Leave-in conditioners are applied following towel drying of the hair and are designed to remain on the hair shaft to aid in styling. They are removed with the next shampooing. A large category of leave-in conditioners, known as blow-drying lotions, are designed to coat the hair shaft and protect the hair protein from heat damage during the drying process.
The most popular leave-in hair conditioners are designed for persons with curly or kinky hair. These products lubricate and moisturize the hair shaft while aiding in styling. For example, oil sheen sprays and oily pomades help retain water within chemically straightened hair shafts and decrease the combing friction between hair shafts thereby preventing hair breakage. For persons with fine, straight hair, the oily leave-in conditioner would render the hair limp and hard to style, but for persons with coarse kinky hair, the oils improve manageability and impart shine. These products typically contain petrolatum, mineral oil, vegetable oils, and silicone and function as a true hair moisturizer.
Leave-in conditioners can create a film over the hair shaft that may be difficult to remove with shampooing. For individuals with tightly kinked hair, this is advantageous because it allows more frequent shampooing with less hair damage. Certainly for persons with fine, straight hair, this conditioner build-up would create the appearance of greasy, unclean hair. It is important to remember that the main purpose of a shampoo is to clean the scalp, not the hair. The amount and type of leave-in conditioner applied depends on degree of curl present in the hair shaft, tightly curled kinky hair requires more conditioning than straight hair.
