Your guide to henna hair dye

Henna is a natural plant dye with a history stretching back to at least the 7th century BC. It’s long been used not only for body art but also to give hair a rich, glossy colour without the damage that often comes with conventional dyes.

But what exactly is henna hair dye, how does it compare to regular dyes, and are the rumours true — once you use it, can you never go back? Let’s take a look.

What is henna hair dye?

Henna hair dye is made by grinding the leaves of the lawsonia inermis plant into a fine, deep green powder. When mixed with liquid, it forms a thick, mud-like paste that stains hair with a long-lasting colour.

Pure henna yields a deep red tone, but it’s often blended with other plant powders to modify the shade:

  • Cassia: Produces lighter tones like strawberry blonde or copper when used on light hair (it won’t lighten darker shades).
  • Indigo: Darkens the mix to create shades like auburn, chocolate brown, burgundy or even black.

Generally, the more indigo in the mix, the darker the final result will be.

What are the benefits of using henna hair colour instead of regular hair dyes?

Thinking about swapping your usual box dye for a natural red henna? Here are a few reasons why that might be worth it.

1. It’s plant-derived

Henna is made from plants and doesn’t contain harsh synthetic chemicals like toluene or para-phenylenediamine (PPD), which are known allergens and irritants for many people.

2. It doesn’t weaken the hair to colour it

Permanent dyes change the internal structure of hair, often leaving it weakened and brittle. Henna works differently — it coats the hair shaft rather than penetrating it. That coating not only colours but can also leave hair feeling stronger and better protected, rather than damaged.

3. It has fairly neutral pH

Henna’s pH sits around 5.5, which is closer to the natural pH of your scalp and skin. Most chemical dyes are far more alkaline, which can disrupt the hair’s cuticle and lead to breakage. Henna’s lower pH makes it a gentler alternative.

Drawbacks of using henna hair dye

1. Natural colour variation

The final shade you get from henna can vary depending on your natural colour, greys, or any previous dyes. The result might not be perfectly uniform, so a strand test is essential before a full application.

2. Application can be messy

Henna paste has a mud-like texture and can get messy quickly. Make sure you protect your clothes, floors, and furniture before starting, and wear gloves during application.

3. It’s difficult to cover if you fancy a change

Once henna binds with your hair cuticle, it’s not easy to dye over. Traditional hair dyes may not take properly on top of henna, which could limit your future colour options.

How to dye your hair with henna

Whether you're going for a bright red or rich brunette tone, the basic henna process is the same.

Step 1: Choose your henna

You can either buy pure henna powder or opt for a pre-mixed paste. Pre-mixed versions are convenient for beginners since the dye is already blended and ready to use.

If using powder, combine it with an acidic liquid like lemon juice, orange juice, or vinegar to form a smooth paste. For custom colour results, mix with cassia or indigo as desired. Let the mixture sit at room temperature for several hours to allow the dye to activate.

Step 2: Patch test

Always perform a patch test 24–48 hours before using henna to check for allergic reactions. Discontinue use if you notice any redness, itching, or other irritation.

Step 3: Application

Apply a protective barrier cream around your hairline. Wear gloves and old clothes or towels you don’t mind staining. Apply the paste in thick layers, section by section, until your hair is fully coated. Then wrap it in cling film or pop on a shower cap.

Step 4: Development

Henna needs much more time to develop than chemical dyes. Leave it on for 3 to 6 hours, depending on your desired depth of colour and hair type. The longer it sits, the richer the result.

Step 5: Rinsing

Rinse thoroughly with water using gloves. Avoid shampoo or conditioner right after rinsing. Once the water runs clear, gently towel-dry and apply serum or oil if desired. If the colour isn’t intense enough after the first try, you can repeat the process after a day or two.

Are there any risks to using henna?

Allergic reactions are usually linked to so-called “black henna,” which often contains PPD — a synthetic chemical that can cause serious side effects. This isn’t true henna, and it should be avoided for both skin and hair use.

Natural henna made purely from the henna plant is generally very safe and well-tolerated.

Henna FAQs

How long does henna last on hair?

The colour typically stays vibrant for about two months, though fading depends on your hair type and washing habits. Some residual colour may remain permanently.

Can henna damage your hair?

No — pure henna doesn’t damage the hair, and in most cases, leaves it stronger and glossier than before.

Can you use henna for grey hair?

Yes, henna can add beautiful reddish tones to grey hair. However, grey strands may take colour differently due to their rougher texture, sometimes leading to uneven absorption — especially at the roots. This happens with chemical dyes too, so it’s not unique to henna.

To get the best outcome, choose a slightly lighter shade than your desired goal. That way, it’s easier to go darker later if needed. When using henna on grey, allow at least 72 hours between applications so the pigments can fully oxidise and settle.

Summary

  • Henna results can vary, so always do a strand test first
  • It strengthens and protects the hair fibre
  • Henna fades gradually but doesn’t wash out completely

The final say

If you're after a natural way to colour your hair without the usual chemicals, henna could be your answer. Just make sure you follow the proper method for the best results.

Disclaimer

If you have sensitive skin, eczema, psoriasis, acne or rosacea, consult a dermatologist before trying any new techniques.

Sources