The duration of a keratin treatment on curly hair can vary depending on factors such as hair type, texture, and maintenance routine. On average, a keratin treatment can last anywhere from 3 to 6 months with proper care and maintenance. To prolong the results of your keratin treatment, use sulfate-free shampoos and conditioners, avoid excessive heat styling, and touch up any regrowth or new growth as needed. Additionally, consider using keratin-infused styling products to maintain smoothness and manageability between treatments.