Acidic vs. Alkaline Hair Colour: What’s the Difference?

Let’s talk about the science of hair colour. Often, we put the focus on the finish and performance it offers. Does it enhance shine? How long will it last? What does the shade look like as it fades? But the acidity and alkalinity of hair colour is just as crucial a point to consider – perhaps not to your client, but certainly to you, as the colourist who helps them reach their perfect hue. 

So what exactly is the difference between alkaline and acidic oxidative hair colour? In this article, we break down how the pH of a formula affects the results you achieve in the salon. Plus, we reveal the ideal pH level for your client’s desired look, so you can choose their perfect colour product with ease. Here’s everything you need to know…

Woman with long, brown glossy hair smiling at the camer.
Side profile of woman with long, glossy, ash brown hair, creating using Wella Shinefinity.
Hand holding tube of Wella Shinefinity Glaze.
Woman with glossy, caramel blonde, curly hair smiles at the camera, created using Wella Shinefinity.
Back of woman’s head showing before and after of Wella Shinefinity glaze on blonde hair.
Back of woman’s head showing before and after of Wella Shinefinity glaze on brown hair.
Close-up of hair colour on foil, being picked up with a tint brush.
Side profile of woman as colour is applied to her hair with a comb.