No, sodium hydroxide is not usually an ingredient in hair gel. Sodium hydroxide, also known as lye, is a corrosive substance that can be harmful to the skin and hair if used incorrectly. It is commonly used in chemical hair relaxers, which are used to straighten curly or frizzy hair, but is not typically used in hair gels.

Hair gels typically contain ingredients like water, alcohol, and polymers that help hold hair in place. Common polymers used in hair gels include PVP (polyvinylpyrrolidone), PVP/VA (polyvinylpyrrolidone/vinyl acetate), and carbomer. These ingredients help create a flexible hold without damaging or drying out the hair.