Depending on the hair type, repeated use of hair straighteners, like most other heat styling tools, can cause varying amounts of damage such as split ends, thinning of the hair shaft and even causing hair to become brittle and prone to breakage. Generally, after extensive damage, hair will show signs of dryness and display an unhealthy appearance. However, many companies, such as L’Oréal and Tresemmé, have began to manufacture heat protection sprays and cream which aim to reduce the amount of damage that is caused by the use of straighteners.