I read that sodium hydroxide is one of the chemicals used for hair straightening, and it can burn the scalp if it comes in contact with it too long. I also noticed that sodium hydroxide is an ingredient in both my shampoo. Is this bad for my hair?
At the low concentrations, the sodium hydroxide should not hurt you or your hair (such as in shampoos)… but when you are using higher concentrations for straightening it, you must be careful.
Since they say hat sodium hydroxide can damage hair how often should we use a hair staightner and what tpye of hair does it damage?