Hair colour fades for two reasons: the dye molecules wash out of the hair shaft, and the surrounding cuticle slowly opens and lets them go. A good post-colour routine slows both. There is no product on the market that genuinely prevents fading; there are several that meaningfully delay it.
What colouring does to the hair
Permanent colour works by lifting the outer cuticle layer of each hair, depositing pigment inside the cortex, and re-sealing. The chemical process (oxidative dye, often with a developer) inevitably weakens the cuticle and disrupts some of the disulphide bonds that give hair its structure.
The result is hair that is rougher to the touch, more porous, and more prone to losing colour from inside the shaft. Semi-permanent and demi-permanent colours are gentler but still create some porosity. Bleaching is the most disruptive of all because it removes pigment by breaking it apart.
The small set of adjustments that matter
Wash less often. Each wash slowly extracts colour, especially in the first two weeks after colouring. Aim for every two to three days where possible. Dry shampoo on intermediate days is a colour-saver, not just a convenience.
Cooler water. Hot water opens the cuticle, which releases colour faster. Lukewarm water for washing, a cool final rinse, is a free and effective adjustment.
Sulphate-free shampoo, mostly. Sulphates (SLS, SLES) are aggressive surfactants that strip colour. Gentler surfactants (cocamidopropyl betaine, sodium cocoyl isethionate) clean adequately without the colour cost. Use a sulphate shampoo once a fortnight to remove build-up; not as your daily.
Conditioner on every wash. Conditioners contain cationic ingredients (positively charged) that adhere to the slightly negatively charged colour-treated cuticle. They smooth the surface and seal it temporarily.
Weekly bond-building or protein treatment. Bond-builders (Olaplex, K18, similar branded systems) repair some of the disulphide bonds damaged by the colour process. Protein masks add small protein fragments that fill in cuticle damage. Used once a week, they extend the strength and look of coloured hair.
UV protection for hair in sunny climates. UV breaks down pigment in the cortex. Hats outdoors do most of the work; sprays with UV filters help for swims and beach days.
Pool chlorine and salt water
Both extract colour quickly, particularly from blonde and high-lift colours. Chlorine also reacts with metal residues in tap water (especially copper) and can shift blonde toward greenish tones. Two simple defences: wet hair with clean water before swimming (saturated hair absorbs less of the pool water), and rinse immediately after.
Heavy swimmers benefit from a weekly chelating shampoo, which binds and removes accumulated minerals. We have a separate article on hard water that covers this in detail.
Heat styling on coloured hair
Coloured hair is more porous and conducts heat differently than virgin hair. The damage threshold is lower. The rule of thumb: drop the iron or dryer temperature by 10 to 20 percent compared to what worked before colour, and always use a heat protectant. We have an article on heat damage specifically; everything in it applies double for coloured hair.
Colour is paint on top of architecture. Look after the architecture, and the paint stays longer.
Specific colour categories
Blonde and silver/grey. The most colour-vulnerable category. Purple or blue toning shampoo once a week corrects brassiness and yellowing; daily use can leave a violet cast. Bond-builders are particularly worthwhile.
Brunette and dark brown. Holds longer than blonde but fades to red-brown over weeks. Cool-toned glosses every six to eight weeks refresh the colour without a full re-dye.
Red and vivid fashion colours. The fastest-fading category, often visibly washed out within two weeks. Colour-depositing conditioners that match the shade add some pigment back with each wash and slow the rate.
What is not worth the money
"Colour-locking" sprays applied at the salon. Most are leave-in conditioners with marketing. The conditioners you use at home do the same job.
Expensive shampoos with the words "colour care" on the label and sulphates on the ingredient list. A cheap sulphate-free shampoo does more for colour than a premium sulphate one.
Anything claiming to "lock in" colour permanently. Hair is not a lock. Colour fades because of physical and chemical processes that no topical product can fully halt.
Key takeaways
- Colour fades because dye washes out and the cuticle opens; you can slow both.
- Wash less, cooler water, sulphate-free shampoo, conditioner every wash.
- A weekly bond-builder or protein treatment extends the look and feel of colour.
- UV, chlorine, and salt water all accelerate fading; defend against them when you can.
- Coloured hair tolerates less heat. Drop iron temperatures and always use a heat protectant.
Common questions
How soon can I wash after colouring?
Most colourists recommend waiting 48 to 72 hours. The cuticle re-seals during this window and the colour bonds more durably.
Are sulphates always bad for colour?
Strong sulphates strip colour faster than gentler surfactants. An occasional sulphate wash to remove product build-up is fine; daily use is hard on colour.
Do colour-depositing conditioners work?
They extend specific tones (purple for blonde, red for red, blue for brunette anti-brass) by adding a small amount of pigment with each wash. They do not replace a salon refresh but bridge the gap between appointments well.
What about hair masks?
A hydrating mask once a week supports the cuticle. A bond-builder or protein mask once a week supports the cortex. Alternate them, or pick the one your hair needs most.
Cura is informational and not a substitute for professional advice. Significant breakage, scalp irritation, or unexpected colour shifts warrant a conversation with your colourist or a dermatologist.