Is Teeth Whitening Safe? What the Law Says in the UK

Clinically reviewed by Dr Shaheen Alghofari, GDC-registered dentist (GDC no. 318372) at Twilight Dental, Leeds. Thinking about whitening? See dentist-prescribed teeth whitening in Leeds.

Who can legally whiten teeth in the UK?

Under UK cosmetic products law, tooth whitening products containing more than 0.1% and up to 6% hydrogen peroxide (or the equivalent in carbamide peroxide) can only be made available through a registered dental professional. The first treatment must be carried out by a dentist, or under their direct supervision, after an examination. These products must not be used on anyone under 18, except to treat disease.

The General Dental Council treats tooth whitening as the practice of dentistry. That means whitening by beauticians, salons, kiosks or mobile “technicians” is illegal, however professional it looks.

Why does that matter?

An examination first checks for decay, leaking fillings, gum disease and worn enamel, all of which whitening can make painful. It also identifies why your teeth are discoloured. Some staining is from coffee, tea, red wine or smoking and responds well. Some is from a dead tooth, old fillings or medication and needs a different approach. Illegal whitening often uses badly fitting trays, unknown products or acids that can burn gums and damage enamel.

What about shop-bought kits and strips?

Over-the-counter products in the UK are limited to very low peroxide levels, so many achieve little beyond surface stain removal. Some products sold online claim to be stronger or are “peroxide free” and rely on acids or abrasives. Charcoal powders can be abrasive and wear enamel over time. If a product seems too strong to be legal, it probably is.

Is dentist-prescribed whitening safe?

Yes. Professional whitening has a long safety record. At-home whitening with custom-made trays is the approach most dentists recommend: the trays are made from a scan or impressions of your teeth so the gel stays on the teeth and off the gums. You wear them for a set time each day or overnight for a couple of weeks, and can top up occasionally afterwards.

Side effects: sensitivity and gums

• Sensitivity is the most common side effect. It is usually mild and fades within a day or two of stopping. Sensitivity toothpaste, shorter wear times or a break between sessions help.
• Gum irritation can happen if gel gets on the gums. Well-fitting trays and the right amount of gel prevent most of this.

Whitening does not damage healthy enamel when used as prescribed.

Will whitening work on my crowns or veneers?

No. Whitening only changes the colour of natural teeth. Crowns, veneers, bridges and tooth-coloured fillings stay the same shade, so if you are planning new veneers or bonding, whitening is usually done first so they can be matched to your new shade.

How long do the results last?

Results commonly last a year or more, depending on diet and habits. Coffee, tea, red wine and smoking bring staining back faster. Occasional top-up sessions using your existing trays keep teeth bright, and our Whitening Maintenance membership plan is designed for this.

Getting started in Leeds

At Twilight Dental in Woodhouse, LS6 every whitening course starts with a £24 consultation (until 10pm) to check your teeth are healthy and give you a realistic idea of the shade you can reach. Evening appointments are available seven days a week.