Hair extensions are pieces of synthetic or human hair that are bonded to your natural hair. Human hair is cut from a woman, child's or man's head and is safe to straighten, while synthetic hair is made up of artificially spun fibers, specifically plastic, nylon and polyester. Such extensions must never come in contact with direct heat, unless they are made with special heat-resistant synthetic hair. Know the differences between human hair and heat-resistant synthetic hair to get the look you want without damaging your new locks.

Human-Hair Extensions

Step 1

Brush through hair extensions with a special hair-extensions brush (looper brush), which won't pull or tangle hair. You can buy a looper brush at a pharmacy or a salon store.

Step 2

Spray extensions thoroughly with a heat-protectant thermal styling spray. Heat protectants protect hair from the damage caused by daily use of hot tools, like straighteners.

Step 3

Turn on your straightener to give it time to heat up. If your extensions are clip-on, place the end of the extensions underneath a heavy object at the edge of a counter or table so that the extensions hang free. If they are braided-, sewed- or glued-in extensions, they should be styled while on the head.

Step 4

Clamp the straightener over the hair and pull through as you would with your natural hair. The heat of the straightener will straighten the hair. Run the straightener over numerous times depending on how straight you want the extensions.

Step 5

Apply hairspray for a longer lasting style. The style will last many hours unless washed or subjected to harsh weather conditions (wind or rain).

Heat-Resistant Synthetic Hair Extensions

Step 1

Brush through synthetic hair with a looper brush.

Step 2

Spray extensions thoroughly with a heat-protectant thermal styling spray.

Step 3

Straighten hair with a straightener that has a digital temperature gauge. Typically, synthetic hair cannot withstand heat over 180 degrees, so a high setting will not be safe for synthetic hair. To be absolutely certain of the temperature that your synthetic hair can withstand, read the instructions or call the company that makes your extensions.

Step 4

Apply a special wig hairspray to hold the style. Wig hairspray is safe for synthetic hair and can be found at your local salon store or pharmacy.