Healthy Hair

Take care of your overall health. Hair is an ever-growing tissue affected by our physical well-being, says Elizabeth Cunnane Phillips, a trichologist at the Philip Kingsley Clinic in New York. (Trichologists specialize in hair and scalp health.) "Have you had a recent physical? How are you eating? Are you managing your stress, or is it managing you?" she says. Diet, particularly getting enough protein and iron, is vital to hair health. Stress can accelerate shedding, particularly in the shower. And a medical condition, such as a thyroid problem, could also cause hair issues.

Swim unprotected. What could possibly dampen a day at the beach or pool? Salt water or chlorine. Both can wreak havoc on hair, drying it out, causing split ends, and stripping color. Phillips recommends applying a strong leave-in conditioning treatment to damp hair before hitting the water

Protect your hair during the summer. And you thought sunburn was bad for your skin? Those rays are just as harmful to your hair, even though it won't turn red or start to peel. Rather, repeated sun exposure will leave your hair damaged and dry, while fading your dye-job. Cover up whenever possible, throwing on a wide-brimmed hat or wrapping a scarf around your mane. Opt for moisturizing shampoos and conditioners that protect against the two types of ultraviolet rays capable of causing sunburn, UVA and UVB, along with an SPF-fortified hair spray. Apply it to your hair whenever you'd wear sunscreen. At the end of summer, an intensive conditioning treatment at the salon could help rejuvenate frizzed-out locks.

Tie your pony tail too tightly. They're convenient and cute, yes, but they could lead to traction alopecia, or hair loss caused by styles that pull on your scalp. Instead of tying tightly, aim for loose braids, buns, and ponytails, and let your hair down before going to sleep at night. "It's important to get the right tie," Hammadi says. "Some are better than others. The thicker ones work well, and the ones that don't have a seam breaking up the middle. They're a little gentler on your hair." Even better: Try holding it back with a headband, instead. And if you must go the ponytail route, alternate the way you put it up—tie it low one day, high another, to the side the next—so you're not always stressing the same strands.

Tend to your scalp. "It's the bedrock for your hair follicles," Phillips says. "They're a millimeter and a quarter under the scalp. But most of us don't attend to it or even think about it." She recommends applying a weekly scalp mask, which exfoliates and moisturizers. These typically contain ingredients like aloe vera, and help minimize flaking while soothing the scalp. "It gives you a head of hair that you want to touch, that's luxurious and full of life," Phillips says.

Overdo the appliances. Even if they're pricier, invest in good tools. Make sure they offer different heat settings and, in the case of flat irons, display the temperature. Hair dryers should have a diffuser to help distribute heat more evenly. Still, it's best to let your hair dry naturally whenever possible. Blow-drying it can cause roughness, dryness, and loss of color, according to a 2011 study published in the Annals of Dermatology. Reserve dryers for special occasions, and keep the air cool. Beware flat irons, too: While they may make your hair look smooth and sleek, they can also turn it dry and brittle, leading to frizz and heavy-duty breakage. If you must use a flat iron, keep it on the coolest heat setting possible. And don't even consider turning it on until your hair is completely dry; otherwise, you'll end up with a lot of steam and damaged locks.

Overwash it. Shampooing and conditioning every other day will suffice, unless your tresses are extra oily. Washing too frequently causes dryness, Hammadi says. "If you constantly overwash, it's going to become too clean," he says. "Just like when you wash your clothes too much—they fade. It pulls out too many of your natural oils, so you won't have as much shine." This is particularly a concern if you've colored your hair; red and blonde tones are especially likely to fade if you shampoo too often. Note, however, that you don't need to wash with cold water: That's just a myth. Warm water works just fine.

Maintain it with regular trims. Parting ways with even half an inch can be excruciating if you're in pursuit of long, luscious locks. But it's necessary. Ideally, head to the salon every six to eight weeks, though you may be able to push it to 10 if you're trying to maintain length. Regular trims keep split ends from splitting more and more (and looking worse). Those with an intense styling routine—straightening or curling every day—typically need more frequent trims than those who sport a more natural look. One way to tell if it's time to call the salon: Inspect the bottom of your hair. If it doesn't come to a blunt end, you may be overdue.