Forbes reported, as you might expect, this is not a standard hair dye that changes your current shade to a single different one, but once it is on hair, repeatedly changes from one color to another based on the surrounding environment. It is based on thermochromic ink formulated to be safe for the scalp.
When cold, dyed hair appears dark and the hotter it gets, the lighter and more vibrant it becomes. Variations include black to red, black to white, silver to powder blue, blue to white and black to yellow. It is a semi-permanent color that lasts for a few washes and reportedly does not damage hair more than other semi-permanent dyes.
Bowker explained, in the Forbes report, “These chemicals that would normally be irritants on their own can be prevented from causing a negative effect with a process called ‘polymeric stabilization’, in which chain-like molecules (polymers) wrap around the irritant." The resulting dye will then change color in response to a stimulant.
Bowker added that above a certain temperature, one of the molecule forms is more stable than the other, so a reaction takes place producing a molecule with a slightly different absorption of light, and thus a different color. The product is not yet commercially available, but is anticipated to reach shelves by the end of 2017.