1. Wash the hair twice with a clarifying shampoo, rinse, and towel dry.

2. Blow-dry the hair straight on medium heat until completely dry. Brush the hair thoroughly.

3. Divide the hair into thin sections using hair clips.

4. Apply keratin with a brush 1 cm from the roots (do not apply directly to the scalp), then comb the hair with a fine-tooth comb to distribute the keratin evenly and remove any excess product.

5. After 20 minutes, blow-dry the hair until it is completely dry.

6. Use a ceramic flat iron to straighten the hair. For fine hair, set the temperature to 185˚C; for medium hair, 200˚C; and for thick hair, 220˚C. For perfect results, repeat 5 to 10 times.

7. After 3 days, wash the hair, preferably with a sulfate-free shampoo to prolong the keratin effect. (If the hair gets wet or wavy during the 3 days, blow-dry it and straighten it with a flat iron.)