Sulfate-free products might not create as much lather in the shower, but that frothy bubble that comes from sulfates in your shampoos, can cause problems. The problem is that they clean a little too well. The scalp produces natural oils that nourish hair, and sulfates wipe out those natural oils. If your hair is too oily, small amounts of sulfates can be good, but if hair is dry, sulfates can be irritating to the scalp. Most hair extensions are made of 100% human hair and aren’t attached directly to your scalp, so they don’t receive the natural oils from your hair as they naturally should. Sulfates will dry out extensions and strip them of their color. Also if you have keratin bonds (most fusion bonds are made of of this) sulfates WILL break down the keratin weakening it and become sticky which will cause matting or the hair extensions to shed or completely fall out.
What to look for on the packaging:
Sodium laureth sulfate, ammonium laureth sulfate, and myreth sulfate are some technical names of sulfates.