Who They're Good For: Those with fine or thinning hair.
Who Should Avoid Them: Anyone whose hair is very dry or damaged.
What They Are: Most salons offer Great Lengths extensions. Each one comes as a 100-strand lock of human hair secured at the top with a keratin protein polymer cap. In the salon, each cap is bonded to your own hair, near your scalp, with a tonglike tool. Depending on the length and thickness of your hair, you'll need 50 to 100 pieces.
How Long the Process Takes: Two to four hours.
Maintenance: "Shampoo and condition with silicone-free products, because silicone can make extensions slip off," says hairstylist Ryan Trygstad, at Sally Hershberger Downtown in New York City. Deep-condition the ends, but avoid getting conditioner on the bonds. Also, extensions tangle easily; brush them gently at least twice a day with a boar-bristle paddle brush. You might want to schedule a two-month follow-up appointment so your stylist can replace any extensions that have fallen out.
How Long They Last: Four months (at which point it'll be easy to see where the extensions are attached to your real hair). Your stylist will use an alcohol-based solution to dissolve the bonds and then gently pull off each extension.
Price: $1,500 to $2,600 (depending on volume of natural hair).
Coming Soon! Great Lengths has created the Multi-Sonic method, which will allow stylists to attach five 100-strand locks at once, cutting the total process time in half. The system should be available in Great Lengths–certified salons by midyear.
Next: You should avoid a weave if...
Who They're Good For: A partial weave is best for a woman who wants to add volume or length to her current style and has textured hair (such as African-American women who haven't used relaxers). A full weave is a solution for someone who wants to completely change her texture or color.
Who Should Avoid Them: Anyone who washes her hair more than once a week (washing loosens the weave). A partial weave won't look natural on women who have baby-fine or flat hair.
What They Are: For a partial weave, a stylist makes several small, tight braids along your scalp, then uses a curved needle and cotton, nylon, or silk thread to secure a weft (a line of extensions that are machine-stitched at the top, like a curtain of hair) to the braid. For a full weave, all your hair is pulled into braids before the wefts are sewn on.
How Long the Process Takes: A partial weave can take as little as an hour and a half; a full weave can take three to four hours.
Maintenance: Shampoo and condition every three weeks. Dry braids completely to avoid scalp irritation.
How Long They Last: Every four weeks, your stylist tightens the braids and the weave; every three months, she will remove the wefts, wash and condition them, then reattach them. The hair should last up to a year.
Price: $200 to $2,000 (depending on the length and type of hair).
Next: Hair clip-ins are great for...
Who They're Good For: Someone who wants longer or thicker hair temporarily.
Who Should Avoid Them: Anyone with fine hair that can't hide the clips.
What They Are: Clip-in extensions range from a one-inch piece with one clip to a weft that runs from ear to ear with three to five clips. They're made with human or synthetic hair and come wavy or straight and in a wide range of shades. Clip them underneath the top layer of your hair to conceal the attachment.
How Long the Process Takes: Five to ten minutes.
Maintenance: You can shampoo and restyle them.
How Long They Last: EClip in and remove as often as you like (but don't shower or sleep with them in). Quality extensions can be reused forever.
Price: At a salon, you'll pay $500 to $1,000 for eight pieces (which includes a consultation, fitting, and lesson on attaching them). Some salons offer rentals: At Warren-Tricomi Salons in New York City, you can rent clip-in extensions for a day for $100. Or you can buy them and put them in yourself; two popular, natural-looking options are HairDo 5 Piece Clip-In Ultra Invisible 16 Extensions ($49; QVC.com ) and Ted Gibson Clip-In Extension Systems ($150; ShopNBC.com ), which are made of a new protein-based synthetic hair that can withstand hot rollers, a curling iron, or a straightener.
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