TIME Research

You Asked: Are Self-Tanners Safe?

You Asked: Should I Use Spray Tanner?
Illustration by Peter Oumanski for TIME

These products are safer than sun exposure—but only if you avoid the sprays.

To bake, or to fake? It’s a classic tanning conundrum. Sitting under the sun causes skin damage and cellular changes that raise your risk for skin cancer, and even among adults under 40, melanoma rates are on the rise.

“In order to get a natural tan from ultraviolet light, your skin has to be injured,” says Dr. Darrell Rigel, a clinical professor of dermatology at New York University. You know this, and you worry about it. But unlike ultraviolet rays, sunless self-tanners don’t mean you have to damage your skin. “These products contain an ingredient that stains the outermost layer or your skin,” Rigel says.

In most cases, that ingredient is dihydroxyacetone (DHA). When it combines with amino acids in your skin, DHA causes a browning reaction—the same type of reaction that occurs when you make toast or grill meat, explains Dr. Adam Friedman, director of dermatologic research at Montefiore-Albert Einstein College of Medicine.

That may sound scary. But the browning only takes place in your skin’s “stratum corneum”—the topmost layer composed of dead cells, Friedman says. “Our bodies make a form of this stuff,” he adds, referring to DHA. “So I’m not concerned about it from as safety standpoint. When used topically, I think it’s the only safe way to have a tan appearance.”

For anyone who’s read up on self-tanners, Friedman’s statements may raise eyebrows. A few years ago, a much-cited report from ABC News raised concerns about spray-tanning salons and the risks of inhaling DHA and other self-tanning ingredients. Subsequent research supported the idea that inhaling spray-on tanning chemicals could potentially raise your risk for asthma, chronic obstructive pulmonary disease (COPD) or cancer.

“Stretched flat, your lungs are the size of a tennis court,” says Dr. Reynold Panettieri, a professor of pulmonary medicine at the University of Pennsylvania. “So inhaling these self-tanning agents could have all sorts of potential health consequences.”

But what about self-tanners you spread on your skin? The ABC News report cited Food & Drug Administration data suggesting that small amounts of DHA might seep through your skin and into your bloodstream. If true, that could also raise health concerns. But since that FDA data came to light, follow-up studies have failed to find evidence that DHA penetrates your skin’s protective barriers.

Dr. Rigel was one of several experts who voiced concern to ABC News following their DHA investigation. But when it comes to DHA in lotions, Rigel says his concerns have since been assuaged. “There’s no data to show that DHA is harmful when applied topically,” he says. “Pregnant women and children may want to avoid it just as a precaution, but this is benign stuff.”

Panettieri agrees. “Based on what we know today, DHA is really pretty safe when applied to the skin correctly,” he says. Correct application means avoiding the sensitive skin around your eyes and on your lips, as well as cuts or abrasions—more reasons to be wary of spray-on options. Panettieri says rubbing DHA into very thin or broken skin could let it enter your system. “Even if DHA got beyond the skin, any risk is hypothetical,” he’s quick to add.

Both he and Rigel say that compared to the well-established risks of sun exposure, topical self-tanning lotions are a safer option. Friedman agrees, and says his only concern is that some people might have an allergic reaction to DHA or other ingredients in self-tanners—a risk that comes with almost any cosmetic.

But Friedman adds one big warning: Self-tanners do not offer your skin any protection from sun damage. “Some people think these self-tanners act like sunscreen,” he says. “They don’t.” In fact, some research suggests DHA may actually increase the amount of damage your skin sustains from sun exposure.

Of course, new research could always surface new risks. And not as much is known about less-common tanning chemicals. But for now, if you’re craving a little color, self-tanning lotions with DHA seem to be your safest option.

TIME Healthcare

You Asked: Why Are My Teeth So Sensitive?

You Asked: Why Are My Teeth So Sensitive?
Illustration by Peter Oumanski for TIME

Sometimes teeth are just touchy. But certain sensitivities are signs of trouble.

You feel it when you sip a hot drink or bite into a cool dessert: an ache, an acute stab of pain. Even a sharp breath of cold air might trigger a twinge. “Any tooth sensitivity is trying to tell us something,” says Dr. Matt Messina, an Ohio-based dentist and spokesperson for the American Dental Association. “It may be easy to treat, but something is still causing it.”

For dentists, the most common (and least alarming) sensitivity is an all-over reaction to very cold stimuli, Messina says. Especially if that cold-induced pain is short-lived, you probably don’t have reason to worry. But if the pain is persistent and confined to a specific tooth or area of your mouth, that’s a problem. “That’s often the sign of a micro-crack, a degraded filling or a cavity,” Messina says.

