Does Permanent Hair Dye Fade? How Long It Lasts and Why
Yes, permanent hair dye fades. Washing and light are the two measured causes, and in the lab study that separated them, colour changed most when both acted together. No study we found puts a number of weeks on that fade; the measured drivers are washing and light, not time. Where you see "six to eight weeks", it fits the re-colour cycle, not a measured fade: scalp hair grows about 0.27 to 0.43 mm a day, so six weeks gives roughly 1 to 2 cm of regrowth whether or not the lengths have faded.
Key points
- It fades, but it isn't shown to wash out the way semi-permanent does. The colour is built inside the hair; the lab studies measured partial colour change, not wash-out.
- Two measured causes: washing and light, worst together.
- Who sees it most: colour on lightened or natural white hair changed much more than on brown hair. Red is the shade family the research flags.
- What follows from the evidence: fewer washes and less light exposure; one industry lab test favours certain conditioning polymers. Most other tips are untested on permanent colour (the full list).
At a glance: what fades permanent colour
| Factor | What has been measured | What hasn't |
|---|---|---|
| Light + washing | Greatest colour change together; significantly smaller for either alone (auburn dyes) | Weeks or washes to visible fade in normal wear |
| Hair type | Natural white and bleached hair change much more than brown | How much more, why, and whether mixed grey behaves the same |
| Shade | Red-dyed hair (dye type not stated) fades under UVA; one application allows red a looser limit | Any independent ranking of shade families; brown, blonde, ash or black data |
| Shampoo pH | Alkaline shampoo faded a direct dye more | The effect on permanent colour; acidic aftercare; sulphate-free shampoo |
| Chlorine, heat, first wash | None found | Whether pool water, heat styling, time before the first wash or hot rinsing fade permanent colour |
Does permanent hair dye fade?
Yes, permanent hair dye fades, even though the colour is formed inside the hair. In laboratory tests on commercial permanent auburn dyes, both light exposure and shampooing changed the colour, and the two together changed it significantly more than either alone. Being built inside the hair does not make it wash-proof.
Permanent colour goes into the hair unfinished. Oxidative colour starts as small, colourless precursors that only become coloured once they react together inside the hair, after an alkalising agent, usually ammonia, has opened the cuticle (the UK trade body, the CTPA, and da França et al., 2015, describe it this way). Semi-permanent colour goes in already coloured and is not bound to the hair, so it washes out gradually.
The study that separated the causes, Locke and Jachowicz (2005), found that "the extent of fading, as measured by the total color change parameter, dE, is greatest for colored hair subjected to both irradiation and shampooing, and significantly smaller for hair undergoing only irradiation or washing." ΔE (written dE in that paper) is the instrument measure of how far a colour has moved. It records the visible change on the hair, not the amount of dye lost.
Zhou and colleagues (2009) start from the premise that wash fade is dye dissolving in water. No published source describes the route formed dye takes out of the fibre, or links fade rate to dye molecule size. Every fade study that names its shade tested red or auburn; there is no published fade data for brown, blonde, ash or black permanent shades.
How long does permanent hair dye last?
Until regrowth shows, in practice; the lengths fade at a rate driven by washing, light and hair type. No published source gives a figure in weeks, or in ordinary washes, for permanent colour fading in normal wear. The figures that exist are laboratory wash counts and one patent application's claimed limits after 20 washes. How often a client washes, and how much light her hair gets, will tell you more than any calendar.
Regrowth is the part you can put numbers on. In a study of 2,249 adults aged 18 to 35 across 24 ethnic groups, average scalp hair growth ran from about 0.27 to 0.43 mm a day (Loussouarn et al., 2016; all six authors worked for L'Oréal). That gives this much new, uncoloured root:
| Time since colouring | Regrowth (0.27 to 0.43 mm a day) |
|---|---|
| 4 weeks | about 8 to 12 mm |
| 6 weeks | about 11 to 18 mm |
| 8 weeks | about 15 to 24 mm |
Those are group averages for adults under 36, so an individual client, especially an older one, can sit outside them. Where regrowth contrasts with the target, such as white regrowth under a dark shade, a centimetre of root can show before the lengths have visibly faded. That is why the re-colour interval and the fade rate are different questions. For the root itself, see root touch-ups with Life Color Plus.
The closest anchors come from the Locke and Jachowicz study. Its fastest-fading formulations reached a ΔE of roughly 4 to 6 after ten shampoos. With 32 hours of light in a weatherometer (a cabinet that simulates sunlight) added, just four shampoos brought them to roughly 14 to 16. None of these sources says how large a ΔE a client would notice, so read the numbers as relative, not as visible or invisible. Different protocols, cabinet hours rather than days outdoors, and the study's worst-performing dyes: treat it as direction, not a timeline. The direction is that light adds substantially to washing.
One published patent application (Pratt, US 2002/0124329) claims a maximum fade after 20 washes under its own test: ΔE 2.5 for blonde, light brown, dark brown and black, and 5.0 for red.
