Shower gels are known to consist of the same basic ingredients as soap - water, betaines, and sodium laureth sulfate, or SLS. But the main difference between the two products lie in its surfactants - compounds known to lower the surface tension between substances, which helps in the emulsification and the washing away of oily dirt. The surfactants of shower gels do not come from saponification, that is by reacting a type of oil or fat with lye. Instead, it uses synthetic detergents for surfactants derived from either plant-based sources or petroleum. This gives the product a lower pH value than soap and might also feel less drying to the skin. Some people have likened the effect to feeling less "squeaky clean", however.