Laser Hair Removal: Here's what you need to know before you take the big step

Something like, how much it hurts, where on your body it works and where it doesn't.

Read on for the rundown of laser hair removal procedures.

It works better on some areas than others.

If you're after a hairless bikini line or underarms, legs, or arms, you're in luck. "Those areas respond well to laser hair removal; a lot of it has to do with the combination of thinner skin and thicker hair," says Tina Alster, a dermatologist in Washington, D.C., who specializes in lasers. "Areas where the skin is thicker or hair is thin, like the back or chin, are harder to treat."

You need a large serving of patience and then some.

It usually takes three treatments spaced five to eight weeks apart to see results, but some people need six treatments to smooth an area. It's because lasers work by damaging stem cells in hair follicles, and it can take a few sessions to wipe out a single hair cell. "It slowly thins out hair," says Neil Sadick, a dermatologist in New York City, but the good news is you can shave in between.

Its not meant for everyone.

You can't use traditional hair-removal lasers on dark or olive-toned skin. Because they seek and destroy dark pigment, "it's incredibly dangerous and can burn and scar you," says Alster. "You've got to go to someone who has a Nd:YAG laser that's safe for dark skin." Other hair-removal lasers only work on fair skin with dark hair. "There's no laser that removes blonde hair," says Alster, adding that electrolysis isn't a valid alternative. "It's difficult to control an electrolysis needle, and people get scarring from it," she says. Wax, shave, or thread instead.

It has its periods.

It sounds counterintuitive, but start laser hair removal in the fall or winter, anytime except beach season. Just like lasers harm dark skin, "they're dangerous if you have a tan," says Alster.

It can be done in the comfort of your home.

Dermatologists like the Tria Hair Removal Laser 4X, which uses a diode laser and (just like professional lasers) only works on dark hair and fair skin. It's not nearly as strong as professional treatments, so it can take months to yield results, and it may never get rid of all of the hair in a given area, says Sadick. Skin in the armpits and along the bikini line typically gets smoothest the fastest, adds Sadick.

Avoid doing laser hair removals at a spa.

Unlike dermatologists, aestheticians may not spot a wart or skin infection that lasers can spread. Plus, if the laser hits a tattoo, "it can cause burning, and aestheticians don't always know to ask about sun exposure," says Alster. "I've seen people who had two laser hair-removal sessions that were fine, and then the third one burned like crazy because they'd been out in the sun."

Another reason to seek a dermatologist.

Another reason to get laser hair removal from a doctor, and a doctor only: You can use it on embarrassing, sensitive areas, like hair around the nipples. "It works really, really well there and on the stomach and chest," says Alster. You just can't have a belly-button piercing, or any other piercing, in, since metal conducts heat.

It is not a permanent fix for upper lip hair.

Sad, we know. But hormone levels shift with age, and as the balance of testosterone and estrogen changes, new hair will grow above your lip, says Alster.

Keep your razors close.

"You may or may not ever achieve total hairlessness," says Sadick. So expect to shave stray hairs. Just don't tweeze between sessions, lasers work by targeting dark pigment, and if you pluck a hair at the root, there's no pigment left to target.

It really, really hurts!

Its been said to feel like a rubber-band snap, if you heated up that rubber band first, and used the giant kind of rubber band that comes around newspapers. It tingles after, then smells a little like burning, but she says the stinging goes away quickly, faster than it does with waxing.

If you didn't know theses things, now you know. You just might want to think twice before taking the plunge!