Black henna and hair colour: the question you must ask

What 'black henna' is doing in a hair conversation

Natural henna is a plant dye, typically orange-red. 'Black henna' used on streets and beaches is often henna mixed with a high dose of PPD so it dyes skin black quickly. PPD is also the family of dye that makes permanent hair colour work. A skin tattoo with a slug of PPD can sensitise someone who has never had a salon colour. Weeks or years later, a normal tint can produce a serious reaction.

That is why the question is not small talk. It is one of the few history questions that changes whether you should colour them at all, or at least whether you should stop and read the IFU and your insurer before you mix.

This is a working explanation for people who do the job, not legal, insurance or medical advice. Read your own policy, your local authority, and the current wording from the bodies named. Glow records what you set. It does not decide the rule and it does not claim a salon is compliant.

The question, in words you can actually say

Have you ever had a black henna tattoo — the kind that goes on in a market or on holiday and dyes the skin black? Have you ever had a reaction to hair colour, including at home? Have you used colourants before?

The CTPA's public material has long grouped previous colour use and black henna together. Manufacturer IFUs often print a version of the same. Use their wording if they print it. Do not shorten it to 'any allergies?' — people do not file a beach tattoo under allergies.

If they say yes

Stop and treat it as a high-risk history, not as a fun story about Magaluf. Read the IFU. Many tell you not to colour. Some tell you to get medical advice first. This is not the moment to 'just do a skin test and see' unless the manufacturer and your insurer clearly allow that path.

A skin test that looks fine is not a promise. Sensitised clients can still react. If you refuse the colour, write down that you asked, they answered yes, and you did not proceed. That record protects both of you.

If they say no, or they are not sure

No is not a free pass. They still need the allergy alert test your policy requires. Not sure is common — people forget a tattoo from ten years ago. Show a photo of what black henna looks like on skin if you have to. If they remain unsure, you are in judgement territory: test, refer, or refuse. Write down what they said.

Where to put the answer

On the consultation, required, dated, signed, next to the skin-test result and the batch you then used. A verbal 'yeah fine' at the basin disappears. If they book online, the question has to be in the form they cannot skip.

Glow consultation questions can be required before checkout. Hair categories use allergy-alert language. See Glow for hair salons and allergy alert test rules.

Tint, lashes and PMU

Black henna is a hair-colour conversation first because of PPD in oxidative dye. Some tints and some adhesives sit in related chemical families. If a client reports a black henna history and you are about to put a dye or an adhesive on them, read that product's IFU rather than assuming hair rules apply unchanged.

Do not copy a hair form onto a lash client and call it done. Do ask about previous reactions to dye, tint and adhesive in language they understand.

What the waiting area should already know

A lot of clients have never heard the phrase black henna. They remember 'that tattoo on the beach that stained for a fortnight'. Put a line on the booking form and, if you have a colour menu on the wall, a line there too. People answer more honestly when they understand why you asked.

Home colour counts. Box dye from a supermarket is still oxidative colour. If they say they only ever do it themselves, that is previous colour use. The CTPA-style question is not only about salon visits.

Teenagers on holiday are the classic black-henna story. They are also the ones who will sit for a first salon colour before a prom. Ask. Do not assume a first salon visit means a first exposure to PPD.

What Glow will not do

Glow will not diagnose a PPD allergy. It will not tell you it is safe to colour. It will store the question, the answer, the test and the batch. Pricing is £19 a month.

If a client is offended that you asked, that is information. People who had a bad street tattoo sometimes do not want to talk about it. Ask anyway, privately, not as a joke at the basin in front of the rest of the salon. Write the answer they gave, not the answer you wished they gave.

Keep a copy of the IFU for the colour you use most. When someone says yes to black henna, you want the manufacturer's sentence in your hand, not a memory of a course from 2018.

Colourists who also do brows or lashes should not assume a 'no' on the hair form covers a tint. Ask again on that category if the product is a dye. People answer the question in front of them, not the one you asked last year on a different service.

If they had black henna and you refuse, offer a non-oxidative option only if you are sure it is actually non-oxidative and the IFU allows it. A lot of 'henna' hair products are not henna. Read the INCI, not the front of the box. If you are not sure, do not colour. Book a consult with no product, or send them to their GP. Either is cheaper than guessing with PPD. Write the refusal on the client so the next colourist in the building does not start from a blank chair. A verbal no in the office is not a record. Put it on the client the same hour you said it. Do not wait until close.