Those conditions, all of which require a dentist’s attention, become more probable if the tooth or area is also sensitive to heat and biting pressure. “If you have reactions to all three—cold, hot, and biting pressure—we could also be talking about some sort of infection in the tooth,” Messina adds.

If you’re dealing with an all-over ache, your gums—not your teeth—may explain your pain. Exposing your gums to irritants or harsh treatment makes them recede. And when they do, they leave exposed the tender roots near the base of your teeth. “Your roots don’t have the same quality of protective enamel as your crowns, so they’re more sensitive,” says Dr. Eugene Ko of the University of Michigan’s department of oral pathology.

Brushing too forcefully, chewing tobacco or allowing the buildup of plaque can all cause your gums to “run away” from your teeth, resulting in temperature sensitivity, Messina says. If you think gum recession might be the cause of your sensitivity, Ko says you may be able to look in a mirror and spot the issue. “The margin where your teeth and gums meet: there may be a change in color, almost like water elevation marks during a drought.”

Of course, there are many more reasons for temperature-sensitive teeth. Those include the excessive use of mouthwash or whitening products, dead or dying nerves, tooth grinding, recent dental work or serious gum issues like gingivitis or periodontal disease. Messina also says eating lots of acidic foods—things like soda, sports drinks, sour candy or citrus fruits and juices—can lead to a loss of tooth enamel that renders your teeth sensitive to temperature.

Apart from ditching those foods, Messina advises carefully reading and following instructions when using whiteners, mouth rinses, or other dental hygiene treatments. “More is not always better,” he warns.

When it comes to brushing, apply gentle pressure with a soft-bristle toothbrush. “You’re trying to massage you teeth all the way to the junction where they come together with your gums,” Messina says. “You should not be scrubbing like you would tub grout.” If changing your brushing technique doesn’t do the trick, he says switching to a sensitive-teeth toothpaste can help. “These contain a chemical agent that fills tubules in teeth and blocks sensitivity,” he says.

No matter what, you should mention the temperature issue to your dentist during your next visit. “Big problems often start out as sensitivities,” Messina says. “The solutions are often simple, but only if we address the problem early.”

TIME Mental Health/Psychology

You Asked: Are My Devices Messing With My Brain?

You Asked: Are All My Devices Messing With My Brain?
Illustration by Peter Oumanski for TIME

Yes—and you're probably suffering from phantom text syndrome, too.

First it was radio. Then it was television. Now doomsayers are offering scary predictions about the consequences of smartphones and all the other digital devices to which we’ve all grown so attached. So why should you pay any attention to the warnings this time?

Apart from portability, the big difference between something like a traditional TV and your tablet is the social component, says Dr. David Strayer, a professor of cognition and neural science at the University of Utah. “Through Twitter or Facebook or email, someone in your social network is contacting you in some way all the time,” Strayer says.

“We’re inherently social organisms,” adds Dr. Paul Atchley, a cognitive psychologist at Kansas University. There’s almost nothing more compelling than social information, he says, which activates part of your brain’s reward system. Your noodle is also hardwired to respond to novel sights or sounds. (For most of human history, a sudden noise might have signaled the presence of a predator.) “So something like a buzz or beep or flashing light is tapping into that threat detection system,” he explains.

Combine that sudden beep with the implicit promise of new social info, and you have a near-perfect, un-ignorable stimulus that will pull your focus away from whatever task your brain is working on. And while you may think you can quickly check a text or email and pick up that task where you left off, you really can’t.

“Every time you switch your focus from one thing to another, there’s something called a switch-cost,” says Dr. Earl Miller, a professor of neuroscience at Massachusetts Institute of Technology. “Your brain stumbles a bit, and it requires time to get back to where it was before it was distracted.”

While this isn’t a big deal if you’re doing something simple and rote—making an omelet, say, or folding clothes—it can be a very big deal if your brain is trying to sort out a complex problem, Miller says.

One recent study found it can take your brain 15 to 25 minutes to get back to where it was after stopping to check an email. And Miller’s own research shows you don’t get better at this sort of multitasking with practice. In fact, people who judged themselves to be expert digital multitaskers tended to be pretty bad at it, he says.

“You’re not able to think as deeply on something when you’re being distracted every few minutes,” Miller adds. “And thinking deeply is where real insights come from.”

There seems to be an easy solution to this: When you’re working on something complicated, switch off your phone or email.

That could work for some people. But there’s evidence that as your brain becomes accustomed to checking a device every few minutes, it will struggle to stay on task even at those times when it’s not interrupted by digital alerts. “There’s something called ‘phantom text syndrome,’ ” Atchley says. “You think you hear a text or alert, but there isn’t one.”

