High cholesterol is a prime example of having too much of a good thing. Our bodies naturally make this substance in the liver and then transport it throughout the body for multiple functions, including hormone regulation, cell tissue regeneration, and vitamin absorption. When the system is working well, cholesterol can boost overall health. But when a certain type called low-density lipoprotein—LDL, sometimes dubbed the “bad” kind—is overproduced, not only does it block the “good” kind called high-density lipoprotein (HDL), but it can also begin to accumulate in the arteries and form thick, hard deposits. This narrows the space for blood flow and raises the risk of blood clots, which can lead to heart attack or stroke. The U.S. Centers for Disease Control and Prevention (CDC) notes that about 93 million American adults have high cholesterol, which represents about 36% of the U.S. adult population.

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High cholesterol rarely presents with symptoms in its early stages, which is why knowing your cholesterol levels and reducing LDL if it’s getting too high is crucial for heart health. For many people, a type of medication known as statins may be a recommended step for cardiovascular risk prevention. First approved by the U.S. Food and Drug Administration in 1985, these drugs work by blocking a substance your body uses to make cholesterol, which can reduce the level of LDL cholesterol and also help stabilize the plaques on blood vessels so they don’t break off and become problematic.

According to the CDC, statin use has been growing for the past decade, and nearly 39 million Americans take a statin daily. Usage increases over age 40 since heart risks tend to escalate as we get older. However, a statin prescription isn’t a guarantee for everyone.

Here are answers to five key questions about this common medication, along with advice on when to talk to your doctor.

How do statins work?

Much like lowering production in a factory, statins work by reducing the amount of cholesterol produced by the liver. They also help the liver remove cholesterol already in the blood, which can reduce the chances that you’ll develop deposits in the arteries.

This differs from other types of cholesterol-lowering medications because rather than trying to eliminate excess cholesterol once it’s manufactured, statins target the source of that production.

For example, injectable medicines called PCSK9 inhibitors lower cholesterol by blocking the LDL receptors in the body, resulting in how much cholesterol circulates in the bloodstream. There’s also niacin, sometimes called nicotinic acid, which works by raising HDL cholesterol levels—an action that lowers LDL cholesterol as a result.

Read More: What to Know About High Cholesterol in Kids

Has the thinking on who should get statins changed over the past few years?

As more statins have become available—there are now seven options—and usage of these medications has increased, scientists’ understanding of cholesterol and heart disease has also evolved, says Dr. Adriana Quinones-Camacho, a cardiologist at NYU Langone in New York.

“The more we learn about heart disease and cholesterol, the more nuanced the recommendations have become,” she notes. “In the past, the level of total cholesterol, and especially LDL, may have been the biggest consideration for statin use, but that’s not the case anymore.”

For example, age is an incredibly important variable. Research published in the journal Clinical Epidemiology in 2016 suggests the statin prescription rate has increased the most for people ages 50 to 59, while slowing slightly for those ages 60 to 74.

Research within the past decade has also clarified the strong association between diabetes and heart disease, especially if someone also has high cholesterol. If you have diabetes, you’re already twice as likely to have heart disease or experience a stroke—and at a younger age—than someone without the condition. Additional factors like cholesterol and high blood pressure could make it much more likely that your doctor would suggest a statin, says Quinones-Camacho.

“As we have more data and evidence about cholesterol’s effect on the body, as well as research on these other variables, it gives us more information we can use to tailor our recommendations around statins for each patient,” she adds.

Would someone with high cholesterol automatically be a candidate for statins?

In August 2022, the U.S. Preventive Services Task Force recommended that people aged 40 to 75 who are at high risk of cardiovascular disease should consult with a health care professional about taking a statin to prevent a first heart attack or stroke.

Although high LDL and low HDL numbers are two of the main considerations when it comes to statin recommendations, they’re not the only ones, says Dr. Kevin Ferentz, chair of the department of family medicine and lead physician at GBMC Health Partners Primary Care in Maryland.

