Via: The Science Of Black Hair Author: Audrey Davis-Sivasothy
There may be times when oils and oil-based moisturizers are preferable to water-based moisturizers for maintaining hair in a particular style. For example, for naturals who press or straighten their hair, or anyone who sets their hair, water based moisturizers will always cause the hair to revert. The high water content of water-based moisturizers breaks and reestablishes the hydrogen bonds that pressing and setting temporarily reorganizes or eliminates. A moisturizer with a higher synthetic oil or silicone content will better seal the hair against intrusion from external moisture and humidity in the surrounding air. While typically not as moisturizing as water-based products, oil-based products will resist introducing more moisture into the strands and serve as a barrier as well.