Salon Patch Test Rules UK: The 48-Hour Guide

A colour appointment is the only booking in your diary that depends on something that had to happen two days earlier. Here is how the patch test rules work, and how to run them without losing chair time.

The short version

An allergy alert test, the one everyone calls a patch test, should be done at least 48 hours before a colour service. For a returning client on the same product and shade, the salon protocol lets you test every six months instead of every visit, as long as the questionnaire supports it. Each brand needs its own test. The date, product, result and decision go on the client record card, signed by both of you.

The awkward part is not the test. It is that the test is a separate event, two days early, for a service worth three or four times a cut. Get the diary side right and colour bookings stop falling over on the day.

The rest of this guide covers what the rules actually say, where the popular "it's the law" line is wrong, and a booking routine that holds up on a busy Saturday.

What the rules actually say

The current position comes from a harmonised professional testing protocol announced in January 2024 by the Hair & Barber Council, the NHBF, the Good Salon Guide, the Fellowship for British Hairdressing and other industry bodies. It brings the UK in line with Cosmetics Europe Recommendation No. 27, published in 2023.

Four points matter for your diary.

Forty-eight hours, minimum. The NHBF's 2025 factsheet is direct about it: allergy alert tests "should be done at least 48 hours before the service is carried out. This is because it can take up to 48 hours for an allergic reaction to develop." How far in advance you are allowed to go is set by the manufacturer, not by you, so read their protocol.

Six months, with conditions. Manufacturer instructions for many hair dyes ask for a test before every single use. That would be unworkable for a salon, which is why the protocol exists. It uses a questionnaire so a returning client having the same service with the same product can be tested every six months instead. Questions seven and eight of that questionnaire cover the two things that reset the clock: a change of brand or product, and more than six months since the last test. The NHBF's own guidance on what to do when you are unsure is worth repeating word for word. "If you are in any doubt about whether the protocol applies to your situation, then follow the manufacturer's instructions."

One test per brand. Different brands use different ingredients, so a client having two brands used on them needs two tests. You can usually do them at the same sitting if the manufacturer allows it, as long as the tests do not overlap and you record where each one went.

Some clients you do not colour at all. Not under 16s. Not anyone with a rash or an irritated or damaged scalp. Not anyone who has ever reacted to a colour service, or to a temporary "black henna" tattoo. And when the client comes back in, you do a visual check of the test area before you start.

The harmonised method itself is quick. Mix a pea-sized amount of colorant and developer, spread it thinly on the inner forearm, leave it uncovered for 45 minutes, then wash and pat dry. The client does not sit in your salon for those 45 minutes. They go home. They watch the area for the 45 minutes and for the 48 hours after, and they tell you if anything changes.

Where the "it's the law" line goes wrong

Search for this topic and you will find salon websites stating that patch testing is a legal requirement under section 3 of the Health and Safety at Work etc. Act 1974. That is a bit too neat, and it is worth knowing why before you put it in your own client-facing wording.

No UK statute names patch tests. Section 3 is a general duty: you must conduct your business so that people who are not your employees "are not thereby exposed to risks to their health or safety", so far as is reasonably practicable. It does not tell you how.

What actually holds you to testing is four things stacked together. The general duty above. The UK Cosmetics Regulation, under which hair dyes are safety-assessed and must carry warnings such as "can cause severe allergic reactions" and "not intended for use on persons under the age of 16", which you are expected to follow. Your insurance policy conditions, which are usually the sharpest of the four. And plain negligence liability if a client is injured.

The practical upshot is the same. You test. But the accurate version is more useful, because it points at the document that decides whether you are covered: your policy wording. The NHBF's guidance says to check it, and to tell your insurer immediately if a client reacts, because that is a potential claim.

Three ways to test, and what each does to your diary

The protocol recognises three systems. They are not equivalent from a booking point of view.

The manufacturer's own allergy alert test, done by you, in the salon. Cheapest, and it tests the actual product. It also costs you a second client visit and a slot in the diary two days before the colour appointment.

A professional protocol test, also done by a hair professional. Brand protocols cover only that brand's products, while some trade body and insurer protocols can be used with any colour brand. Same diary cost as above.

A universal allergy screening test licensed as a medicine, which the client applies at home. Colourstart is the one most UK salons use. It screens for PPD, the most common hair colour allergen, and because it is a licensed medicine it cannot be given away free. RRP is £15 including VAT. Its own guidance is that a client should not use it more than once if you are applying their usual colour product, though it may be repeated if you switch product, and clients complete a short questionnaire before each colour service. Importantly, you should not do a manufacturer test as well as this one, because repeated exposure to PPD can itself cause sensitisation.

One thing the protocol rules out flatly: decanting colour from its original packaging and posting it to clients for an at-home test. It says this goes against best practice and "may invalidate insurance cover". If your salon started doing that during lockdown and never stopped, stop.

What a missed test actually costs

Colour is the money. Take Headmasters, whose UK price list is public: regrowth permanent colour starts at £58, full-head permanent runs to £95, extended regrowth bleach and tone reaches £145, and full-head balayage or highlights sit between £130 and £177, with a blow-dry on top. Their client-facing rule is a good example of the shape most salons land on. "If you have not had your hair coloured at Headmasters in the last 6 months, are pregnant, have had changes to your health condition or you have previously had a reaction to a colour service you must undergo a skin patch test 48hrs prior to your appointment."

