Illegal teeth-whitening products widely available on online marketplaces, Which? warns

Which? is warning that a teeth-whitening craze driven by social media users could be leading people to buy products from online marketplaces with illegal levels of hydrogen peroxide, which can burn gums and cause permanent damage to teeth. 

The consumer champion’s latest investigation uncovered strips, gel-filled syringes and pens with brush tips that were dangerously overloaded with one of the active ingredients used for teeth whitening – yet these products were readily available to UK consumers on online marketplaces via third-party sellers on their sites. 

Worryingly 21 of the 36 teeth whiteners available on online marketplaces that were tested in the lab exceeded the legal amount of hydrogen peroxide permitted for home use.

The worst offender – teeth-whitening syringes sold on AliExpress – had more than 300 times too much hydrogen peroxide. Users of this product, costing just 85p per application, would be at particular risk of serious harm.

Teeth-whitening products sold over the counter should legally only contain up 0.1% hydrogen peroxide, while the legal limit for application by professional dentists is six per cent. However, many of the products Which? tested exceeded these levels by a significant margin.  

This is particularly concerning given Which? has also seen evidence of social media users encouraging followers to apply products with high levels of hydrogen peroxide at home. 

In one example, a woman told followers on TikTok she bought a bottle of three per cent hydrogen peroxide on eBay for £4 and applied it to her teeth. The video has received more than 20 million views. In this particular case the item wasn’t even marketed as a teeth-whitening product, so no laws would have been breached.  

In Which?’s tests the six most dangerous whiteners had more than 100 times too much hydrogen peroxide to be legally sold.

Five of these products were purchased from AliExpress. The worst one, a ‘Teeth bleaching gel kit’ sold by Oral Orthodontic Materials store, contained 30.7% hydrogen peroxide. 

Despite Crest Whitestrips not being officially sold in the UK, Which? found them being sold through a China-based Wish seller willing to ship to the UK. In lab tests, the strips were found to contain more than 132 times the legal amount of hydrogen peroxide. Procter & Gamble, owner of the Crest brand, told Which? that it doesn’t sell this product in the UK or Europe, as the law doesn’t permit its sale there. 

Overall, of the eight whitening products Which? bought from AliExpress, seven had too much hydrogen peroxide to be legally sold in the UK. For Wish, four out of six breached legal limits. 

Five out of nine of the products tested from eBay broke the law on hydrogen peroxide levels – the worst one contained 7.43%.  

Five out of 13 of the products tested on Amazon Marketplace had illegal amounts of hydrogen peroxide – the worst offender was a pen containing 7.87% of the chemical. 

Which? also tested a whitening kit available over the counter from high street retailers that contained legal and safe amounts of hydrogen peroxide. The Beverly Hills professional 2 in 1 whitening kit (£25), which is available from Lloyds Pharmacy and Superdrug, comprises a whitening pen and whitening strips. 

All of the online marketplaces removed the unsafe products that went above legal limits from sale when they were flagged to them by Which?. 

Which? advises consumers to seek help from a professional dentist if they are looking to get whiter teeth. Failing that, people should look to buy teeth whitening kits from a reputable high street retailer, as the legal responsibilities to ensure products are safe are stronger than on online marketplaces.

For any products that come with a gel formula, it’s worth getting a custom-made mouth tray that’s tailored to your teeth and mouth to minimise the risk of swallowing or gum damage.

Which? believes these findings raise further question marks over the checks and monitoring carried out by online marketplaces. 

The consumer champion is calling for the government to give online marketplaces legal responsibility for the safety of products sold on their sites. Until then, these platforms need to enhance their checks before including sellers on their sites, and take strong action against those who break the law through selling dangerous products. 

Which? has shared its findings with the Office for Product Safety and Standards (OPSS) for further investigation. Which? wants to see the OPSS urgently address these gaps in legal responsibilities as part of its review of product safety – and in the meantime, it should make sure marketplaces remove illegal products from sale as quickly as possible and ensure they do not reappear.

