In a new analysis of thirty years worth of data, experts say that many of the side effects listed on the packaging of statins are not as common as once thought.
Earlier this year in the Lancet, members of the Cholesterol Treatment Trialists’ (CTT) Collaboration reported that the odds of statin-related adverse events are overstated. In fact, of the 66 possible side effects included in packaging inserts, only four of them turned out to be associated with the drug. What’s more, the likelihood of those adverse events happening was much smaller than doctors had realized.
Re-evaluating Adverse Events and Side Effects Linked to Statins
In an update to an ongoing project to evaluate statin side effects, the researchers gathered data from 19 research studies published between 1994 and 2023 to see how common adverse events or side effects from the cholesterol-busting drug really are. They crunched the numbers comparing data from more than 123,000 participants over several years in search of patterns in the adverse event reports that indicate statins are causing them. It turns out that, with the exception of myopathy, type 2 diabetes, abnormal liver function and changes in urinary composition and oedema, adverse events from statins are vanishingly rare.
The CTT researchers have already shown that statins increase the occurrence of myopathy and type 2 diabetes, but they discovered that the severity and frequency of the two were lower than they had expected.
It transpired that muscle pain and or weakness (myopathy) is actually a rare side effect. The researchers report that statins only raise a person’s chances of having mild muscle pain by 7% in the first year. The team found that 90% of myopathy cases disclosed by people in clinical trials for statins were not caused by the drug.
They also spotted that the statins increased HbA1c measurements in participants by a very small amount – 0·06% for folk on moderate or low intensity statins. It’s also worth noting that that the underlying health issues that might prompt a prescription for statins also contribute to type two diabetes. Would it be such a big surprise if somebody got a diagnosis for it soon after picking up their statin script?
Transparency Is Important For Reporting Adverse Events
One of the complicating factors of inventing new treatments for diseases is adverse event reporting. When researchers run a clinical trial, they have to record anything and everything that happens to participants while they are taking part and sometimes for a period of time after. Some of these adverse events will be because of the medicine or procedure, and some will be unrelated. This is why when you look at the vaccine adverse event reporting databases, you will spot illnesses and deaths that have noting to do with the vaccine at all.
The researchers are ethically bound to report every adverse event they notice, even if it seems far-fetched, just in case it later proves to be connected. Over time, we review adverse events and side effects reports and see if any patterns emerge. This is important and useful information.
Medical regulatory bodies ask, quite reasonably, that drug companies are open and honest about potential side effects. As a result, sometimes we and up with package inserts or information sheets with long lists of possible side effects that are very, very rare, or might not be linked to the medicine after all. According to some research, 2% of people stop taking their statins because of muscle pain. It’s worth noting that if you’ve been told that it’s a common side effect, you are more likely to notice it. How many patients stop taking their statins because they misattributed aches and pains due to age or old injuries to their medicine?
Reviewing the Evidence for Statin Side Effects
Every so often, clinicians like to go back and check whether the listed side effects or adverse events that were reported are genuinely caused by the treatment and to check whether any new ones need to be added. In this case, heart specialists recognized that the side effects listed on statin packages might put folk off taking them, so it’s time to assess if they need updating.
The most common adverse events that people have linked to statins are liver function problems, depression, impaired cognitive function, kidney problems, lung disease, pancreatitis, sleep disturbances, unusual urine test results, swelling, myopathy and type 2 diabetes. The researchers thoroughly evaluated thirty years worth of data to figure out which of these adverse events were worth worrying about and which were statistical blips.
So how would they go about it? Basically, they did a huge review of existing studies to see which adverse events came up consistently and what the chances of those adverse events happening to patients are. If you want to do a useful analysis, you need big numbers so that rare events don’t skew the results. You need long follow-up periods so that you don’t miss any reports. Most importantly, you want studies that researchers carefully designed to eliminate confounding factors that might exaggerate or underestimate the frequency of side effects.