While phantom texts can afflict adults, Atchley says this phenomenon is pretty much universal among people under the age of 20—many of whom wouldn’t recognize a world that doesn’t include smartphones. Even if you don’t hear phantom alerts, you may still find yourself reflexively wanting to check your device every few minutes for updates, which disrupts your concentration regardless of whether you ignore that impulse.

Your ability to focus aside, a 2014 study appearing in the journal PLOS One found that people who spend a lot of time “media multitasking”—or juggling lots of different websites, apps, programs or other digital stimuli—tend to have less grey matter in a part of their brain involved with thought and emotion control. These same structural changes are associated with obsessive-compulsive disorder, depression, and anxiety disorders, says that study’s first author, Kepkee Loh, who conducted his research at University College London.

Atchley says more research suggests lots of device use bombards your brain’s prefrontal cortex, which plays a big role in willpower and decision-making. “The prefrontal cortex prevents us from doing stupid things, whether it’s eating junk food or texting while driving,” he explains.

He says this part of the human brain isn’t “fully wired” until your early 20s—another issue that has him worried about how a lot of device use may be affecting children and adolescents.

So what’s the antidote? Spending time in nature may counteract the focus-draining effects of too much tech time, shows research Atchley and Strayer published in 2012. Meditation may also offer focus-strengthening benefits.

Strayer says putting your phone on silent and setting your email only to deliver new messages every 30 minutes are also ways to use your devices strategically and “not be a slave to them,” he adds.

Of course, there are plenty of benefits associated with the latest and greatest technologies. Ease and convenience of staying in touch with friends is a big one. But many open questions remain when it comes to the true cost of our digital distractions.

“Imagine Einstein trying to think about mathematics at a time when part of his brain was wondering what was going on with Twitter,” Atchley says. “People make incredible breakthroughs when they’re concentrating very hard on a specific task, and I wonder if our devices are taking away our ability to do that.”

TIME Pain

You Asked: Do High Heels Actually Damage My Feet?

You Asked: Do High Heels Actually Damage My Feet?
Illustration by Peter Oumanski for TIME

Yep. And the damage doesn’t end at your toes.

High heels hurt. If you’ve worn them (I have not) then you probably know this already. But are high heels also bad for you? A 2014 survey from the American Podiatric Medical Association—composed of the nation’s top foot and lower-leg docs—found heels were far and away the most common cause of foot pain among women.

Unsurprisingly, much of that pain comes from contorting your foot into a steep “plantarflexed” position, concludes a study from the Journal of Applied Physiology. Like standing on your tiptoes for hours, that high-heeled posture may lead to painful muscle fatigue and strain injuries, the authors of that study say.

Calluses, blisters, bunions, and ingrown nails are all common among high heel wearers, adds Dr. Rodney Stuck, division director of podiatry at Loyola University Chicago. The higher the heel, the more trouble you’re likely to run (or walk) into, Stuck says.

But the most significant risks of your high-heel habit may begin higher up your leg. According to research from the U.K. and Austria, lots of time spent walking in heels actually changes the structure of the muscles and tendons in your calves—and not for the better.

High heels lead to shorter muscle fibers and a toughening of the Achilles tendon, says Dr. Marco Narici, a professor of clinical physiology at the University of Nottingham (and coauthor of that study). Narici says these muscle changes reduce your ankle’s range of motion, and contribute to your risk for strains and sprains. Stuck says these sorts of muscle adaptations may also up your risk for other lower-body injuries. A sore ankle or leg you blamed on running may actually have more to do with your high heels, he says.

More research shows walking in heels puts a great deal of force on your kneecaps. This force can lead to the early onset of osteoarthritis, says Dr. Constance Chu, a professor of orthopedic surgery at Stanford.

Chu says this risk increases among heavier women. “Combining walking in very high heels for long periods of time every day with obesity and aging would be a perfect storm for knee osteoarthritis, as well as foot, back, and other joint problems,” she says.

Of course, tossing your stilettos is the one surefire way to dodge all these potential health hazards. But if you’re not willing to part with your pumps, Chu says lower heels lowers your risk. For formal or work events when you feel heels are a must, she recommends wearing flats beforehand and changing into your heels only when you’ve arrived at your destination. “Taking time to sit and move the knees through a full range of motion may also be helpful,” she says.

Loyola University’s Stuck also suggests standing against a wall or with one foot on a step and stretching your feet for a few minutes every day.

But don’t swap your heels for flip-flops. An Auburn University study found the way those loose summer sandals shorten your gait and force you to grip with your toes may lead to all sorts of heel, ankle, and sole problems.

Feet sure don’t have it easy.

