KÉrastase Resistance Fibre Architecte is an icon in the making. Specially formulated for brittle hair with extremely damaged lengths & split ends, this reparative serum is the perfect way to finish your look & add a healthy, long lasting shine. The weightless formula of KÉrastase Resistance Fibre Architecte seals & repairs damaged hair so you can enjoy beautifully smooth hair & shine, with renewed health & vitality. Simply pump the dual product in to your hands & mix, apply evenly to the mid-lengths & ends of dry hair. Perfect to use prior to heat styling to protect & repair.