Crunching the Numbers
In short the team performed a finger tip search of the research literature to find every double blinded randomized placebo controlled clinical trial involving statins. Next they combed through the methods of each paper to make sure they only included data that met a predetermined set of quality checks. Only papers published in peer-reviewed journals with clearly described methods and individual participant data made the grade. Then they went a step further. They chucked out studies with fewer than 1000 participants, under two years of follow-up, and those that didn’t make sure that nobody knew whether participants got a placebo pill or statins until after they analysed the data.
In the end they found 19 clinical trials that fit the bill. From those 19 studies, the team compiled all the adverse event data, regardless of the likelihood statins were the cause, and all the participant data. Then they pooled and reanalysed all of the data to see which associations were real and which were probably coincidences or over reported.
They followed an ‘intention to treat’ philosophy – including every participant who dropped out and every adverse event, even if it seemed unrelated to statins. Then they calculated ratios that translate to the likelihood of each adverse even occurring for every year a patient used the statins. This helped them to picture how often the effects happened and if it were more than you would expect to occur by chance. The team also used a statistical test to calculate the false discovery rate so they could spot which so-called adverse events were really down to the statins.
Fewer Side Effects of Statins Than Expected
After exhaustively digging into the side effects and adverse event reports, the researchers came up with a list of 66 side effects or adverse events that manufacturers list on statin packets. These ranged from sexual dysfunction to kidney failure with many stops along the way.
The team analysed data from 123,940 people, whom researchers followed for a median of 4.5 years. After crushing the numbers, they found that, with the exception of myopathy, diabetes, liver function tests and urinary composition, none of the other 62 side effects showed up in patients using statins any more than people using placebos.
When it came to liver function test results, the team did see some effect from statins at high doses. On the other hand, they didn’t see any evidence that people were showing signs of liver injury, for example, jaundice or hepatitis or liver failure, any more frequently than did the placebo group. So while test results showed some changes in certain enzymes, it’s not clear whether that actually matters. What’s more, the reduction in a person’s risk of developing MASH (AKA non-alcoholic steatohepatitis) when they take statins far out weighs the risks linked to statins.
Likewise, when the researchers looked closer at the unusual urine test and oedema results, they didn’t appear to correspond to any known ill effects.
Making Informed Choices
So if you’ve been on the fence about dropping off that script with your pharmacist, the takeaways are that the vast majority of statin side effects listed on the packaging are not something to worry about. Even the adverse events with a real link to statins are very rare and not serious. Folk who use statins are 7% more likely to have mild muscle pain, have a teeny tiny increase in blood glucose concentration and an even smaller probability of having a weird liver or urine test.
In contrast people who use statins lower their chances of a cardiovascular event by 90% and halve their risk of dementia. The choice is yours, but make sure it’s evidence-based.
Sources
Mensah GA, Wei GS, Sorlie PD, et al. Decline in Cardiovascular Mortality. Circulation Research. 2017;120(2):366-380. doi:10.1161/CIRCRESAHA.116.309115
Cholesterol Treatment Trialists’ (CTT) Collaboration. Electronic address: [email protected], Cholesterol Treatment Trialists’ (CTT) Collaboration. Effects of statin therapy on diagnoses of new-onset diabetes and worsening glycaemia in large-scale randomised blinded statin trials: an individual participant data meta-analysis. Lancet Diabetes Endocrinol. 2024;12(5):306-319. doi:10.1016/S2213-8587(24)00040-8
Cholesterol Treatment Trialists’ Collaboration. Effect of statin therapy on muscle symptoms: an individual participant data meta-analysis of large-scale, randomised, double-blind trials. Lancet. 2022;400(10355):832-845. doi:10.1016/S0140-6736(22)01545-8
Assessment of adverse effects attributed to statin therapy in product labels: a meta-analysis of double-blind randomised controlled trials. Lancet. 2026;407(10529):689-703. doi:10.1016/S0140-6736(25)01578-8
The Benefits and Risks of Statins | University of Ottawa Heart Institute. June 23, 2014. Accessed October 15, 2026. https://www.ottawaheart.ca/the-beat/news/the-benefits-and-risks-statins
