What is the most common volume of developer used in hair color?

The most common volume of developer used in hair color is 20 volume. This is because 20 volume developer is ideal for standard coloring processes, as it lifts the hair color by one to two levels while also providing the necessary strength to activate the color without causing excessive damage. It contains hydrogen peroxide at a concentration that is effective for most hair types and is versatile enough for both permanent color applications and achieving gray coverage.

Higher volumes, such as 30 and 40, are used for more significant lifts and specific techniques like high-lift coloring or for lighter shades, but they can lead to more damage because of the stronger oxidative effect. Conversely, 10 volume is typically used for deposit-only applications or for very subtle lifting, making it less common for general coloring needs compared to 20 volume. This balance of effectiveness and gentleness makes 20 volume the most frequently used developer in hair coloring.