Henna use is thought to date back to 7th century BC.1
Henna offers glossy, richly-hued locks without the damage associated with most chemical hair dyes.
But what exactly is henna? What advantages does it offer over regular hair dye? Are there any risks? And is it true that you once you start using henna, you can’t go back?
We take a look at henna and whether it might be the right choice for your hair.
What is henna hair dye?
To make henna hair colour, the leaves of the lawsonia inermis – or henna plant – are harvested and ground into fine, richly pigmented powder.2 This powder is then mixed with liquid to create a thick, mud-like paste which imparts a deep stain on hair.
Pure henna is often mixed with different plants to offer different colour results. These include:
- Cassia plant powder for lighter shades like strawberry blonde and coppery red (from light starting shades – cassia won’t lighten hair).
- Indigo plant power for dark shades like chocolate brown, auburn, burgundy and black.3
As a rule of thumb – using pure henna alone will result in a deep red henna tone, then the more indigo is added to the mix, the darker and deeper the colour.4
What are some advantages of using henna in place of regular hair dyes?
1. It’s natural
Henna is formulated without the chemicals and additives often found in hair dye. These include toluene, para-phenylenediamine, and lead acetate.
2. It doesn’t damage the hair
Unlike the weakening effect of most chemical hair dyes – which have been known to roughen and damage the cuticle in order to impart the colour – henna strengthens and protects hair strands by binding with the hair’s cuticle and strengthening it from within.5
3. It’s gentler on the scalp
Henna has a pH of around 5.5 – much closer to that of skin than any chemical hair dye.6 This means the tingling, itching or burning associated with box dyes won’t happen with henna.
This gentle pH also helps reduce cuticle damage and hair fibre breakage.7
Henna is a natural plant used as a hair colourant
Henna is gentle on the hair and scalp
Different plants can add different shades to natural red henna
What are some disadvantages of using henna instead of regular hair dye?
1. Unreliable colour results
The colour results of henna can be somewhat unpredictable – especially if you’ve got lots of greys or have previously dyed your hair. The variations in tone and condition cause each strand to pull the henna pigment differently, creating a range of shades.
We recommend a strand test beforehand.
2. Application can be messy
Don’t let the messy nature of henna application take you by surprise. Once mixed, henna’s consistency is like watery mud, which can get everywhere. And did we mention it stains?!
3. It’s difficult to cover if you fancy a change
It’s true the deep stain henna leaves on the hair is difficult to shift. As henna binds with the hair cuticle, any dye applied on top may not take properly.
The horror stories of hair going up in smoke are the result of metallic salts – an additive often used in pre-mixed henna dyes – not the henna itself.8
Are there any risks to using henna?
You may have heard of people experiencing allergic reactions to ‘black henna’, the type used in black temporary tattoos. This stuff isn’t henna at all, but a chemical dye called para-phenylenediamine.9 This commonly causes allergic reactions and anything purporting to be black henna for hair or black henna hair dye containing this ingredient instead of natural henna should be avoided.10
Pure henna made from the henna plant is generally very safe to use and well-tolerated.11
How to use henna for dying hair
Step 1: Choose your henna
You have two options – henna powder or pre-mixed henna dye. The pre-mixed stuff might be better for beginners as the addition of liquid and/ or other plant dyes is done for you.
Be sure to check that the pre-mixed product you use is made of pure henna and plant dyes, with no additives, chemicals or metallic salts.12
If you do go for powder – you can either use it alone or combine it with another plant powder – such as indigo or cassia – to your desired depth. Then, you’ll need to combine it with a warmed acidic liquid (lemon juice, vinegar or orange juice all work!) until you reach a smooth mud-like consistency.13
Rest the covered mixture for a few hours at room temperature to give the dye pigments a chance to release.
Step 2: Application
This is the fun (and messy) part. Have several old towels at the ready, wear gloves and prep your hairline with barrier cream like petroleum jelly before you begin.
Apply the henna paste thickly to your hair section by section. You’ll need lots of product to really coat each strand.
Cover with loose cling film or a shower cap.
Step 3: Development
Unlike most hair dyes which need well under an hour to develop, natural henna takes its time.
Leave henna on the hair for 3 – 6 hours. Colour result can depend on the original colour and condition of the hair, but generally deepens and darkens the longer you leave the henna on the hair.
Step 4: Rinsing
Using gloves, rinse your hair using the showerhead for as long as it takes for the water to run completely clear. No need to shampoo or condition. After gently towel-drying, follow with your favourite serum or hair oil.
If you feel the colour isn’t strong enough, you can repeat the process after a day or two to achieve a deeper result.
How long does henna last on hair?
This depends on the condition of your hair and how often you wash it, but henna usually stays vibrant for around 2 months before gradually fading. The henna tint may never completely leave the hair.
A henna shampoo may help you keep the vibrancy longer- although these don’t add colour to your hair.
Can henna damage your hair?
No – pure henna is not damaging to the hair as it doesn’t roughen or strip the hair’s cuticle. In fact, henna usually makes hair stronger and shinier.
Does henna cover grey hair?
Using henna on grey hair can be a great way to add a tint – although be aware that grey strands might not pick up henna the same way as other strands do as they tend to be coarser.
Colour results can be variable with henna – always do a strand test
Henna strengthens the hair fibre
Henna fades gradually but the colour never washes out
Last updated: 11 February 2021
Reviewer: Manisha Taggar
Manisha started her career at a Cosmetics distributor as a Regulatory Technologist followed by a Regulatory Affairs Officer, ensuring the regulatory compliance of cosmetic products from colour cosmetics to skincare. After 3 and half years in this role, Manisha joined Holland & Barrett as a Senior Regulatory Affairs Associate in 2019. Manisha specialises in Cosmetic products, both own-label and branded lines, ensuring that these products and all relating marketing material comply to the EU Cosmetics Regulation.