Read next: These High-Tech High Heels Change Color With the Click of an App

Listen to the most important stories of the day.

TIME Diet/Nutrition

You Asked: Do I Have a Gluten Allergy?

You Asked: Do I Have a Food Allergy?
Illustration by Peter Oumanski for TIME

What you eat could be the cause of your headaches, joint pain, sluggishness or dozens of other ailments. Or maybe not.

People tend to conflate the terms allergy, intolerance, and sensitivity when they talk about food-related reactions, and especially gluten. The first two refer to well-understood digestive disorders with predictable symptoms, says Dr. Robert A. Wood, division chief of allergy and immunology at Johns Hopkins.

If you have a true allergy, your immune system produces antibodies designed to protect you from something it sees as a threat—be it nuts or shellfish. Even a little nibble can cause cramping or stomach pain, a runny nose, skin rashes, or swelling and breathing issues, Wood says.

An intolerance is an inability to properly digest or absorb specific foods or nutrients, often due to a lack of one or more digestive enzymes. (For example, people who are lactose intolerant don’t have the enzymes required to break down lactose.) This inability can lead to gastrointestinal problems like stomach pain, vomiting or diarrhea. Wood says food intolerances, unlike allergies, tend to be “dose dependent”—meaning the more of the food you eat, the worse you feel.

Take gluten, a type of protein found in grains like wheat, rye and barley. When it comes to gluten-related health concerns, says Dr. Alessio Fasano, director of the Center for Celiac Research at Massachusetts General Hospital, roughly 1% of the population has celiac disease—a condition that causes a sufferer’s immune system to attack the small intestine whenever gluten is present. A smaller percentage of people, maybe 0.5%, have a related wheat allergy. “We can verify each of these through blood tests and screening,” Fasano adds. Blood tests are the first step in identifying the underlying condition; to get a definitive diagnosis, a gut biopsy is usually required. For people with these conditions, cutting gluten or wheat is an absolute necessity.

But unlike allergies and intolerances, food sensitivities occupy a gray zone. Like an allergy, they may be related to immune reactions. But they’re poorly understood and symptoms are hard to pin down, says Fasano. “If you believe reports, a food sensitivity could cause a stomachache one time, then a headache, then joint pain or even cognitive problems,” Fasano says.

Because the mechanisms underlying sensitivities aren’t known, Fasano says there’s no way to test and validate them. That ambiguity has led to a lot of confusion and disagreement among researchers, while creating ideal conditions for spurious health “experts” to push food elimination diets that may do more harm than good, he says.

Eliminating gluten is the most common (and some would say trendy) example of this, Fasano says. Some estimates suggest a third of Americans are trying to avoid or altogether ditch gluten. “There’s this misconception that gluten-free foods are healthier or somehow linked to weight loss,” Fasano says. “But for most people, going gluten-free probably will not be beneficial.”

There may be another category of people who suffer from a sensitivity to wheat or gluten. Some popular books have suggested, in the words of Grain Brain author David Perlmutter, that gluten “represents one of the greatest and most under-recognized health threats to humanity.” But there’s not much data to support such claims. Fasano says what data there is point to stomach or abdominal pain as the most common symptom of gluten sensitivity, followed by skin conditions like eczema. While foggy thinking and fatigue are tied to gluten, there’s no agreed-on explanation for these symptoms, Fasano says.

Aside from celiac disease, Johns Hopkins’s Wood says that the medical science community is so convinced gluten isn’t a major health issue that there’s very little funding or interest in studying the subject further. “I think the bulk of people avoiding gluten are avoiding it unnecessarily,” he says. “Most doctors or people who’ve looked into it think it’s more of a lifestyle choice than a valid health issue.”

And when people claim to feel healthier after ditching wheat or gluten? “Lots of junk foods and snack foods contain gluten,” Fasano says. Some estimates show one-third of all grocery store items contain gluten—many of them the additive-stuffed, overly processed packaged foods nutritionists would love for you to eighty-six from your diet. “If you cut out those things, of course you’ll feel better,” Fasano says. “But it’s not because your body has a problem with gluten.”

While he doesn’t believe gluten is the health villain many have made it out to be, Fasano says food-related reactions are common, from gastrointestinal issues like stomachaches or cramps to non-GI issues like headache and joint pain. Fruit, beans, alcohol and many other common foods have been linked to symptoms of allergy or intolerance.

If you feel certain foods, including gluten or wheat, may be triggering pain or another type of physical reaction, Fasano recommends visiting a gastroenterologist or an expert dietitian—someone who can help you identify the source of your problem without putting you at risk for a nutritional deficiency.