Now picture that booking falling over at 10am on a Saturday because nobody checked. You lose two to three hours of a stylist's day at short notice, not the 30 minutes a cut would cost you. That is the real reason this is a salon problem and not a barbershop one. If you have never put a number on it, our no-show cost calculator does the arithmetic, and the numbers are the same whichever chair is empty.

A booking routine that holds up

None of this needs new software. It needs the question asked at the right moment.

Ask at the point of booking, not the day before. Colour bookings should carry one question: when did we last test you, and with what. If the answer is "never", "more than six months ago", or "you have changed my brand since", the colour appointment does not get confirmed until a test is booked.

Make the test a bookable service. Give it a name, a duration of 10 or 15 minutes and a price of zero, then let clients book it themselves. In Setora that is just another service on your Booking Page, bookable online like anything else. It sounds small. It is the difference between "ring us and we'll sort something" and a test that lands in the diary while the client is still thinking about their hair.

Book the test and the colour together. Take the colour slot at the same time, with the test at least two days before it. A client who has already got the colour appointment in their calendar turns up for the test.

Put the date where you will see it. The test date, product and result belong on the client record, next to their visit history. Ours is a plain client record with full history, not a compliance tool, and the signed record card is still your responsibility. Whatever you use, the rule is the same: the date has to be somewhere the person booking the appointment will actually look.

Remind, then protect. A reminder before the test appointment is worth as much as one before the colour appointment, because the test is the one clients treat as optional. Email reminders are included in Setora at £39/month per location, and SMS runs on credits on top. For clients who have already cost you a colour slot, a deposit on the colour booking does the rest. Our guide on when to send appointment reminders covers the timing evidence, and it holds for salons as well as shops.

Have a plan for the slot you lose. Someone will still turn up untested. Do not colour them, because that is exactly the moment the insurance question gets asked. Do the test there and then, rebook the colour, and put the empty slot to your waitlist while the client is still at the desk.

What you have to keep, and for how long

The record is not admin. It is the thing your insurer asks for.

For each test you should record whether a test was needed, the date, the product or brand, the result and whether the service can go ahead. Both you and the client sign or initial the client record card. Where you have given the client instructions to follow at home, record that too, with their signature confirming they will follow them.

For bleaching and lightening, recognised industry tests are needed before every service, for new and existing clients alike. NHBF guidance for the insurance it arranges says written test records should be kept for at least six years, each signed by the client.

Be honest about the limit of any booking system here, including ours. Setora holds services, appointments, client records and visit history. It does not have a patch test flag, consultation forms or signature capture, so it will not chase an expiring test for you. Some salon platforms do more on this: Phorest, for example, has been reported to integrate with Colourstart to prompt clients with no test history. If automated test tracking is the single thing your salon most needs, weigh that properly, and ask any vendor to show you the screen rather than the brochure.

Where to start this week

Pull your colour clients' last test dates. Anyone past six months, or on a brand you have changed since, needs a test before their next colour appointment. Then add the test to your bookable services, put one line on your booking confirmations, and tell your front desk to ask the question at the point of booking rather than the night before.

If your current system makes that harder than it should be, Setora is £39/month per location, no commission on bookings, and there is a 14-day free trial with no card required. Have a look at salon booking software and see whether the diary side of this gets easier.

Frequently asked questions

How long before a colour appointment does a patch test need to be done? At least 48 hours. The NHBF's position is that an allergy alert test should be carried out at least 48 hours before the service, because a reaction can take up to 48 hours to appear. How far in advance you can go is set by the manufacturer's instructions, so check them.

Do salons have to patch test every six months? Not exactly. Manufacturer instructions for many hair dyes ask for a test before every use. The salon protocol uses a questionnaire so a returning client on the same product and shade can be tested every six months instead, as long as the questionnaire says it is safe. If you are in any doubt, follow the manufacturer's instructions.

Is a patch test a legal requirement in the UK? No single law names patch tests. What binds you is the general duty in section 3 of the Health and Safety at Work etc. Act 1974, the UK Cosmetics Regulation requirement that hair dyes carry and are used according to their safety warnings, your insurance policy conditions, and ordinary negligence liability. In practice that combination makes testing non-optional.

Can a client do the patch test at home? Only with a product designed for it. The harmonised professional protocol recognises universal allergy screening tests licensed as medicines, such as Colourstart, which clients use themselves. It specifically does not recommend decanting colourant from its original packaging and posting it to clients, and warns that doing so may invalidate your insurance.

What should we record after a patch test? Whether a test was needed, the date, the product or brand used, the result, and whether the service can go ahead. Both you and the client should sign or initial the client record card. NHBF guidance for the insurance it arranges says written test records should be kept for at least six years.

Can we charge a client who skipped their patch test? You can apply your normal late-cancellation terms if the client had clear notice and agreed to them at booking. Any charge has to reflect what the missed booking actually cost you, and you need to have tried to refill the slot. Tell people at the point of booking that no test means no colour, and most of this problem disappears.

Sources

All links checked 6 August 2026. This guide is general information, not legal or insurance advice. Your manufacturer's instructions and your own policy wording come first.

Salon Patch Test Rules: The 48-Hour Guide for UK Hair Salons