Tooth whitening products that could harm teeth are a little harder to buy online, thanks to the efforts of Which?, a British consumer watchdog group.

The group discovered teeth whiteners available on major websites such as eBay, Amazon and Google that contain dangerously high levels of hydrogen peroxide – up to 350 times what is now permitted in the European Union.

It’s not just remarkable how much peroxide is in these products – it’s also remarkable how little peroxide is now permitted in whiteners sold in Europe. The European Union has recently banned sales of teeth whitening products with over 0.1% hydrogen peroxide. Here’s a brief history:

• March 2005: European Scientific Committee on Consumer Products (SCCP) recommends that >0.1 to 6.0% hydrogen peroxide (or equivalent for hydrogen peroxide-releasing substances) be considered safe “after consultation with and approval of the consumer’s dentist.”
• January 2008: SCCP again recommends that up to 6% hydrogen peroxide is a safe limit to use for at-home tooth bleaching.
• March 2010: The European Commission classifies over-the-counter tooth whitening products as cosmetics, not medical devices. As such, they are limited to containing or releasing a maximum of 0.1% hydrogen peroxide. (Read more)

By contrast, the home bleaching products that have the ADA Seal of Acceptance contain 10 percent carbamide peroxide (a bleaching agent that is roughly three times weaker than hydrogen peroxide).

We did a search in Google’s Shopping section for the term “carbamide peroxide,” and the very first result was a 44% carbamide peroxide solution available through Amazon. “There is no stronger or more effective gel available on the market,” reads the product description.

Other products that showed up in Google include:

• Four Patient 35% Hydrogen Peroxide Kit: 8-Arch
• 14% Hydrogen Peroxide Take Home Whitening Kit
•  Prefilled Whitening Tray 12% Peroxide
• Zoom Whitening Z Mint 6%
• 15 Syringes of 30% Carbamide Peroxide Gel
• 12 Syringes of 30% Hi-Intensity Carbamide Peroxide Gel
• Teeth Whitening Pens 44% Carbamide Peroxide (1000 Units)

Now, it seems unlikely that a consumer would drop $2,659 on 1,000 whitening pens, but that’s not the point. The point is that extremely powerful teeth whitening agents – the kind that should only be used by a licensed dentist – are easily available to the general public.

The products in question aren’t being sold directly by Amazon or Google, but by individual sellers who list their items on these sites. Policing the items available for sale on their sites is a real challenge for online marketplaces, but it’s also an important duty.

This was made dramatically clear in 1999 when a human kidney popped up on eBay. Though the site already had a policy that banned the sale of human organs, the kidney listing somehow made it past eBay’s security systems. Bidding reached over $5 million before eBay discovered it and ended the auction.

So what do you think?

On the one hand, consumers shouldn’t be using high-concentration bleaching products all by themselves. But on the other hand, the EU limit of 0.1% is incredibly low. Where is the happy medium?