“You wouldn’t take antibiotics or insulin without seeing a doctor first,” he says, “and you should take the same precautions when it comes to making changes to your diet.”

TIME public health

You Asked: Should I Use Antibacterial Soap?

Illustration by Peter Oumanski for TIME
Illustration by Peter Oumanski for TIME

Research shows they offer zero health benefits. But by changing the makeup of your skin and body bacteria, antibacterials may be fostering new health concerns—especially for kids.

Whoever said “cleanliness is next to godliness” would think pretty highly of modern-day America. Never before has a population so committed itself to rubbing, scrubbing, sterilizing and disinfecting itself from the grit and grime of the natural world. And for good reason: global trade and travel have allowed viruses to hop from country to country via innocent workers and tourists.

But while our zeal for cleaning is well-intentioned, our efforts are often misguided. In the case of antibacterials, we may be doing ourselves harm.

“Somehow, through marketing or misinformation, we’ve been led to believe that if we get rid of bacteria, we’ll improve our lives and our health,” says Dr. Martin Blaser, director of the Human Microbiome Program at New York University and author of Missing Microbes: How the Overuse of Antibiotics Is Fueling Our Modern Plagues. “In fact the opposite is probably true.”

Microbiologists are fond of pointing out that your body contains more bacteria than anything else; microorganisms populate your skin and gut by the trillions. “We live in a bacterial world,” Blaser says. “And the vast majority of those bacteria are neutral or beneficial. Very few are harmful.”

MORE: Antibiotics Overload Is Endangering Our Children

While much of his research has focused on the dangers associated with antibiotic drugs, Blaser is also concerned about the use of bacteria-killers in the home, especially where infants and children are concerned. “Early life is a critical time to build immunity and metabolism and cognition,” he says. “There’s more and more evidence that bacteria are a part of that development.” Remove some bacteria, and its possible you could be upsetting or altering that development in unpredictable ways.

There could be other consequences. “We’re seeing a greater number of antibiotic-resistant microorganisms over the periods these products have been around,” says Dr. Allison Aiello, an epidemiologist at the Gillings School of Public Health at the University of North Carolina. Aiello says there are known factors, such as antibiotic use in humans and animals, that have led to this uptick. But antimicrobial soaps containing triclosan may also be contributing to the appearance of these heartier organisms outside of healthcare settings, she says.

MORE: Antibiotic-Resistant Bacteria Are Now In Every Part of the World

At this point, there are still many gaps in the data on anti-microbial chemicals. But Aiello says various forms of triclosan—the chemical found in antibacterial hand soaps and body washes—may actually encourage the spread and strength of some bacteria by killing off others. She says there’s also some concern these chemicals may interact with human hormones in damaging ways. Those concerns led the state of Minnesota to ban triclosan from cleaning and personal care products.

“The potential risks definitely outweigh the benefits, which are none,” Aiello says.

You read that right. To date there is no evidence that washing and scrubbing your body and home with antibacterial products does any good.

One study split 1,000 households into two groups. While one of those groups received antibacterial cleaning products, the other got plain soap. Neither the researchers nor the participants knew which type of cleaner they were using.

“In terms of infection rates and sickness, we found absolutely no difference between antibacterial soap and regular soap,” says Dr. Elaine Larson, first author of that household study and director of the Center for Interdisciplinary Research on Antimicrobial Resistance at Columbia University.

Larson—working with Aiello—has reviewed dozens more research efforts that looked into the efficacy of antibacterials. Again, she and her colleagues found no benefit.

This doesn’t mean cleaning is unimportant, she says. Rather, the mechanical force—the act of rubbing your hands together under hot water, or scrubbing a cutting board with a brush—is what dislodges and cleans away harmful microbes; “The idea that soap kills germs is a misconception,” she says. “Soap just helps you wash germs off.” Regardless of the type of soap you’re using, Larson says “the rub is more important.”

Of course, there are times when true sanitization is necessary, Larson says. A doctor performing surgery is one of those times. People who have weakened immune systems may also require special consideration. But even in those circumstances, Larson says an alcohol-based sanitizer—not antibacterial soap—is needed to wipe out potentially harmful germs.

“This mythology has developed that we can sterilize the world, and that that’s a good thing,” Blaser says. “But the question should be, what’s the benefit? With many antibacterials, there isn’t one.”

TIME Research

You Asked: Are the Honeybees Still Disappearing?

You Asked: Are Honeybees Still Disappearing?
Illustration by Peter Oumanski for TIME

Beekeepers continue to grapple with historically high death rates. And now something’s up with the queens.

From almonds to cherries, dozens of food crops are partially or totally dependent on honeybee pollination. And while media attention has waned, there’s still reason to worry about the country’s smallest and most indispensable farm workers.