A 20-wash figure does exist, but it is for demi-permanent colour: da França et al. (2015) describe demi as having "resistance up to 20 washes". There is no published equivalent for permanent colour. For how the two categories differ in the bowl, see mixing permanent and demi colour in the same bowl.
Will my hair go back to normal after permanent dye?
Not exactly. Permanent colour lifts some of the hair's own pigment as it develops, and nothing suggests that change reverses as the colour fades. Permanent colour's ammonia, working with the developer, lifts some of the hair's own melanin. In demi-permanent colour, the milder alkaliser, monoethanolamine, "does not oxidize the melanin" (da França et al., 2015).
Exactly what shade is left after fading hasn't been measured: no study counts the artificial dye left in the fibre once fade is visible. For what lightened hair contains once natural pigment has been lifted, see underlying pigment explained.
Why is my hair not holding permanent colour?
Hair type matters: in the one study that compared hair types, colour on natural white hair and on bleached hair changed much more than colour on brown hair. The result came from auburn dyes. These two hair types are the documented higher-change cases, so they are the clients to brief before you start.
No study explains why. One untested possibility: ΔE records visible change, and white or bleached hair has no darker base to mask lost dye, so the same loss may show more. Porosity is often blamed, but no fade study tests it, and mixed grey heads were not tested.
The fade studies did not test processing time or developer strength, so they can't rule out under-processing behind a fast fade. Check your mix and timing against the manufacturer's instructions first; see Life Color Plus mixing ratios in practice.
Tell lightened and white-haired clients at consultation that their colour is likely to show more change than it would on a brown base. For full coverage on white hair, see the grey coverage formula.
Why is my hair colour fading after 2 weeks?
No study ties permanent-colour fade to a two-week timescale. The documented causes are washing and light, so a client who washes often and spends time in the sun will see change sooner. Which shampoo surfactant strips permanent colour fastest has not been reported: one study varied it, but its published summary gives no result. No study tests whether acidic aftercare slows it.
On washing, Zhou and colleagues found positively charged (cationic), water-repelling polymers worked best at stopping dye dissolving out. Their lead polymer, Polyquaternium-55, gave "up to 50% color protection" when used in a full colour-protection regimen. The lead author worked for an ingredient supplier, International Specialty Products.
On pH, one independent study, Yun and Ahn (2023), found that an alkaline shampoo (pH 7.80) caused significantly more colour change than shampoos at pH 5.10 or 6.44. That study tested a direct dye, not permanent colour, and found the dye mattered more than the shampoo. For permanent colour, the effect of pH has not been reported: Zhou and colleagues tested it, but their summary gives no result.
On light, UV filters applied to the hair at 30 mg per gram absorbed under 25% of UV (octyl methoxycinnamate) and about 40% (benzophenone-3 and -4) in the Locke and Jachowicz calculations. So even the better filters let most of the UV through.
So tell the client: wash less often, consider aftercare with a cationic conditioning polymer (the type that did best in the one lab test), and cover hair in strong sun. Don't promise that acidic aftercare or sulphate-free shampoo will hold permanent colour; neither has been tested on it.
How to make permanent hair colour last longer: what's tested
Two tips follow directly from the measured causes, one rests on partial evidence, and the rest are untested on permanent colour. Colour-care tips are often listed side by side. Ranked by the evidence:
- Measured cause Wash less often. Washing is one of the two measured causes of fade (Locke and Jachowicz, 2005). Count a swim as a wash: one patent application defines washing to include it, though pool fade itself is unmeasured.
- Measured cause Cover hair in strong sun. Light is the other measured cause, and light plus washing faded colour most. No study tested hats or cover, but filters alone are weak: in Locke and Jachowicz's calculations the best single UV filters absorbed only about 40% of UV at 30 mg per gram of hair.
- Partial evidence Use aftercare containing a cationic, water-repelling polymer. In an industry-authored lab test on permanent dye, polymers that were both positively charged and hydrophobically modified worked best; the lead one (Polyquaternium-55) gave "up to 50% color protection" as part of a full regimen (Zhou et al., 2009). The lead author worked for an ingredient supplier, International Specialty Products.
- Not tested on permanent colour Choose a lower-pH shampoo. An alkaline shampoo (pH 7.80) faded colour more than pH 5.10 or 6.44 shampoos, but that was a direct dye, not permanent colour, and the dye itself mattered more than the shampoo (Yun and Ahn, 2023).
- Not tested on permanent colour Sulphate-free shampoo. One study varied shampoo surfactant on permanent dye but its summary reports no result. It may help; no study we found shows it does.
- Not tested on permanent colour Rinse with cool water. No study we found tests water temperature.
- Not tested on permanent colour Wait 48 hours before the first wash. No study we found tests time before the first wash.
- Not tested on permanent colour Heat protectant before styling. No study we found measures heat styling fading permanent colour. Protect hair for other reasons, but don't sell it as colour protection.
- No independent test Antioxidant or "colour-seal" products. One manufacturer-authored study reported better colour longevity with its own antioxidant (acetyl zingerone methyl ether), added to both the dye and the aftercare (Chaudhuri et al., 2025). No independent test of vitamin E or resveratrol against dye fade was found. One extract (pomegranate) reduced UVA fading on red-dyed hair in a lab study, dye type not stated (Dario et al., 2013).
