Yes, many hair growth shampoos are formulated to be suitable for all hair types, including colour-treated hair. However, it's crucial to choose a paraben-free shampoo that is free from harsh chemicals like sulphates, which can strip away colour and cause further damage to your hair. Always check the product label and look for shampoos that are specifically designed to be gentle on coloured hair while still promoting healthy hair growth and a stronger, more resilient hair structure.