Grant Cornett/Time Inc. Digital Studio
FALSE. "Hair grows from the roots, not the tips," says Michael Wright, senior research scientist at Nexxus Salon Hair Care. A trim removes split ends to prevent them from moving farther up the hair shaft, saving you from having to cut more to eliminate the damage. Keep your hair healthy in the first place with conditioning treatments and sun and heat protectors, says Saurabh Desai, principal scientist at Aveeno Nourish+.
2. True or False? Brushing Your Hair Often Makes It Healthier
FALSE. Brushing your hair 100 times before bed won't make your hair look any better. In fact, it might make it look worse. "Over-brushing can dull hair by destroying the cuticle, as well as causing split ends and breakage," says Desai. And using the wrong tool could further harm hair. In general, plastic and metal bristles can weaken the hair cuticle and cause damage or static and flyaways, so consider switching to a gentle brush with natural boar bristles. "Stick to just enough brushing to keep your hair from becoming tangled -- the brush should be able to move through the hair with ease," says N.Y.C. celebrity hairstylist Miok. For some, that might mean as little as a few strokes just once or twice a day.
3. True or False? Massaging Your Scalp Stimulates Hair Growth
FALSE. "Scalp massage can increase blood circulation, decrease stress and help distribute the scalp's natural oils onto the hair," says Desai. "All of this may lead to better functioning of the cells that are creating hair follicles, so your hair grows at its optimal rate -- however, that rate will not increase." On average, hair grows a half inch every month.
4. True or False? Chemical Straighteners Change Your Texture Permanently
FALSE. "As hair grows, your natural texture returns," says celebrity hairstylist Serge Normant at N.Y.C.'s John Frieda Salon. After a straightening treatment, the visible hair will be permanently altered, but the chemical process can't penetrate your roots. Likewise, daily blowout devotees might think they've unkinked their curls for good because hair starts to seem straighter over time, but what they're actually seeing is damaged hair that has lost texture, not a permanent change.
5. True or False? Wearing a Ponytail in the Same Area Can Give You a Bald Spot
TRUE. "The effect is called traction alopecia. The constant tugging by a tight band can scar hair follicles and cause them to stop growing new hair," says Doris Day, a dermatologist in N.Y.C. She suggests switching pony positions daily to alleviate tension. Tie back hair with a soft elastic band and wrap the ponytail as loosely as possible, suggests Desai. It's not just ponytails that can be the culprit, either -- headbands, braids and barrettes may result in similar damage when repeatedly worn in the same spot.
6. True or False? A Cold Rinse Adds Shine and Tames Frizz
TRUE. A blast of cold water at the end of your shower can make hair appear shinier because it temporarily helps the cuticle flatten down onto the hair shaft, explains Desai. But the results might not last if you don't properly dry your hair. Make sure the cuticle remains flat by applying a deep conditioner or silicone-based product to seal it.
7. True or False? Hair Can Become Immune to Shampoo
FALSE. Shampoo will always do its job: clean. So why does it seem like your favorite bottle suddenly stops working? "Shampoo contains ingredients that condition and provide styling benefits, but it can also leave a residue that builds up," says Desai. If you start to notice dullness, use a clarifying shampoo (try Nexxus Aloe Rid Gentle clarifying shampoo, $11; at drugstores) once or twice a month to remove accumulated product -- any more often and you could strip hair of its healthy natural oils.
8. True or False? Coloring Can Change Your Hair's Texture
TRUE. Temporarily, of course -- but sometimes for the better. Permanent color removes the protective layer on your hair and lifts the cuticles so dyes are able to penetrate, says Desai, while semipermanent dye deposits color onto hair and is less harsh. Both methods have benefits, says N.Y.C. trichologist David H. Kingsley: "Color can swell the hair shaft and give it body." The change is especially noticeable on women with fine or thinning hair, as well as those with gray roots.
It's Your Call ... Is Coloring Hair During Pregnancy Dangerous?
Check with your doctor first, especially if you have allergies, but "it's probably not harmful. However, you should wait until the second half of your pregnancy when the baby is fully formed," says Eileen Krim of Northern Obstetrics and Gynecology in North Hills, N.Y. Can't go another second without a color fix? Krim recommends highlights "because they start a quarter inch from the scalp, where the dye isn't being absorbed into the body." If you're getting your hair professionally colored, "schedule the appointment for when the salon is less crowded," she says. "Definitely stay away from peak hours on Saturday afternoon to avoid inhaling fumes." If you choose to color at home, wait until the third trimester. "Work in a well-ventilated area and wear gloves," Krim says. Look for dyes that have low or no ammonia, and don't assume that "natural" dyes are chemical-free -- often these contain the same compounds found in regular hair color.
-- Alonna Friedman
Also on InStyle.com