Online teeth whitening kits are easy to find, from whitening strips and LED kits to gels advertised on social media. But how can you tell whether a product is safe to use? New UK investigations have found whitening products being offered at concentrations far above the limits for direct consumer sale.
We first wrote about the risks in our 2021 warning on buying teeth whitening kits online. Rather than replace that article, we wanted to share the more recent findings and explain how they affect anyone considering teeth whitening at home in Kingston or elsewhere in the UK.
A helpful place to start
Not every online whitening kit is unsafe — but being for sale does not mean a product is legal or suitable for your teeth.
A quick check of the ingredients, seller and your oral health can help you avoid unnecessary risks. A dentist can also explain how professionally supervised home whitening works.
Jump to: New evidence · UK legal limits · Safer options
45 / 70
Targeted products above the consumer-sale limit in UK government testing
53%
Hydrogen peroxide found in a gel during the BBC’s investigation
0.1%
Maximum hydrogen peroxide permitted for direct consumer sale
The 70 products were selected for targeted regulatory testing. These results must not be interpreted as the proportion of all online whitening kits that are non-compliant.
In its 2025–2026 Delivery Report, published on 5 August 2026, the Office for Product Safety and Standards (OPSS) described a targeted laboratory assessment of 70 teeth whitening products. It found that 45 exceeded the 0.1% hydrogen peroxide limit for products sold directly to consumers.
The report also describes enforcement activity that resulted in seizures of imported teeth whitening goods valued at more than £1 million. This shows that the regulator is continuing to investigate potentially non-compliant products, including those sold through online marketplaces.
What does “45 out of 70” actually mean?
These were targeted products chosen for investigation, not a random survey of everything available online. The findings are important evidence of non-compliance — they do not prove that most whitening kits sold online are illegal.
In October 2025, BBC North West Investigations reported on illegal teeth whitening products and treatments advertised through social media. Laboratory analysis of gels obtained by the BBC identified hydrogen peroxide concentrations of up to 53%.
The investigation also raised concerns about untrained providers and misleading training certificates. The British Dental Association warned of the risk of chemical burns, tooth damage and, in serious cases, tooth loss from inappropriate whitening treatment.
A product safety alert from September 2025
A whitening pen sold via eBay was found to contain 7.32% hydrogen peroxide and was classified by the UK government as presenting a serious chemical risk. The listing was removed and the product seized and destroyed.
Hydrogen peroxide is a bleaching agent used in many whitening treatments. Under UK cosmetic rules, the permitted concentration depends on who supplies the product and how it is used. The General Dental Council (GDC) explains the position.
Up to 0.1%
Direct consumer sale
May be sold directly to consumers, subject to other cosmetic safety requirements.
Above 0.1% – 6%
Dental professional use
Subject to professional restrictions, including first use by a dentist or under their direct supervision.
Above 6%
Not permitted
Not permitted for cosmetic teeth whitening in the UK.
Percentages refer to hydrogen peroxide present or released. Cosmetic whitening with products above 0.1% is generally restricted to adults, apart from a narrow exception for treatment or prevention of disease.
Teeth whitening is a form of dentistry. A beauty salon certificate or a short online course does not make somebody a GDC-registered dental professional. You can check whether someone is registered using the GDC online register.
Some whitening products are legally sold and used without difficulty. However, high-strength bleaching agents, poor instructions or whitening teeth that need treatment first can cause problems, including:
Temporary sensitivity or gum irritation can occur even with dentist-supervised whitening. The difference is that your dentist can assess your mouth beforehand, recommend an appropriate product and explain what to do if you experience problems.
Worth remembering: whitening only changes the shade of natural teeth
Crowns, veneers and white fillings will not whiten in the same way. If you have dental work at the front of your mouth, speak with your dentist about the likely result before starting treatment.
Words such as “natural”, “peroxide-free” or “dentist recommended” do not, on their own, prove that a product is safe or effective. If you are unsure, please ask your dentist.
Related reading · From our archive
Our original warning about online whitening kits
Read the 2021 post covering the earlier Which? investigation. It remains available alongside this updated guide, so you can see why the safety conversation has continued.
Read the original 2021 articleYes. Home whitening can be carried out with a dentist-prescribed system, which is different from purchasing an unverified kit from an online marketplace. The NHS guidance on teeth whitening describes whitening through a dentist as the safest approach.
At Thames Street Dental in Kingston upon Thames, we provide dentist-supervised home whitening using custom-fitted trays and professional whitening gel. Our dentists can explain the options, including Boutique Whitening and Enlighten, and whether teeth whitening is suitable for you.
1
Check suitability
Your dentist examines your teeth and gums and discusses your goals.
2
Prepare custom trays
Custom-fitted trays and an appropriate whitening gel are arranged.
3
Whiten with guidance
You follow your dentist’s instructions at home and can ask for advice.
Teeth whitening · Kingston upon Thames
Considering a brighter smile?
Book a consultation to check whether whitening is suitable and discuss dentist-supervised home whitening with our friendly team.
If a whitening product causes burning, severe sensitivity or significant irritation, stop using it immediately. Gently rinse your mouth with water and avoid applying more whitening chemicals. Keep the packaging and ingredient information if you can, as it may help your dentist understand what you have used.
When to seek help
Contact a dentist promptly for persistent pain, swelling, gum burns or pronounced sensitivity. If swelling affects your breathing or swallowing, seek emergency medical assistance.
No. Some online products can be sold legally if they meet the applicable rules. However, a product listed on a website is not automatically compliant, and products with hydrogen peroxide above the limit cannot be sold directly to consumers for cosmetic whitening.
An LED light does not establish that a kit is safe. The ingredients, concentration, instructions and suitability of your teeth and gums remain important. Be cautious about dramatic results promised by a product you cannot verify.
Not necessarily. “Peroxide-free” describes what a product claims not to contain; it is not an independent safety assessment. Read the ingredients and ask your dentist if you are unsure.
Whitening is intended to lighten natural teeth. Existing restorations generally do not respond in the same way, so your dentist may need to consider these when planning the final shade.
Possibly, but your dentist should assess the cause and severity first. Some forms of sensitivity need treatment before whitening, and your dentist can advise on suitability and ways to minimise discomfort.
Results vary with your starting tooth colour, habits, oral health and aftercare. For a more detailed explanation, read our article on how long teeth whitening lasts.
Safety · 2021
Think Twice Before Buying Teeth Whitening Kits Online
Our original guide, including the earlier Which? findings.
Safety · Background
Dangers of Unregulated Teeth Whitening
Why unregulated products and providers can be risky.
Patient guide
How to Whiten Teeth
Understanding stains, professional whitening and realistic results.
Patient guide
How Long Does Teeth Whitening Last?
What affects the longevity of results and how to maintain them.
The information in this guide is based on official UK safety and dental guidance, alongside the BBC investigation:
This article provides general information and is not a substitute for a dental examination or individual treatment advice.
At Thames Street Dental, we are an independent, family-run practice in the heart of Kingston upon Thames. We welcome patients from Kingston, Surbiton, Norbiton, Hampton Wick, Teddington, New Malden and nearby areas who want to explore their options for a brighter smile.
If you are considering teeth whitening, arrange an appointment so we can check your teeth and gums and talk through the most appropriate options for you.
Thames Street Dental · Kingston
Ready to explore safe teeth whitening?
Speak to our team about dentist-supervised home whitening, suitability and the results you can realistically expect.
28 Thames Street, Kingston upon Thames KT1 1PE
Prefer to talk? 020 8546 6546 · Contact us
020 8546 6546
