Colour-safe haircare: how to keep salon colour from fading fast

Sulphates are strong detergents that create a rich lather and clean effectively, but they also open the hair cuticle wider than gentler cleansers, which lets colour molecules wash out faster with every shampoo. Sulphate-free formulas clean with milder surfactants that still remove oil and product buildup but close the cuticle more quickly after washing, which is why they're the default recommendation for any freshly coloured or chemically treated hair.

Hair's cuticle sits open at a slightly higher pH and closes tightly at a slightly acidic pH, roughly 4.5-5.5, which is where healthy, undamaged hair naturally sits. Colour services and even tap water push hair toward a more alkaline pH temporarily, so pH-balanced shampoos and a cool-water final rinse both help close the cuticle back down after washing and processing, trapping colour pigment inside the strand rather than letting it wash out through open cuticle layers.

Heat styling is one of the fastest ways to fade colour, both because heat speeds up pigment breakdown and because it dries out the hair shaft, making the cuticle rougher and more prone to letting colour escape with each wash. A heat protectant spray or serum applied before blow-drying, straightening or curling isn't optional for coloured hair — it forms a barrier that reduces direct heat damage to both the colour and the hair's internal structure.

Pigmented, colour-depositing masks and glosses (including purple or blue shampoos for blonde and grey hair, which neutralise brassy yellow and orange tones) work by refreshing pigment between salon visits rather than replacing the original colour service. Used once or twice a week, they extend the vividness of the base colour and buy time between appointments; used more often, they can build up and shift tone more than intended, so following the product's stated frequency matters more than with a regular shampoo. Washing less often overall — every 2-3 days rather than daily, with a dry shampoo in between if needed — remains the single biggest factor in colour longevity, since simply reducing water and surfactant contact slows fading more than any single product.