The Serum has a liquid texture: do not apply more than one pump at a time, and section hair beforehand if necessary. Shake before use. To complete the Spectrum Vitamino Color Spectrum, apply to clean, towel-dried hair. 1-2 pumps for fine to medium hair, 3-4 pumps for thicker hair. Distribute evenly over lengths and ends. Do not rinse. Dry hair completely, using the desired drying techniques. Once hair is dry, straighten with a straightening iron. Designed for use with a straightening iron. For best results, use with Steampod. Shake before use. Store in a cool, dry place. Clean and lock pump after each use. In case of contact with eyes, rinse thoroughly with water. The evolution of parfum over time is expected due to the potent nature of the ingredients, it is important to note that this change does not affect its efficacy.