The Facts About Statins and Dementia Risk

Here’s what you need to know: the claim that low blood cholesterol—and therefore statin use—causes dementia is not at all supported by a large body of scientific and clinical evidence. In fact, extensive research shows the opposite is true: that statins are a safe tool for helping prevent cardiovascular disease—which is the leading cause of death in the United States and most parts of the world—and that lower cholesterol levels, and indeed statin use, do not cause dementia and may in fact be associated with reduced dementia risk, not the other way around.

What the research shows

The evidence for statins preventing heart attacks, strokes, and cardiovascular death is overwhelming and comes from decades of rigorous research involving hundreds of thousands of patients. What’s more, there is ample evidence that these drugs are at worse neutral, and at best beneficial, for brain health. If your doctor has prescribed a statin, it’s because you’re at risk for cardiovascular disease—the leading cause of death in the United States.

“At least 30 studies have examined the relationship between lipid-lowering medications and dementia risk or cognitive side effects,” says Dr. Alon Gitig, Director of Preventive Cardiology at the Atria Health Institute. “Randomized trials and the most high-quality syntheses have not shown increased risk of dementia or a consistent signal of worsening on neurocognitive testing..”

Most of these studies followed participants for two to five years, with some extending up to 25 years. Across multiple systematic reviews and meta-analyses, the findings are strikingly consistent: there is no difference in cognitive outcomes—including memory, executive function, or overall cognition—between statin users and non-users. This holds true even among older adults and those taking high doses of statins.

“From a neurological standpoint, current data do not support statins as a cause of cognitive decline,” says David Dodick, a top neurologist and the Chief Science and Medical Officer of the Atrial Health Institute. “In older adults, studies show neutral cognitive effects overall, and some observational research links statin use to lower dementia risk, likely through vascular-risk reduction and favorable effects on the cerebral endothelium—the lining of blood vessels around and in the brain. Rare, reversible cognitive side effects can occur, so evaluate symptoms individually.”

Recently, the largest systematic review and meta-analysis conducted to date evaluated 55 observational studies encompassing a total of 7,786,651 patients. This study demonstrated that statin use was associated with a reduced risk of all dementia, and the two most common forms of dementia: Alzheimer’s disease and vascular dementia. In addition, longer duration of use was associated with greater protective effects, and rosuvastatin showed the greatest reduction in dementia risk.

Several trials included serial neurocognitive testing over periods ranging from 19 months to six years, and none found meaningful differences between the treatment and placebo-treated groups. One study focusing specifically on patients aged 70 to 90 likewise found no evidence of cognitive harm. Even among individuals achieving very low LDL cholesterol levels, researchers saw no adverse effects on brain function.

Reflecting this extensive evidence, The United States Preventive Services Task Force and the American Heart Association both strongly recommend statin therapy for appropriate patients based on the evidence. Similarly, the American Stroke Association and the American Diabetes Association all state that fears of statin-induced cognitive dysfunction are unsupported—and should not discourage appropriate statin therapy.

Why the confusion persists

So where did the idea that statins harm cognitive health come from? There have been case reports over the years of people experiencing memory changes shortly after starting a statin, and complaints of brain fog or memory issues do pop up in clinical practice in some people taking the medications. The U.S. Food and Drug Administration even issued a warning in 2012 about memory effects as a potential risk of statin drugs based on case reports and reports of side effects after the drugs were on the market.

But here’s the critical context: when these side effects do occur, they resolve quickly when the medication is paused or the dose is reduced in nearly all cases. And more importantly, these isolated reports have not been substantiated by controlled studies.

The concern also stems from a logical but incomplete understanding of how cholesterol works in the body. The brain uses a lot of cholesterol to support healthy neuron functioning, so when statins lower cholesterol levels in the blood, it seems reasonable to worry they might deprive the brain of this essential substance.

However, as Dr. Gitig explains, “the brain’s cholesterol pool is very much separated from the blood pool.” The blood-brain barrier prevents most cholesterol from crossing from the bloodstream into the brain. While some mechanisms allow for passage, they typically occur at very low levels. “While research is still emerging, the scientific consensus is that the brain likely receives the vast majority of its cholesterol requirements from synthesis by cells in the brain itself,” Dr. Gitig says. “Therefore, the cholesterol content in the brain’s cells would be minimally affected by the level of cholesterol in the blood under normal physiologic conditions.”

Additionally, cholesterol made by brain cells stays around for months to several years, so any changes in brain cholesterol levels caused by a medication someone takes today should have minimal impact on the brain’s total cholesterol supply.