Bee researchers first reported massive die-offs back in the 1990s. But the plight of the honeybee didn’t truly buzz into the national consciousness until the spring of 2013, when data revealed the average beekeeper had lost 45% of her colonies the previous winter. A mysterious phenomenon known as colony collapse disorder (CCD) further stoked the fires of public interest.

Jump to 2015. While last winter’s bee death data won’t be published for a few more weeks, things appear to be “status quo,” says Dr. Greg Hunt, a honeybee expert at Purdue University. Unfortunately, the status quo is grim. “We’ve been seeing about 30% loss in an average winter,” Hunt says. “The winter before last was particularly bad and got a lot of attention, but things have been bad for a while.”

Dr. Dennis vanEngelsdorp—a University of Maryland entomologist who helps collect and publish the winter death data each spring—says there are three “primary drivers” of honeybee loss: The varroa mite, pesticides and poor nutrition. He doesn’t hesitate when asked to name the largest threat to bees: “I’d get rid of the varroa first.”

Varroa mites, properly (and frighteningly) named Varroa destructor, likely migrated to the U.S. sometime in the 1980s. They attach to a honeybee’s body and suck its blood, which kills many bees and spreads disease to others. The varroa can jump from one colony to another, wiping out whole populations of honeybees, vanEngelsdorp explains. There are treatments that combat the varroa. But many small-scale beekeepers don’t use them. “That’s bad, because they can spread mites to neighboring colonies,” he adds.

Of the two other major bee-killers vanEngelsdorp listed, pesticides have arguably gotten the most press—especially a commonly used category called neonicotinoids. While considered safe for humans, research suggests neonicotinoids may be extremely harmful to bees and many other insects, and so have been banned in some European countries. But the amount these chemicals contribute to bee deaths and colony collapse disorder is still debated. “We don’t find levels of neonicotinoids that are indicative of widespread exposure or harm,” vanEngelsdorp says.

The third problem—poor nutrition—is likely the most confounding of the honeybee’s enemies.

“Bees need a varied diet of different pollens in order to grow into strong, healthy workers,” explains Dr. Heather Mattila, a honeybee biologist at Wellesley College. Unfortunately, a country once filled with meadows of diverse, pollen-packed wildflowers is now blanketed by crops, manicured lawns, and mown fields barren of pollen sources. “A green space can be a green desert if it doesn’t have flowering plants that are bee-friendly,” Mattila adds.

Combine a restricted diet with environmental factors like extremely cold winters and scorching summers, and stressed honeybee colonies are less able to resist the ravages of mites, pesticides, viruses and other potential causes of colony collapse disorder.

To fill nutrition gaps, beekeepers give their wares pollen supplements. Along with tactics like colony splitting, keepers can restore their bee supplies quickly during the spring and summer months. But Hunt says the cost to do this is large—and growing larger. “As long as beekeepers are willing to put more money and hard labor into it, we can come back and rebuild our colonies and numbers,” he explains. “But whether this is all sustainable is an open question.”

Mattila calls this a “Band-Aid,” not a cure. “I think we’re making the best of a tough situation,” she says. Both she and Hunt applaud companies and localities that have started letting wildflowers grow along the sides of highways or under rural power lines—places that used to be mown and sprayed with herbicide. The federal government has also taken steps to protect lands that offer honeybees (and lots of other insects) the sustenance they need. Mattila says every American can help these efforts by planting flowers and avoiding chemical treatments.

But she mentions another emerging concern when it comes to the future of America’s honeybees: The strange, abrupt deaths of many bee queens. “When I started working with bees 18 years ago, we’d replace living queens every two years,” she recalls. “Now queens die after half a summer. Nobody is really clear on why.”

The “Band-Aid” she mentioned might already be coming off.

Read next: You Asked: Do Fruit Flies Come From Inside Fruit?

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TIME medicine

You Asked: Why Is My Hair Falling Out?

You Asked: Why Is My Hair Falling Out?
Illustration by Peter Oumanski for TIME

Drugs can help. But a lasting solution might require lifestyle changes.

First, let’s debunk a few myths: Shampooing, brushing and towel drying your hair aren’t making it fall out. “People associate these things with hair loss because they see the hair come away. But these aren’t the cause,” says Dr. Melissa Piliang, a dermatologist with the Cleveland Clinic. In fact, Piliang says shampooing less frequently may make things worse. “It can lead to dandruff and scalp inflammation, which can exacerbate hair loss,” she says.

