17 Most Dangerous Health Myths That Just Won't Go Away

From vaccines to vegan diets, medical experts debunk some common—and dangerous—myths.

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Every day, doctors do their best to disprove myths their patients have believed for years. While some of these misbeliefs are totally harmless in their less-than-factual nature—like "an apple a day keeps the doctor away"—others are downright dangerous, and believing them can seriously hurt your health—or even worse. From drastic home "remedies" to fight off COVID-19 that could land you in the hospital to believing that you aren't at risk for certain medical conditions, here are the most dangerous health myths that won't seem to go away, but need to be retired once and for all. And for more ideas you've been mistaking as facts, check out 50 Things You Always Believed That Aren't True.

1
Anyone with heart disease should avoid exercise.

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Those with heart disease might think being sedentary is the best option. But Richard T. Lee, MD, a cardiologist in Boston, MA, told Harvard Health that doing so is a really bad idea. "It can lead to blood clots in the legs and a decline in overall physical condition," he says. Physical activity, on the other hand, can do the opposite, helping keep your heart muscle healthy, improve blood flow, and improve your overall health, he says. And for more things that are harmful to your health, check out The 20 Worst Habits That Are Destroying Your Heart.

2
Heart disease only affects men.

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Sorry, ladies—heart disease affects you, too. Even though it's commonly thought of as a man's problem, Harvard Health notes that since 1984, more women have died every year from heart disease than men. But because it's the leading cause of death for both men and women over age 65 in the United States, no one should wait to improve their heart health. Focus on bettering it now by exercising, eating a healthy diet, not smoking, and limiting alcohol use. And for some things you can do to lower your risk of heart disease and other serious conditions, check out 100 Easy Ways to Be a (Much) Healthier Woman.

3
The flu shot gives you the flu.

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Some people avoid getting the flu shot every year because of a popular myth that the flu shot actually gives you the flu. According to the Centers for Disease Control and Prevention (CDC), that couldn't be further from the truth, as flu vaccines can't possibly cause flu illness. 

"The flu vaccine is made from an inactivated virus that can't cause infection with influenza," Candice R. Robb Rarey, DO, an internal medicine physician in Illinois, told Northwestern Medicine. "This helps your body build the antibodies it needs to fight the first sign of the influenza virus. It takes roughly one to two weeks for this to occur, so there is a chance you could contract the flu after the shot, but never because of the shot." And for another false fact about disease prevention, check out The Biggest Myth About the COVID Vaccine You Need to Stop Believing

4
The fewer calories you eat, the more weight you'll lose.

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When you're on a diet and trying to lose weight, you might think the best way to go about it is limiting your calories. Amy Gorin, MS, RDN, a plant-based registered dietitian in the New York City area, is here to tell you that's the worst thing you can do for your health.

"Here's a fact: Your body needs calories to function, and you're not going to benefit from continuously eating an extremely low amount of calories. I've had clients who thought they should be eating 1,200 calories or less every single day," she says. "Not only does your metabolism adjust to this new number—which is not a good thing!—but your body needs more calories than this to optimally function. You want energy to do a workout and to enjoy activities with your loved ones, right?"

5
Drinking bleach will cure COVID-19, cancer, autism, and more.

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For some reason, people have decided drinking bleach is a good idea. So much so that both the Centers for Disease Control and Prevention (CDC) and Food and Drug Administration (FDA) have had to issue public statements due to the increased number of calls to poison centers.

"An advisory was issued urging the public to stop drinking sodium chlorite solution, also known as a form of industrial bleach. This gained notoriety in online communities as the 'master/miracle mineral solution,' or MMS," says Sunitha D. Posina, MD, a board-certified internist in New York. "Its proponents claim the substance 'only targets pathogens, leaving healthy tissue alone, and thereby curing everything from malaria to cancer to autism.' But there's no scientific evidence to affirm the benefits, and drinking this mixture with activators such as lemon juice can lead to liver damage, dangerously low blood pressure, and other dire health circumstances."

6
Going vegan will make you protein deficient.

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Vegan and vegetarians get asked how they get enough protein on a plant-based diet all the time. Funny enough, it's one of the last things they need to worry about. In reality, Harvard Health says men should aim for 56 grams per day while women should aim for about 46 grams daily, and most people—vegans included—get more than enough without even trying. By believing this myth, you could be missing out on some of the life-saving benefits of a plant-based diet, like a reduced risk of heart disease. Gorin says when you're eating plant-based, you can easily get enough protein by drinking protein-rich smoothies and eating nuts and nut butters, as well as loading up on things like tofu and tempeh.

7
Taking placenta pills can help with postpartum depression.

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You may have heard eating your placenta has some benefits after pregnancy, and because of that, people are taking placenta pills. But Niket Sonpal, MD, an internist and gastroenterologist in New York City, wants to set the record straight. "Supporters of the practice say that ingesting one's placenta helps speed up recovery from pregnancy, restores energy, and prevents postpartum depression," he says. "The problem is, there's no science or evidence to back up these claims that involve a severe—and sometimes even dangerous—psychiatric condition like postpartum depression."

According to Sonpal, the placenta is for keeping potentially dangerous toxins from reaching the fetus—not for consumption. "Placenta pills are not FDA-approved, supply only a minimal amount of iron, and wind up delivering the same toxins back to the mother." Yep, not great. And for more helpful information, sign up for our daily newsletter.

