Abstract: A method of treating hair to reduce frizz involving the following steps: (i) prewashing the hair with water, (ii) applying a frizz reducing product to the hair using at least one of a brush and a spray, (iii) drying the hair in air, (iv) rinsing the hair with water, (v) drying the hair, (vi) applying to the hair a flat iron, and (vii) rinsing the hair with water. The frizz reducing agent used to treat hair is glyoxylic acid. The specific temperature the flat iron is set will depend on the specific hair type and degree of frizz.