In the ever-expanding world of wellness advice, where TikTok influencers and outdated medical brochures coexist, it’s easy to confuse health facts with fiction. The problem? Many persistent health myths sound plausible—some are even rooted in old research—but modern science tells a very different story. From how much water you really need to whether microwaves are dangerous, these misconceptions could be shaping your habits for the worse.
Let’s set the record straight on 18 common health myths you’ve probably heard, and may still believe.
Most people think getting a natural tan from the sun is safer than using a tanning bed. It feels intuitive—after all, sunlight is "natural," right? But dermatologists in the U.S. unanimously agree: there's no such thing as a safe tan, whether it's from the sun or a machine. Both expose your skin to harmful ultraviolet (UV) radiation, and prolonged exposure—especially without SPF—directly increases the risk of skin cancer. According to the CDC, skin cancer remains the most common cancer in the United States, and indoor tanning contributes to thousands of new cases each year. So, forget the “base tan” myth—it won’t protect you. A better investment? Broad-spectrum sunscreen and a wide-brimmed hat.
And speaking of myths that linger…
You’ve probably heard that cracking your knuckles leads to arthritis. This tale has been passed down like folklore at dinner tables for generations. But there’s no credible scientific evidence that links knuckle-cracking to arthritis. The popping sound comes from gas bubbles in the joint fluid—not from grinding bone. In fact, a California doctor famously cracked the knuckles on just one hand for over 60 years and found no difference in arthritis symptoms between the two.
Another persistent myth: that eating eggs will wreck your cholesterol. For decades, Americans were advised to avoid more than three whole eggs per week. But that advice was based on early understandings of cholesterol that didn’t distinguish between dietary cholesterol and blood cholesterol. Updated research now shows that moderate egg consumption—up to one per day—has no significant impact on heart disease risk for healthy individuals. Eggs, in fact, are an excellent source of protein, choline, and other nutrients. The 2020-2025 Dietary Guidelines for Americans have reflected this shift, softening restrictions on eggs and cholesterol.
Let’s also address the holy grail of hydration: the “8x8” rule—eight glasses of water, eight ounces each, per day. While staying hydrated is essential, this rule is overly simplistic. People have vastly different needs depending on their size, diet, climate, and activity level. A construction worker in Arizona and an office assistant in Maine aren’t going to need the same amount of water each day. A better rule? Listen to your body. Thirst is a reliable signal, and the color of your urine can be an excellent hydration indicator—aim for pale yellow.
Similarly, the idea that you need to take exactly 10,000 steps a day for good health is more marketing than science. That number originated from a Japanese pedometer campaign in the 1960s, not from clinical trials. While walking is undeniably beneficial, the most important thing is consistency, not a specific number. According to the CDC, adults need about 150 minutes of moderate-intensity aerobic activity per week. That could include walking, biking, dancing, or swimming—not just step-counting.
There’s also a damaging misconception that six-pack abs are the ultimate sign of health. Popular culture often equates visible abs with peak physical condition, but that’s misleading. Genetics play a huge role in fat distribution, and for some people, achieving that level of definition requires extreme dieting that may actually harm their metabolism or hormone balance. A strong core is more valuable than a shredded one. Think planks and functional movement over aesthetics.
One of the most controversial food myths still around is that saturated fat directly causes heart disease. For years, Americans were told to avoid butter, red meat, and cheese. While it’s true that high levels of LDL cholesterol are a risk factor, newer research has complicated the picture. A 2017 British Medical Journal study suggested that saturated fat may not clog arteries in the way we once believed. However, moderation is still key. The FDA recommends limiting saturated fat to less than 10% of daily calories—not because it's inherently evil, but because balance and variety matter more in long-term heart health.
When it comes to food choices, the “organic equals healthy” myth is one of the trickiest. Organic food is grown without synthetic pesticides and is often more expensive, but that doesn’t automatically make it more nutritious. A Stanford University review of over 200 studies concluded that there is little evidence to show a nutritional advantage. While organic produce may reduce your pesticide exposure slightly, the health impact of that difference remains uncertain. If your goal is better nutrition, focus on eating more fruits and vegetables of any kind—organic or not.
Let’s talk about sugar. A common belief is that natural sugars—like honey, coconut sugar, or agave—are healthier than white sugar. But from a metabolic standpoint, sugar is sugar. Your body processes them all similarly, whether they come from a trendy “raw” syrup or a standard bag of cane sugar. The real distinction lies in whether the sugar is part of a whole food (like fruit) or added to processed items. An apple provides fiber, vitamins, and antioxidants along with its sugar. A cookie, not so much.
Another myth that’s lost credibility over the years is that coffee stunts your growth. There’s zero scientific evidence to back this claim. Height is determined primarily by genetics, not caffeine. If you're sensitive to caffeine, it may affect your sleep—but it won't change your bones. In fact, moderate coffee consumption is now linked to several health benefits, including reduced risk of type 2 diabetes and Parkinson’s disease.
Genetically modified organisms (GMOs) often get a bad rap too. There’s a lot of fear-based misinformation online, suggesting that GMOs are harmful or carcinogenic. But long-term studies—including one published in the journal Critical Reviews in Biotechnology—have found no health risks from consuming GMOs. In fact, GM crops often require fewer pesticides and produce higher yields, helping address food insecurity in low-income countries. The FDA, WHO, and National Academy of Sciences all endorse the safety of approved GMO foods.
And what about that old tale that microwave ovens cause cancer? This myth likely stems from a misunderstanding of radiation. Microwaves use non-ionizing radiation—like radio waves—to heat food. It doesn’t change your DNA or alter the structure of your cells. In fact, the FDA strictly regulates the allowable radiation leakage from these devices. As long as your microwave isn’t visibly damaged, it’s perfectly safe.
A similar myth exists around antiperspirants and breast cancer, specifically the aluminum compounds they contain. Concern grew from early lab studies where high doses of aluminum affected isolated cells—but there’s no evidence that this translates to actual cancer risk in humans. The American Cancer Society has stated there’s no conclusive link between antiperspirants and breast cancer. Your deodorant isn't killing you. Use it with confidence—and for everyone’s benefit.
And then there’s the misconception that late-night exercise is bad for sleep. While it's true that intense cardio right before bed can keep some people alert, it doesn't apply to everyone. For many, working out in the evening has zero negative impact—and may even improve sleep quality. A study in Sports Medicine found that moderate evening exercise can help people fall asleep faster and enjoy deeper sleep, especially when the workout ends at least an hour before bedtime.
We live in an age where health advice is everywhere—but not all of it is based on facts. Between social media fads, outdated public health guidelines, and word-of-mouth rumors, misinformation can spread like wildfire. And while not every myth on this list is harmful, many can influence your decisions in ways that don’t benefit your long-term well-being.
Your best defense? Stay curious, ask questions, and seek out reliable sources like the CDC, Mayo Clinic, and peer-reviewed medical journals. After all, wellness isn’t about following trends—it’s about making informed choices that suit your unique body and lifestyle.