Hats and ponytails also get a bum rap. “If a ponytail is worn so tightly it pulls on your eyes, that could damage your hair and lead to breakage,” Piliang acknowledges, adding that tight braiding, extensions and weaves—which yank on small groups of hair follicles—can also cause problems. “But generally wearing a ponytail or a hat won’t cause hair loss,” she says.

Men and women lose their hair for different and interrelated reasons, ranging from genetic factors to a poor diet, says Dr. Adam Friedman, director of dermatologic research at the Montefiore-Albert Einstein College of Medicine in New York. “It’s rare for hair loss to be caused by just one thing,” he says.

To understand these causes, it’s helpful to know how your hair works. Similar to the way your skin’s cells turn over, your hair is constantly sprouting, growing and falling out. Guys with healthy hair shed between 60 to 80 follicles a day, while women lose roughly 100, Friedman says.

When it comes to male- and female-pattern baldness—the most common types of hair loss—certain hairs grow in shorter and shorter over time, and eventually stop growing back at all. This is usually the result of a genetic sensitivity to hormones in the skin, Friedman says. “In men, you see this most in the front and sides of the scalp,” he explains. “In women, it’s more centrally located and diffuse.” Friedman says this is a slow process, one that can take years to become apparent.

For these people, drugs that block the production of skin hormones or keep hairs from falling out—such as minoxidil and finasteride—tend to work well, Friedman says. But both are better at stopping hair loss than they are at regrowing hair. “If you’re bald and want treatment, there’s often not much you can do,” he says. For this reason, it’s imperative that you see a doctor as soon as you notice a problem.

Poor nutrition is another potential contributing factor. Friedman says low levels of iron, vitamin D, some B vitamins and zinc have all been linked to hair loss. While typically not the main cause of your thinning mane, nutrient or vitamin deficiencies can make the problem worse, he says. Fixing your diet or taking supplements can help, but it’s often just one part of a multifaceted solution.

If clumps come out when you shower or you notice thinning in just a few weeks or months, you’re more likely dealing with another common condition called acute telogen effluvium, Piliang says. This rapid hair loss is basically a short-term ramping up of your hair’s normal shedding process.

Any event that puts a lot of stress on your body—like childbirth, surgery or rapid weight loss—can result in this alarming, clumpy hair loss, which tends to start a couple months after the event, Piliang says. The shedding can last for six months and may result in your losing up to 70% of your hair. But typically the hair grows back, she explains.

There are many more explanations for hair loss, including scalp infections, inflammatory diseases like alopecia areata, or systemic diseases like lupus. Treatments vary widely and may include a combination of oral or topical drugs, light therapy, dietary changes, and stress-reducing interventions. You really need an expert’s help to assemble all the puzzle pieces, says Dr. Laurel Schwartz, a dermatologist in private practice at the Philadelphia Institute of Dermatology.

If you’re experiencing skin irritation, redness, scaling or pain, Schwartz recommends seeing someone ASAP to head off risks like permanent hair loss and scarring.

More good advice: Stay away from “miracle” cures marketed online or in late-night TV infomercials. They’re not the answer. “Hair loss is such an emotionally charged experience,” Schwartz says. “And when you’re really upset, you’re willing to try anything.” Time spent experimenting with different over-the-counter or infomercial products is often time (and money) wasted.

Your hair can offer a glimpse of what’s going on in the rest of the body, Schwartz says. “If you notice a problem, discuss it with a doctor to determine the ultimate cause.”

TIME public health

You Asked: Why Do My Boobs Hurt?

You Asked: Why Do My Boobs Hurt?
Illustration by Peter Oumanski for TIME

Most of the time, blame hormones.

From a dull ache to a sharp stab, breasts hurt in a hundred different ways for a hundred different reasons. For many women, those myriad aches and stabs are the results of normal, healthy hormone fluctuations related to their menstrual cycles.

“Pain is most common during that period of a woman’s cycle just before she menstruates, when hormones like estrogen and progesterone peak,” says Karthik Ghosh, MD, director of the breast clinic at Mayo Clinic in Rochester, Minnesota.

You probably already knew that. But when your hormones go haywire, why do your breasts feel beat up? Rising estrogen levels stimulate the breasts’ milk ducts, while spiking progesterone does the same to a woman’s milk glands. Both can result in swelling and pain. Progesterone also causes fluid retention, which can lead to a feeling of heaviness or tenderness, Ghosh says.

With the onset of menstruation, levels of those hormones drop off, Ghosh says. For that reason, breast pain or tenderness tends to subside as soon as a woman starts her period. Because oral contraceptives iron out those hormonal peaks and valleys, women on birth control often don’t experience this monthly ebb and flow of aching. (But when women first start a contraceptive like the pill, some pain is common.)

