Mehndi for Hair Colour: Pure Henna Recipe and Indigo Two-Step
If the henna packet promises black hair in 30 minutes, it isn’t just henna. Pure mehndi for hair colour gives orange to deep copper-red, takes hours, and needs a second step with indigo to go brown or black. That “instant black” is usually PPD, a chemical that can cause severe allergic reactions. Here’s how to make and use the real thing.
“Kala mehndi” or “black henna” products that colour hair or skin black fast often contain para-phenylenediamine (PPD), a hair dye chemical. On skin or scalp, it can cause blistering, weeping rashes, swelling of the face, and in rare cases serious whole-body allergic reactions. A reaction can also leave you permanently allergic to many hair dyes. If your scalp burns, itches intensely or swells after any henna, wash it out immediately and see a doctor, urgently if your face, eyes or throat swell. Never apply henna to babies or young children, especially those with G6PD deficiency, in whom henna can cause dangerous breakdown of red blood cells. If you’re pregnant or breastfeeding, use only pure, patch-tested henna and ask your doctor if unsure.
At a glance
- Colour from pure henna: orange on grey, copper to red-brown on dark hair
- Powder needed: about 100 g for shoulder-length, 200 to 300 g for long thick hair
- Dye release: 4 to 8 hours rest in a warm room
- On hair: 2 to 4 hours
- Patch test: 48 hours, every new packet
- For brown or black: indigo, applied as a second step
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Buying pure henna
Pure henna is the ground leaf of Lawsonia inermis and nothing else. When you read the ingredients, you want one word.
- Colour: fresh henna powder is green to khaki, and smells grassy, like hay or tea. Brown, dusty powder with no smell is old.
- Texture: finely sifted, silky. Grit or sand means poor sieving.
- Label: avoid “black”, “brown”, “burgundy” or “natural black” henna unless ingredients clearly list only plant powders (henna, indigo, cassia).
- Avoid: “compound henna” with metallic salts, which can react badly with chemical dyes and perms.
- Store: in a sealed bag in a cool, dark place. For long storage, freeze. Humidity weakens it.
Quick home test for dye strength, once the patch test below has come back clear: mix a teaspoon of powder with a little water, dab on your palm for 10 minutes, rinse. A clear orange stain that darkens over a day means active dye. Barely any stain means stale powder.
The patch test (don’t skip it)
- Mix ½ teaspoon of the henna with enough water to make paste.
- Apply a 1 cm dab behind one ear or on the inner elbow.
- Leave for 1 hour, then rinse gently.
- Watch the spot for 48 hours. Any itching, redness, bumps, swelling or blistering means don’t use it.
A clear patch test lowers the risk but can’t promise you won’t react later. Never patch test a product you suspect is black henna; just don’t use it. If you’ve ever had a reaction to a black henna tattoo or a hair dye, avoid henna mixes of unknown make and tell your doctor before colouring your hair with anything.
Also do a strand test: snip a small lock of hair from a hidden spot (or collect some from your comb), apply paste, and see the colour after 24 hours. Especially useful if your hair has chemical dye, keratin or relaxer treatments.
Mehndi for hair colour: the pure henna paste recipe
This makes enough for shoulder-length, medium-thick hair.
- Put 100 g of pure henna powder in a glass, steel or plastic bowl.
- Slowly add about 250 to 300 ml of lukewarm water (or cooled, strained black tea for richer tone), stirring well. Aim for a paste like thick yoghurt, smooth with no lumps.
- Optional: add 1 tablespoon of lemon juice or amla powder for a slightly deeper tone. Lemon can make hair drier, so skip it if your hair is dry.
- Press cling film onto the surface of the paste to stop it drying.
- Leave at warm room temperature (around 25°C) for 4 to 8 hours. Dye is ready when the top layer turns slightly darker brown when you lift the film.
- Before applying, stir in a little more water if it has thickened. You don’t want it runny.
- Wash hair with shampoo only, no conditioner or oil. Towel dry.
- Wear gloves. Apply petroleum jelly along the hairline and ears to avoid staining.
- Section the hair and apply thickly from roots to ends, like icing a cake, starting where grey is most visible.
- Pile hair up, cover with a shower cap or cling film, and leave for 2 to 4 hours. Longer gives deeper colour.
- Rinse with plenty of lukewarm water until it runs clear. A conditioner helps slide out the grit. Avoid shampoo for 24 to 48 hours.
Colour darkens over 2 to 3 days as it oxidises. Don’t judge it on day one.
Fresh henna is green, smells like hay, and takes its time. Anything faster is something else.
The indigo two-step for brown or black
Indigo (Indigofera tinctoria) powder stains blue. Over a henna base, it turns copper into brown or black. Indigo has to go on after henna for most people, not mixed and definitely not alone, or grey hair can turn greenish-blue.
- Do the full henna step above and rinse. Towel dry hair.