“High cholesterol is only one factor in the development of heart disease,” he says. “Others—like smoking, high blood pressure, and diabetes—play a role as well.” A physician will consider your age, general physical condition, family history of heart issues, and presence of other chronic illnesses, adds Dr. Jennifer Wong, a cardiologist and medical director of non-invasive cardiology at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in California.

Combining all of these factors isn’t done through intuition—there’s a standardized risk calculator used by health professionals that looks at nine different factors and calculates the 10-year probability of heart disease development. In some cases, Wong says, this score can prompt people to make important lifestyle changes that might lower their risk without the use of medication.

Most notably, quitting smoking is a huge benefit to cardiovascular health that may drop LDL cholesterol on its own. When combined with healthy eating and regular exercise, it’s possible a patient may get cholesterol levels into a better range within just a few months, while also improving their blood pressure and diabetes symptoms if either of those are present.

However, the variables that can’t be changed—like genetics and age—may be more prominent and increase risk to the point of making statins advisable, Wong says. And one factor that almost always drives statin recommendations? Having a prior heart event.

“If someone has experienced a heart attack or stroke, they will very likely be a candidate for statins, regardless of their cholesterol level,” she says. “If they also have hypertension or diabetes in addition to a heart event, they will almost certainly be advised to take statins.”

Read More: How to Lower Your Cholesterol Naturally

What are the most prevalent side effects?

Considering that statins have been increasingly used for nearly 40 years, there’s ample data on side effects as well as the balance of reward versus risk, Ferentz says. In general, statins tend to be well tolerated, and the majority of people taking them have no side effects, particularly if they’re well monitored.

Some people who start statins experience elevated blood sugar levels. For most people, this isn’t a concern, Wong says, but if you’re prediabetic and that slight elevation increases the risk of developing Type 2 diabetes, that may require a treatment change. However, she adds, the conversation with your health provider will center around whether the benefit of taking a statin may outweigh the risk.

Beyond that, doctors typically check liver function before people start a statin, and again on an annual basis. “Statins occasionally do raise liver function concerns,” Ferentz says. In certain cases, like if a patient is experiencing liver damage, statins might be discontinued completely and replaced with other medications.

The main side effect associated with statins is myopathy, a neuromuscular disorder that causes muscle pain. Statin-associated muscle symptoms can include mild-to-moderate pain, fatigue, weakness, and night cramps, and can be confirmed via a blood test.

Research suggests that up to 25% of people on statins experience some type of muscle issues. In rare cases, this can progress to more serious conditions such as rhabdomyolysis, in which damaged muscle tissues release compounds like protein and electrolytes into the blood, potentially affecting the kidneys and heart.

However, that occurs only if muscle pain goes untreated, says Wong. Most people who are experiencing higher levels of discomfort and side effects can be switched to a different statin or even a non-statin cholesterol-lowering option that may resolve muscle problems.

“Every medication has side effects, and statins are no exception,” Wong adds. While muscle pain is the most common complaint, she also hears about sleep difficulties, digestive troubles, and dizziness. “In all these instances, we’re fortunate to have several types of statins available,” she says. “So it’s easy to change to one that might work better. Sometimes, just lowering the dosage can have a major effect.”

When should you talk to your doctor?

Even if you’re generally healthy—you don’t have any other chronic conditions, you eat healthy, you don’t smoke, and you exercise regularly—you can still have high cholesterol. Keep in mind that it rarely presents with symptoms. Getting your cholesterol checked after age 40 is crucial, but Quinones-Camacho suggests knowing your numbers decades before that, too.

Most likely, younger people won’t be put on statins, but having a baseline for your cholesterol levels to monitor can help lower heart-health risks overall.

Regardless of your age, talk to your doctor if you have a family history of heart disease. You’ll also want to stay on top of your cholesterol numbers if you smoke now or did in the past, or if you have high blood pressure, diabetes, less-than-ideal nutrition, or sedentary behavior.

“In the end, like everything in medicine, statin use will come down to what’s best for an individual,” Quinones-Camacho says. “Two people of the same age with the exact same cholesterol numbers may be managed very differently in terms of cholesterol-reduction plans.” As with everything else in medicine, prevention is preferable to treatment. “So the earlier you talk to your doctor, the better.”