Olaplex Number 3 Hair Perfector (100ml or 250ml) is a deep treatment that reconnects bonds in the hair that have been broken by colouring, lightening or excessive heat styling. By multiplying and rebuilding the hair's bonds, it eliminates breakage whilst making colour last much longer. This results in healthy hair that is revitalised with a new lease of life. You'll see the best results when you use this in conjunction with step 1 + 2, which are in-salon services. Silicone, Sulphate, Phthalates, DEA and Aldehyde free plus it is not tested on animals. Vegan-friendly. Directions of use: Apply a generous amount to wet (not washed with shampoo) hair then comb through. Leave in for 10 minutes or longer. Rinse and wash with a Sulphate free shampoo then condition. If necessary, can be used more than once per week.