- Right before use, mix 100 g of indigo powder with about 250 ml of warm water and a pinch (¼ teaspoon) of salt into a yoghurt-like paste. Don’t rest it; indigo loses strength after 15 to 20 minutes.
- Apply straight away in thick sections, roots first.
- Cover and leave 1 to 2 hours. Longer for darker black.
- Rinse with water only. No shampoo for 48 hours.
For a softer brown, some mix henna and indigo half and half (1:1) in one paste and apply for 2 to 3 hours; the result is lighter and less predictable than the two-step. Always patch test indigo separately.
Henna has been used for centuries across South Asia, the Middle East and North Africa, for weddings, Eid and hair. In Unani tradition, henna is considered cooling and drying in temperament, and was applied to the scalp in hot weather and to hands and feet for coolness. Ayurveda also describes it as cooling. Many families mixed it with tea, coffee, katha or amla for tone. Treat these as traditional uses, not medical effects.
Honest pros and cons
- Pros: covers grey with a warm colour, gives hair a glossy, thicker feel, no ammonia or peroxide, lasts well.
- Cons: messy, slow, can dry out hair, can’t be lightened afterwards, grey often goes bright orange at first, and chemical colouring over henna may give unpredictable results.
- Dry hair tip: add 1 tablespoon of plain dahi to the paste, or oil hair the night before your next wash. See our methi hair mask guide for a conditioning follow-up, and our champi guide for oiling between applications.
If your scalp has dandruff or sores, sort that first; our dandruff home remedies article helps. More traditional hair care, including reetha and shikakai washing, is in Desi Remedies.
Henna questions
Does mehndi colour hair black?
Pure henna alone never does. It gives orange on grey and copper to red-brown on dark hair. For brown or black you need a second step with indigo over the henna. A packet promising black in 30 minutes almost certainly contains PPD, a chemical dye.
What is black henna and why is it dangerous?
“Kala mehndi” that colours fast usually contains para-phenylenediamine (PPD). It can cause blistering, weeping rashes, facial swelling and occasionally serious whole-body allergic reactions, and it can leave you allergic to many hair dyes for life. If your scalp burns or swells, wash it out and see a doctor, urgently if your face or throat swells.
How long should I leave henna on my hair?
Two to four hours on the hair, covered with a shower cap. Longer gives a deeper colour. Remember the paste itself needs 4 to 8 hours of resting in a warm room beforehand so the dye is released.
How do I know if henna powder is pure?
The ingredients should say only henna (Lawsonia inermis). Fresh powder is green to khaki, silky and smells grassy, like hay or tea. Avoid anything labelled black, brown or burgundy unless it lists only plant powders, and skip compound henna with metallic salts.
Why did my grey hair turn orange?
That’s simply how pure henna shows on white hair. It deepens over 2 to 3 days as it oxidises, and a second application or the indigo step turns it towards auburn, brown or black.
How do I get dark brown or black with henna and indigo?
Do the full henna step, rinse and towel dry. Then mix indigo with warm water and a pinch of salt, apply straight away, and leave 1 to 2 hours before rinsing with water only. Indigo on its own can turn grey hair greenish-blue, which is why henna goes first.
How often can I apply henna to my hair?
Root touch-ups every 4 to 6 weeks are common. Putting it on full length every time builds up dryness, so after the first few applications, focus on the regrowth.
Is henna safe in pregnancy?
Pure, patch-tested henna on the hair is widely used in pregnancy and while breastfeeding. Avoid black henna completely, and ask your doctor if you have a history of allergy or G6PD deficiency in the family.
Can children use henna on their hair?
It’s not recommended for young children and should never be used on babies, because in children with G6PD deficiency henna can break down red blood cells dangerously. For older children, only pure henna after a patch test, and never black henna.
How do I do a patch test for henna?
Put a 1 cm dab of paste behind one ear or on the inner elbow, rinse after an hour, and watch it for 48 hours. Itching, redness, bumps or swelling mean don’t use it. Repeat with every new packet, and never patch test something you suspect is black henna.
Can I use henna over chemically dyed hair?
Pure henna usually can go over it, but results vary, so do a strand test on a hidden lock first. Keep compound henna with metallic salts away from chemically dyed, permed or relaxed hair.
Does henna make hair dry?
It can. Skip lemon juice in the paste if your hair is dry, add a tablespoon of plain dahi instead, and oil your hair the night before your next wash. Conditioner during the rinse also helps.
Should I wash my hair after applying henna?
Rinse the paste out with plenty of lukewarm water, using conditioner to help slide out the grit, but avoid shampoo for 24 to 48 hours. After indigo, skip shampoo for 48 hours so the colour settles.
Can I lighten or dye over henna later?
Henna can’t really be lightened, and chemical colour on top can give unpredictable results. Strand test any dye first and tell your salon you’ve used henna.
How long does henna paste keep?
Mixed henna paste keeps about a day at room temperature, a few days in the fridge, or several months frozen in a sealed bag. Indigo is different and must be used within 15 to 20 minutes of mixing.