomized trials [19].

My call: for someone who has already had a heart attack or stroke, the evidence for a meaningful net benefit is solid. For primary prevention in a healthy person under 50, the benefit is small and the risk of new diabetes is real. The decision should be based on your individual risk profile, not a blanket recommendation. Confidence: high for secondary prevention, moderate for primary prevention in older adults, low for primary prevention in younger adults.