Henna is permanent on hair — it does not wash out. Once the dye molecule (lawsone) binds to your keratin, that colour stays until the strand grows out or is cut off. What changes over time is intensity: the stain looks its deepest after it oxidises over 24–48 hours, holds strongly for about 4–6 weeks, then slowly softens as it is exposed to sun, washing and heat. Because your hair keeps growing, most people do a roots touch-up every 3–4 weeks even though the length still holds colour. On skin it is a completely different story — a henna body-art stain lasts only 1–3 weeks. Here is the full timeline.
Why henna lasts so much longer on hair than on skin
The difference comes down to what the dye binds to. On your scalp hair, lawsone bonds with keratin in strands that are not shed, so the colour is effectively permanent on that section of hair. On skin, it only stains the outermost layer of dead cells (the stratum corneum), and those cells naturally flake away within a couple of weeks. That is why the same cone can leave a two-week design on your hand but a months-long colour in your hair. If you are asking specifically about body art, our guide on how long henna lasts on skin covers that timeline in detail.
The henna-on-hair timeline, week by week
| Stage | What you see |
|---|---|
| First 24–48 hours | Colour oxidises and deepens; a fresh orange-red matures toward its true reddish-brown or brown tone. |
| Weeks 1–2 | Peak richness and shine; colour is at its most vivid. |
| Weeks 3–4 | Still strong on the length; new growth appears at the roots and starts to show. |
| Weeks 5–8 | Length softens slightly with washing and sun; most people refresh roots around now. |
| Beyond 8 weeks | Length keeps a warm tint that builds with each application; henna is cumulative, so repeat dyeing deepens the overall colour. |
What makes henna fade faster (and how to slow it)
Colour longevity is mostly about how well the dye released in the first place and how you treat it afterwards. Chlorine, sun exposure, hot water, clarifying shampoos and frequent washing all lift tone over time. To keep it rich: let the paste sit long enough (typically 2–4 hours, longer for deeper tones), rinse without shampoo for the first 24–48 hours so oxidation can finish, and wash less often with a gentle, sulphate-free shampoo. Our henna aftercare guide has the full routine for a darker, longer-lasting result, and how you mix the henna powder in the first place makes a big difference to release.
Does henna grow out or wash out?
It grows out. Unlike a semi-permanent chemical dye that fades evenly and rinses lighter over a few weeks, henna stays put on the strand it coloured. You will see a line of new growth at the roots rather than an all-over fade, which is why roots are the part that needs refreshing. This also means henna cannot be “stripped” the way some chemical colours can — it has to grow out or be cut. If you are deciding between the two, our honest comparison of henna vs chemical hair dye lays out the trade-offs.
How long does henna last on grey hair?
Greys take henna well but read brighter, so pure henna on grey often looks coppery. For a deeper brown or a soft black, henna is layered with indigo — never with PPD. That combination is permanent on the grey strand just like any other, though because grey regrows visibly, roots on grey hair usually need attention every 2–3 weeks. We walk through the two-step method in covering grey hair with henna and indigo.
A quick safety note before your first application
Real henna stains reddish-brown and takes hours to develop. Any product promising an instant, jet-black result in an hour is not pure henna — it may contain PPD, which can cause serious skin reactions. Freegrin henna is always PPD-free; our darker shades get their depth from indigo, and you can read exactly what PPD is and why to avoid it. Whichever brand you use, do a 24-hour patch test before every first use — apply a small amount to the inner forearm, wait a full 24 hours, and only proceed if there is no reaction. Henna is plant-based, but no dye can be promised safe for everyone, so the patch test is not optional. Building a gentler, more natural routine overall? Many henna users also switch their oral care — here is our beginner’s guide to the miswak stick, a plant-based, zero-waste toothbrush.
Frequently asked questions
Does henna hair colour wash out?
No. Henna binds permanently to the hair strand, so it does not wash out. The coloured length stays until it grows out or is cut; only new root growth shows a change.
How often do I need to reapply henna?
The length holds colour for weeks, but because hair keeps growing most people refresh their roots every 3–4 weeks (every 2–3 weeks on visible grey). A full-length application is only needed when you want to deepen the overall tone.
Does henna fade over time?
The length does not fade the way chemical dye does, but the tone softens gradually with sun, chlorine and washing. Henna is cumulative, so repeat applications build a richer, longer-lasting colour.
How long should I leave henna on my hair?
Usually 2–4 hours for a rich result, and longer for the deepest tones. Leaving it on longer improves dye release; the exact time depends on your mix and target shade.
Can I dye over henna later?
Henna cannot be stripped, so a later chemical colour may react unpredictably over it. The safest path is to henna again, layer indigo for depth, or grow it out. Always patch test first.
Want a colour that lasts? Start with Pure Red or Deep Brown henna powder, or browse the full PPD-free henna powder range — ships from Hong Kong or Germany, with a 24-hour patch test always recommended first.