Many women also experience cysts, which result when pockets of fluid form within the ducts of the breast. These cysts can sometimes be painful, says Dr. Susan Harvey, director of the Johns Hopkins Breast Imaging Section.

Young women in puberty, pregnant women and older women nearing menopause may all experience breast pain due to hormone fluctuations, says Dr. Bonmyong Lee, Harvey’s colleague and an assistant professor of radiology at Johns Hopkins. Particularly during the early stages of menopause, women who may have never had pain or cysts may suddenly start to experience both, Lee says.

Apart from these hormone-related issues, Ghosh says anything that causes chest wall muscle soreness—like starting a new workout—can cause what’s called secondary pain in the breasts. So can a common type of inflammation, called costochondritus, which affects the place where a woman’s ribs and sternum come together. Even an unsupportive brassiere can allow the breasts to pull on the chest wall, leading to pain, Ghosh says.

One condition that tends not to cause pain is cancer. For women who may notice a lump that is sensitive or painful, it’s more likely a benign cyst, Ghosh says. Still, she recommends seeing a doctor if you find a lump, painful or otherwise.

There are several less common or unproven causes of breast pain, from infection to caffeine consumption. So how can you determine whether to worry or brush it off? If the pain is concentrated in one part of your breast and doesn’t subside after a few weeks, see someone, Harvey says. You should also visit a doctor if your skin is flushed or red, which may be a sign of an infection.

“There’s no golden rule when it comes to identifying specific types of breast pain,” Ghosh says. “If it worries you or seems out of the ordinary, see a doctor.”

Read next: Should I Dry Brush My Skin?

 

TIME toxins

You Asked: Should I Dry Brush My Skin?

Illustration by Peter Oumanski for TIME

There may be benefits, but reducing cellulite isn’t one of them.

If you’re wondering what dry brushing is, the practice is exactly what it sounds like: Running a dry, soft-bristle brush over your bare skin. Methodologies vary, but most practitioners and beauty blogs recommend brushing your limbs and torso, always motioning toward your heart. Do this for a few minutes every day, they say, and you’ll increase blood flow and circulation, which will help your body and lymphatic system clear away toxins. Dry brushing is also thought to reduce cellulite and exfoliate, leaving your skin softer, more toned and better hydrated.

Unfortunately, there’s not much research to back up these health claims. “I know dry brushing is popular, but the actual benefits are unclear,” says Dr. Tina Alster, director of the Washington Institute of Dermatologic Laser Surgery and a clinical professor at Georgetown University.

Alster says that rubbing the skin—with a brush, your hand or anything else—will increase blood flow and circulation, giving your skin a flushed, youthful and “slightly swollen” appearance. (The same thing happens if you pinch your cheeks.) But your skin will return to normal very quickly after you’ve stopped brushing it, Alster says. There’s no evidence this temporary surge in blood flow will help your body remove waste or toxins, she adds.

Dry brushing will clear away dead skin cells. But exfoliating isn’t necessary for those in their teens and twenties. “When you’re young, your skin’s outermost layer will automatically turn over without any mechanical help,” Alster explains. Beginning in your thirties and increasing as you age, Alster says your skin’s cells can grow “stickier,” which can lead to accumulation and a dull appearance. “Exfoliation can help remove those stuck-together cells,” she says. “But you want to do it very gently and infrequently, or you may do more harm than good.”

Brushing too frequently or vigorously—or using a brush with rough bristles—could cause “micro-cuts” in your skin that may lead to infection, Alster says. Exfoliating more than once a week could also break down your skin’s protective barriers, leaving your hide less hydrated and prone to irritation, says Dr. Marc Glashofer, a New York-based dermatologist and member of the American Academy of Dermatology. For that reason, Glashofer says people with eczema or dry skin should avoid dry brushing altogether.

Glashofer mentions a common skin condition called keratosis pilaris (KP), which consists of many small rough bumps that tend to show up on the backs of arms and thighs. Dry brushing these areas could theoretically be beneficial, he says, but there’s no evidence yet.

And when it comes to reducing cellulite, both Glashofer and Alster say there’s nothing to back up such claims. “If brushing the skin twice per day would eliminate cellulite, you would have heard a lot more about it and there’d be some scientific proof,” Glashofer says.

Of course, not everything that benefits your body is easily captured by medical research. From meditation to massage, many practices once dismissed by clinicians have recently been linked to meaningful psychological and physical benefits. It’s possible dry brushing may one day fall into this category, but that day hasn’t arrived yet.

“If you like dry brushing and your skin looks good, that’s fine,” Alster says. “But would I encourage it as a dermatologist? Definitely not.”

Read next: 25 Delectable Detox Smoothies

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