Between appointments, refreshing faded lengths with tone is the practical fix; the method is in refreshing mid-lengths and ends.
Why does red hair dye fade so fast?
Red is the shade family the fade research focuses on, and the one a patent applicant allowed the loosest fade limit, but no independent study has measured red fading faster than brown, blonde or black. Within auburn shades, one dye chemistry (pyrazole-based) faded deepest.
The patent signal is the Pratt application: its claimed 20-wash limit is ΔE 5.0 for red against 2.5 for blonde and darker shades. A looser limit suggests the applicant expected red to move more; it is a claimed ceiling, not a test result.
The chemistry signal is from Locke and Jachowicz, who used dyes "based on red couplers, such as 4-amino-2-hydroxytoluene and 1-naphtol" and found that "hair color based on pyrazole intermediates displayed the deepest fading". That compares chemistries within auburn shades. It does not compare red with brown or blonde.
A third study, Dario and colleagues (2013), found that red-dyed hair fades under UVA light. It tested red only and doesn't say whether the dye was permanent or semi-permanent, so it says nothing about red fading faster than other shades.
Red has the strongest reputation for fading, and it is the only shade family the fade studies tested, so brief red and copper clients at consultation and plan tone refreshes on the lengths rather than full re-applications. The method is in refreshing mid-lengths and ends.
Does permanent hair dye fade in chlorine?
No study measures whether chlorinated pool water fades permanent colour, and none covers heat styling either. The only relevant published statement is a patent application that counts bathing in the sea or a pool as washing, so treat a swim as a wash.
That application (US 2007/0251026) states that colour from "a direct or oxidation dyeing treatment gradually attenuates as a result of repeated washing", and defines washing to include "bathing, for example, in the sea or in a swimming pool". In practice, count pool days as wash days.
A green cast on lightened hair after swimming is a separate problem, deposited metal rather than lost dye, covered in neutralising brass and green bands.
Permanent hair dye fade: quick answers
Can permanent hair dye wash out completely?
No study we found shows it washing out: the lab work measured partial colour change. And because permanent colour also lifts some of the hair's own pigment as it develops (da França et al., 2015), faded hair isn't expected to return to its pre-colour shade. To take artificial colour out, see colour remover vs bleach bath.
How many washes does permanent hair dye last?
There is no published figure for permanent colour. The nearest is for demi-permanent, described as having "resistance up to 20 washes" (da França et al., 2015), and one patent application that claims fade limits after 20 washes under its own test.
Does semi-permanent fade faster than permanent?
Semi-permanent is designed to wash out: it goes in already coloured and isn't bound to the hair, so it fades gradually with washing (CTPA, the UK trade body). Permanent colour is formed inside the hair, and the lab studies measured partial colour change; no study we found compares the two directly.
Do darker shades last longer than red?
Red is widely reported to fade fastest, but no independent study has ranked shade families. Every fade study that names its shade tested red or auburn. One patent application allows red a looser fade limit (ΔE 5.0) than blonde, brown or black (2.5), which suggests the applicant expected red to move more; it is a claimed limit, not a measurement.
When should roots be redone?
When the regrowth shows against the target, not when the lengths fade. At average growth rates that is about 1 to 2 cm by six weeks (table above); on a high-contrast result, such as dark colour over white regrowth, it shows sooner than on a low-contrast result.
What this means for Life Color Plus clients
Life Color Plus is an ammonia-based oxidative permanent colour, the same category as the two main fade studies (Locke and Jachowicz; Zhou and colleagues), so the measured drivers apply: washing, light and hair type, with red the shade family most often flagged. No study has measured how Life Color Plus itself fades, and we don't claim it fades less than any other permanent colour.
What you control is the same as for any oxidative colour. Ask about wash frequency and sun at consultation. Set expectations early with lightened, white-haired and red or copper clients. When lengths have softened, refresh them rather than overlapping full permanent colour on the ends. All 160 shades, correctors and toners are £3.49 a tube.
At consultation, ask: How often do you wash? How much sun or swimming does your hair get? Is your hair lightened, or white? Is the target a red or copper?
Colour chemistry: questions colourists ask.
See also: Mixing Permanent and Demi Colour in the Same Bowl · Underlying pigment explained · Refreshing mid-lengths and ends
Shades: Life Color Plus tubes, £3.49
Sourced to Locke & Jachowicz (2005) and Zhou et al. (2009), both in the Journal of Cosmetic Science; Yun & Ahn (2023), Fashion and Textiles; Dario et al. (2013), Journal of Photochemistry and Photobiology B; da França et al. (2015), Cosmetics; the CTPA's consumer explainer on hair dye categories; Chaudhuri et al. (2025), International Journal of Cosmetic Science; Loussouarn et al. (2016), European Journal of Dermatology, for hair growth rates; and published patent applications US 2002/0124329 (Pratt; correspondence address Procter & Gamble) and US 2007/0251026 (Lalleman & Giroud). Always work to the instructions supplied with the product you are using.
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