More reassuring cholesterol evidence

To underscore the idea that low cholesterol does not lead to dementia, Dr. Gitig and other experts point to Mendelian randomization studies—see here, here, here. and here—which look at people born with genetic variants that lead to lower-than-average cholesterol throughout their entire lives. These studies generally do not suggest a link between lower cholesterol and dementia risk. Some subjects in those studies had very low LDL cholesterol levels (30 to 50 mg/dL) similar to what’s achieved with aggressive medication management.

Another time when people generally have low cholesterol is immediately after birth. New infants typically have LDL cholesterol around 50 to 70 mg/dL or even lower, which is a range commonly achieved with use of medications. Brains are rapidly developing during this time, and newborn infants make great strides in brain cell function at these low blood cholesterol levels.

In fact, high LDL cholesterol is actually a risk factor for dementia. The supply of blood to the brain by way of small blood vessels (microvascular), and the integrity of the blood brain barrier, plays a significant role in preserving cognitive health and when compromised, plays a role in the development of dementia, including Alzheimer's disease. The brain’s blood vessels are generally healthier and better at supplying blood and nutrients to brain tissue in those with low cholesterol levels maintained over many years.

Dr. Gitig notes that statins have a number of direct beneficial effects on artery health—including microvascular vessel health—aside from cholesterol lowering, which could promote good brain health by optimizing blood supply, blood brain barrier integrity, and nutrient delivery.

Why taking statins as prescribed matters

Overall, statins are very safe, but like any medicine, they can cause side effects. Statins very slightly raise the chance of new diabetes, mostly in people already at risk. That’s about 2 extra cases per 1,000 people each year. Many people get mild muscle aches for lots of reasons, and most reports show they are not often caused by the statin itself. In careful studies, statins account for only about 1–2 extra people with muscle pain out of 100 compared with placebo. While elevations in liver enzymes can happen, these usually resolve and true liver damage is extremely rare. The good news is that if side effects occur, they almost always improve when the dose is lowered, the statin is switched, or the medicine is stopped.

If you experience side effects from your statin, talk with your doctor. There are multiple statin options at different doses, as well as alternative medications that can lower cholesterol. Your care team can work with you to find an approach that manages your cardiovascular risk while minimizing side effects.

What about those few cases of memory problems?

While the overwhelming evidence shows statins don’t cause cognitive problems, there have been rare reports of individuals experiencing memory changes. This is presumably related to statins crossing the blood-brain barrier and entering brain cells, inhibiting cholesterol synthesis there. “It may be that some people's baseline level of brain cell cholesterol synthesis is lower than normal and they are more sensitive to feeling an effect,” says Dr. Gitig.

Most statins can easily move through fatty layers in the body, including the protective barrier around the brain, because they dissolve well in fat. Some statins, like rosuvastatin and pravastatin, don’t cross this barrier as easily. However, studies in mice have found that pravastatin can still get into the brain using special transport systems. It’s not yet clear how much of this happens in people, or whether the same is true for rosuvastatin.

At some health care practices, including the Atria Health Institute, physicians frequently check a biomarker called desmosterol. Desmosterol is produced in brain cells at one step in the multi-step process of cholesterol formation, so it goes down when statins inhibit cholesterol synthesis, Dr. Gitig explains. “Small studies suggest that blood levels of desmosterol can provide a window into brain levels,” he says.

Studies have found that average desmosterol levels tend to be significantly lower in people with dementia than in controls, although researchers aren’t certain if this reduction is causal. In addition, there is considerable overlap between the range of values seen in people with normal cognition versus those with dementia. “While we don’t yet know that we can use desmosterol levels as a firm indicator of dementia risk, this biomarker provides one clue we can use to piece together whether a statin might be causing memory issues or whether extremely low levels might not be advisable in someone with significant risk factors for dementia,” says Dr. Gitig.

In such cases, doctors might consider adjusting the statin dosage or using a different medication class, although this decision needs to be weighed against the much more firmly established cardiovascular benefits of the drug, especially in people at high risk for atherosclerotic disease. Current research suggests that other cholesterol medication classes—ezetimibe, PCSK9 inhibitors, inclisiran, and bempedoic acid—do not cross the blood-brain barrier to a meaningful degree.

The bottom line

The claim that statins cause dementia is contradicted by decades of rigorous research. While there can be some side effects associated with statins, the cardiovascular benefits of statins far outweigh these small risks, and there’s no credible evidence linking these medications to increased dementia risk.

If you're taking a statin and concerned about your memory or other side effects, talk with your doctor. Short-term memory loss after starting statins are rare and reversible, and are frequently confounded by the large number of other potential factors that can cause brain fog. Your care team can work with you to determine the cause and adjust your treatment if needed.

For most people, statins remain a powerful tool for preventing heart disease and stroke—and the evidence clearly shows they do so without harming your brain.