What is the main ingredient in most hair color formulations?

The main ingredient in most hair color formulations is ammonia. Ammonia plays a crucial role in hair coloring because it acts as an alkaline agent that helps to open the hair cuticle, allowing the color to penetrate the hair shaft effectively. By raising the hair's pH level, ammonia allows the dye molecules to enter the inner structure of the hair, which is necessary for long-lasting color.

Hydrogen peroxide, while important in the hair coloring process as a developer and for its role in oxidation, is not the primary ingredient responsible for opening the hair cuticle. Alcohol and esters are not typically foundational components of hair color formulations; rather, they might be used in smaller quantities for specific purposes, such as conditioning or solvent properties.