L'Oréal has developed a novel hair dye formula that works just as well as traditional hair dye, but without the ammonia odor associated with those formulas. New INOA (Innovation No Ammonia) relies on a chemical called monoethanolamine, or MEA, which has no odor.

MEA is alkaline (as opposed to acidic), like ammonia, so it can accomplish the first step in permanent hair dye, which is to open the hair's cuticles. In fact, L’Oréal already sells ammonia-free permanent hair dyes that contain MEA in the U.S. and Europe. But because MEA does not open the cuticle as efficiently as ammonia, it does not allow the hair coloring ingredients to penetrate the hair strands as well. For this reason, MEA-based permanent hair coloring was only being used to darken the hair one shade, and not to lighten hair or color gray. So the L’Oréal chemists gave MEA a boost.

INOA contains oleogel, which is mixed together with MEA and the other key components for tinting locks—the oxidative hair dye and the hydrogen peroxide that develops the hair dye. Oleogel contains special emulsifying agents that allow the oil to mix with the other water-based ingredients. But, when the mixture is on hair, the oil coats the outside of hair strands and repulses the MEA, driving it to open the cuticle and penetrate the hair. Adding oil changes the ability of MEA to penetrate the hair.

INOA is already available in Europe, but consumers in the United States and Canada should be able to try the new hair coloring within the first three months of 2010, according Pamela Alabaster, senior vice president for corporate communications & external affairs for L’Oréal USA.

Moreover, the product should eventually be available for home use as well. L’Oréal plans to sell INOA to salons at a 20% premium compared to its current professional brand, Majirel, although it is not clear how much more consumers will pay to be part of the new "revolution" in hair coloring.