Sue Davies, Head of Consumer Protection Policy at Which?, said:

“It’s worrying that our tests have revealed so many of these products sold on online marketplaces – and often hyped on social media – are breaking legal limits for hydrogen peroxide and putting the health of users at risk. 

“It’s clear that self-regulation is not working, leaving people exposed to a flood of unsafe products online. It is absolutely crucial that online marketplaces are given greater legal responsibility for the safety of products sold on their sites, so that shoppers are far better protected from dangerous and illegal items.”

Notes to editors

The six products with more than 100 times the legal limit for hydrogen peroxide sold over the counter:

  • Teeth bleaching gel kit – 30.7% hydrogen peroxide, from Oral Orthodontic Materials store on AliExpress

  • Sunup teeth whitening gel – 29.7% hydrogen peroxide, from Expsmile store on AliExpress

  • Teeth whitening gel -14.3% hydrogen peroxide, from ZZ Shiny official store on AliExpress

  • Pro teeth whitening gel – 13.9% hydrogen peroxide, from BMT store on AliExpress

  • Crest 3D Whitestrips – 13.2% hydrogen peroxide, from Yougo flagship store on Wish

  • Professional bleaching kit – 10.6% hydrogen peroxide, from Dear Beauty Official store on AliExpress

Teeth whiteners on test


Number tested

Legal amounts of hydrogen peroxide 

No hydrogen peroxide found 

Illegal amounts of hydrogen peroxide





















High street brands










Rights of reply


“We take product safety very seriously and after being notified by Which? of its findings, we took prompt action and removed the third-party product listings identified to be in violation of our listing policy.

“We are a third-party marketplace and all merchants selling on AliExpress must comply with our platform rules and policies, as well as comply with all local laws and regulations. We will take action against sellers that are found to be in violation of our terms.”


“Safety is a top priority at Amazon and we want customers to shop with confidence. We require all products offered in our store to comply with applicable laws and we monitor the products sold in our stores for product safety concerns. When appropriate, we remove a product from the store, reach out to sellers, manufacturers, and government agencies for additional information, or take other actions.

“If customers have concerns about an item they’ve purchased, we encourage them to contact our Customer Service directly so we can investigate and take appropriate action. The products in question have been removed.”


An eBay spokesman said: “We take the safety of our users extremely seriously and work closely with authorities including Trading Standards to help ensure sellers and listings on eBay comply with laws and regulations. We have removed five of the nine listings tested by Which? and taken the appropriate action on the sellers.

“We have filters in places which automatically block listings which are unsafe or do not comply with our policies. These blocked six million unsafe listings from making it onto site in 2020. Our teams also work around the clock as an additional safety net to manually review and remove anything which may not have been caught by our filters.”


Wish told Which? that its internal teams looked into the items identified and confirmed that all four listings had been taken down.

Oral Orthodontic Materials store

Oral Orthodontic Materials store told Which? that it found the mistake, corrected it in time and that the product has been removed from sale.

Procter & Gamble

Procter & Gamble, owner of the Crest brand, told Which? that it doesn’t sell this product in the UK or Europe, as the law doesn’t permit its sale there. But it does sell a version of the product with the permitted amounts in Europe through dentists.

Procter & Gamble told Which?: “Any European site supplying Crest Whitestrips isn’t supported by us and we will challenge those sites selling outside the territory they were designed for.”

Expsmile store, ZZ Shiny official store, BMT store, Yougo flagship store and Dear Beauty Official store

Which? reached out to these sellers for comment but had not received a response by the time of publication.

Sunup teeth whitening gel and the Professional Bleaching Kit

Which? contacted the manufacturers of the Sunup teeth whitening gel and the Professional Bleaching Kit but had not received a response by the time of publication. 

Other manufacturers

Which? was unable to ascertain who manufactured the other teeth whitening products featured.

About Which?

Which? is the UK’s consumer champion, here to make life simpler, fairer and safer for everyone. Our research gets to the heart of consumer issues, our advice is impartial, and our rigorous product tests lead to expert recommendations. We’re the independent consumer voice that influences politicians and lawmakers, investigates, holds businesses to account and makes change happen. As an organisation we’re not for profit and all for making consumers more powerful.

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