The L'Oréal Professionnel Pro Fiber Restore Leave In Serum is designed to enhance and prolong the effects of the Pro Fiber Restore treatment. This leave-in serum helps to repair and revitalize damaged hair, leaving it feeling smoother, more supple, and looking healthier. It is ideal for use on medium to thick damaged hair, providing intensive care without weighing the hair down. Regular use can help to restore the hair's natural strength and vibrancy, making it easier to manage and style.