8
Drinking detox teas will help you lose weight.

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Nope, there's still not a magical way to lose weight, no matter how many detox teas your favorite celebrities—you know, the ones with personal chefs and trainers—swear they drink. "Detox teas don't cause real or long-lasting weight-loss results. In reality, they can dehydrate you, potentially cause severe damage to the liver and colon, cause you to develop a reliance on laxative drugs, and other worrying side effects," Sonpal says. "If someone you know appears to have lost weight using detox teas, it's likely due to water weight thanks to their laxative effects." And for more so-called shortcuts to shedding those extra pounds that you should steer clear of, check out 45 Weight Loss Tips You Should Never Listen To.

9
And juice cleanses are the way to go for sustainable weight loss.

Juice cleanses can backfire on you when you're losing weight
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Despite what you read on Instagram, juice cleanses aren't a good way to lose weight. "This is one of the health myths that drives me the craziest," Gorin says. "I recommend 100% juice as part of a balanced diet, but I would never recommend drinking only juice." Not only will you not get enough calories to energize you through your day, but she also says you aren't taking in all the nutrients your body needs from juice alone.

10
Ear candling can bring about many health benefits.

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You've probably heard of the many health claims of ear candling, be it treating sinus infections or relieving headaches. But Sonpal wants you to keep that wax far away from your ear canals. "There's no scientific evidence that ear candling works, but there is a lot that proves it's very dangerous," he says. "It can burn your skin, perforate your eardrum, and even push wax deeper into the ear. All of these can lead to severe consequences, such as infections, second or third-degree burns, and hearing loss. No audiologist would ever recommend this to any patient."

11
Alcohol warms you up in the cold.

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Unfortunately, loading up on drinks on a cold night out isn't actually going to warm you up, even if it feels like it in the moment. In reality, this is a dangerous myth to believe, as spending time out in the cold when you're drunk could increase your risk of hypothermia.  

"So many people believe that a shot of rum will warm them up when coming in from a cold winter's night. This is an absolute myth," Posina says. "Alcohol causes your blood vessels to dilate, moving warm blood closer to the skin and making you feel warm. But in reality, this causes you to actually lose body heat faster."

12
Cold, wet weather causes colds and the flu.

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You've probably heard this myth a million times growing up, and Sonpal wants you to know it's not true. "Weather alone can't cause someone to get sick. Infectious illnesses come from bacteria and viruses, not cold weather," he says. While he does note that it's important to protect yourself against cold temperatures for other reasons—like frostbite, for example!—it's not the cause of the cold or flu. "People who genuinely believe this is what causes colds and the flu may not understand how germs affect the body and how to protect themselves against diseases year-round."

13
You should put ice on a burn.

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If you burn your skin, you want to put something cold like an ice cube on it, right? Wrong. "Ice can damage cells and has also been shown to make burns worse. The same goes for butter: It's an effective conductor of heat, so it will actually make a burn worse," Posina says. "The majority of damage from a burn is caused by the skin's inflammatory response to it. The best way to keep a partial-thickness burn from going to full-thickness is to immediately immerse the burn in cool water."

14
If diabetes runs in your family, there's no reason to try and be healthy.

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Oftentimes, people with a family history of a chronic disease like type 2 diabetes decide not to care because they think they're destined to have it, too. But that's not the case, and Gorin wants to set anyone in this predicament straight before they actually do hurt their health. "Take your health into your hands right now. Eat healthy, balanced meals, lower your intake of added sugar, exercise on the daily, and focus on getting quality sleep," she says. "All these little things will add up to a healthy lifestyle that will help reduce your disease risk."

15
Vaccines are dangerous and can cause autism.

black baby with father getting vaccine from white female doctor
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As a doctor, it's not uncommon to have patients who believe all the myths out there about vaccines. Unfortunately, those who do could be hurting their children. "This has been a very controversial topic for a long time. Parents can feel uncomfortable about their children being 'overloaded' with injections and what effect that might have health-wise," Posina says. "The good news is that the immune load of the current vaccines is a fraction of what it was three decades ago. Science has become more precise at teaching the immune system to fight disease."

Posina says many parents are concerned about thimerosal—a preservative used in older vaccines—because of a debunked myth that it's linked to autism. "However, this has not been in use since 2002," she says. "With the way modern medicine has progressed, the danger of not vaccinating your children as recommended by their pediatrician and the CDC is far greater." 

16
The only way to lower your blood pressure is with medicine.

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Sometimes medicine is required in order to lower your blood pressure, but people often forget that what you eat can make a big difference, too. "As a registered dietitian nutritionist, I believe food is medicine. And did you know that potassium-offering foods such as avocado, banana, and tomato help counteract the effects of sodium?" Gorin says. "That's not to say you can eat all the salt you want, but incorporating these foods into your daily diet and moderating your intake of sodium will only help your blood pressure."

17
You only need to wear sunscreen when the sun is shining.

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While many people believe sunscreen is only needed when they're out in the sun, that's not the case and can put you at risk of skin cancer. In reality, you should be wearing it every day, year-round—even when the sun isn't shining.

"Wearing sunscreen on a cloudy day is just as important as wearing it on a sunny day," Lara Devgan, MD, a plastic surgeon and skincare expert in New York City, wrote on her website. "The sun's rays usually are a sign to most people that the skin needs protection from a sunburn, however, on cloudy days, UV rays may be just as prevalent, even if the sun isn't visible. Even on a cloudy day, you may get sunburned by UV rays."

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