Why grey hair resists colour
Grey and white hairs have little or no melanin, so dye has nothing underneath to blend with. Grey hair can also be coarser or more tightly closed at the surface, which some people find makes it slower to absorb colour. That's why a shade that looks right on pigmented hair can come out lighter, brighter or patchy on grey.
Choosing a shade to cover grey
- Use a natural base. Shades marked as natural (often .0 or N) give opaque coverage, while pure fashion tones such as ash or copper can look see-through on grey.
- Go a little lighter. As grey increases, skin often looks better with a shade one level lighter than your old natural colour, and very dark colour on lots of grey shows a harsh regrowth line sooner.
- Mind the tone. Ash can look flat on grey, and a small amount of gold or beige often looks more natural. Use the colour wheel if you're correcting a cast.
Permanent or demi-permanent for grey hair
| Goal | Usual choice | Notes |
|---|---|---|
| Full coverage | Permanent colour, usually with 20 vol developer | Most reliable on resistant grey. Grows out with a visible root. |
| Softening and blending | Demi-permanent | Gives a partial, translucent result on grey that fades gently. |
| A light tint | Semi-permanent | Stains grey slightly. Washes out over a few weeks. |
| Growing grey out | Highlights, lowlights or gloss | Breaks up the line between dyed and natural hair. |
The dye types comparison explains each one in more detail.
How to touch up grey roots
- Patch test 48 hours before each application.
- Apply colour to new regrowth only, overlapping as little as possible onto previously coloured hair.
- Leave for the full time on the pack. Grey usually needs the full development time.
- Only take colour through the lengths for the last few minutes if they've faded, and only if the instructions allow.
Most people touch up roots every four to eight weeks, depending on how fast their hair grows and how much grey they have.
When grey still shows after colouring
If grey still shows after the full time, the shade may be too light or too fashion-toned. Choose a natural base shade or mix one in as the product instructions allow, and check you're using the developer strength the brand recommends for grey. A salon colourist can pre-soften resistant hair if needed.
Henna and plant dyes on grey hair
Pure henna gives orange-red on grey, and the colour builds with each application. It's very difficult to lighten or change later. Products sold as "black henna" may contain PPD, sometimes in high amounts, and can cause severe reactions. Check every ingredient list.
Grey coverage questions
Why won't my grey hair hold colour?
Grey has little or no melanin, so dye has nothing to blend with, and some grey hair absorbs colour slowly. A natural base shade and the full development time usually help.
How often should I touch up grey roots?
Most people touch up every four to eight weeks, depending on how fast their hair grows and how much grey they have.
Will demi-permanent colour cover grey?
It blends grey with a translucent result that fades gently. For full coverage, permanent colour is usually more reliable. The maintenance guide covers keeping either looking fresh.
Safety first. Do an allergy patch test 48 hours before every permanent or demi-permanent colour, even a brand you have used before, and a strand test to check the result. Many oxidative dyes contain PPD (para-phenylenediamine) or related chemicals that can cause serious allergic reactions. This site gives general information, not medical advice: if you react, rinse the product off and get medical help.