Kerastase Bain Nutri Thermique Shampoo hair is easier to untangle Deep Nutrition. An exclusive complex of nourishing agents operates in the most sensitised areas of the fibre, offering intense nutrition to the hair. Heat Activation. Heat activates the thermo-reactive formula, trapping the nourishing elements deep inside the hair fibre. Thermic Protection. The heat-activated formula creates a protective film all around the fibre to help prevent dryness.