Educational information, not medical advice — ask your doctor or midwife.
Henna is a dye from the leaves of a shrub, Lawsonia inermis. Dried and ground, the leaves make a green powder. Mixed with liquid, it stains skin, nails and hair red-brown.
In Hausa it is called lalle. Across West Africa it marks weddings, naming days and festivals. Pastes sold as "black henna" are different; they often hold PPD, a harsh dye that burns skin.
Henna is a proven dye. Health claims for it rest mostly on tradition and lab work. Long use is not proof of effect or of safety.
The stain itself is simple chemistry. Henna leaves hold a dye called lawsone. Lawsone sticks to keratin, the tough protein in skin, nails and hair.
That is why the colour lasts. It fades as stained skin cells flake away. Dyed hair keeps its colour until it grows out.
The health claims are far less settled. In test tubes, henna extracts slow the growth of some bacteria and fungi. Whether that happens on human skin is not established.
In animal studies, extracts have sped up wound healing and calmed swelling. These are early findings. They are not proof of a benefit in people.
One effect is well documented in people, and it is a harmful one. Henna can break apart red blood cells in people who lack an enzyme called G6PD. Babies and young children have been harmed this way, sometimes badly.
Henna reaches buyers in a few forms:
- Loose green leaf powder, sold by weight in markets and shops.
- Ready-mixed paste in cones, used for body art.
- Boxed hair dyes, sometimes blended with indigo or other plant dyes.
- Fresh or dried whole leaves, crushed at home in some rural areas.
- "Black henna" or "instant" paste, which is a PPD product and not safe for skin.
Traditional practice mixes the powder with water, lemon juice, tea or oil.
Some packaged hair products mix henna with chemical dyes. The label may not say so clearly.
Henna has a long and well-recorded past across Africa, the Middle East and South Asia. In Hausa communities it is known as lalle and is tied to celebration. Brides had hands and feet patterned before a wedding.
It was also used at naming ceremonies, at religious festivals and by men on the hair and beard. Patterns and their meanings differed from town to town.
Healers of the region put the paste on skin for heat rash, sores, burns and foot cracks. It was also laid on the soles to cool the body in hot weather. Some texts record it for scalp trouble and hair loss.
These records describe what people did. They do not show that the treatments worked.
Wash the paste off and get medical help the same day if the skin blisters, weeps or swells.
Go to an emergency department now if you or your child has any of these after henna use:
- Dark brown or cola-coloured urine - Yellow eyes or skin - Very pale skin, extreme tiredness or fainting - Fast breathing or a racing heart - Swelling of the lips, face or tongue, or trouble breathing
These can mean red blood cells are breaking down or a severe allergy is starting. Tell the staff that henna was used and on which part of the body.
In the United States, the FDA allows henna only as a hair dye, not for use on skin. Adding PPD to skin paste is illegal there and in the European Union, though such pastes are still sold in markets and at tourist stalls.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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