Kim Kardashian endorsed the HiSmile teeth whitening brand, which went viral on Tik Tok, is subject to negative customer reviews – saying purple toothpaste ‘didn’t work’ or ‘products didn’t arrive’

As global marketing campaigns go, letting Kim Kardashian create a TikTok tidal wave of hype is probably as good as it gets.

Australian teeth whitening brand HiSmile, also known as “purple shampoo for teeth”, posted a video on its own TikTok page earlier this year featuring the American reality star.

The clip was seen by 21.6 million people, and Kardashian told followers she was “obsessed” with the brand’s V34 foam product, which HiSmile says “neutralizes yellow tones on the surface of the teeth.”

The star was reportedly paid up to £500,000 ($640,000) for a single sponsored Instagram post.

Based on Queensland’s Gold Coast, the teeth-whitening company has since seen its products – including fruity pastes, powders, serums and strips – fly off the shelves in UK branches of Boots and Superdrug, as well as online via Amazon and its own website.

@newhorizontwins replicated the dabs of the front teeth seen in the glossy ads for HiSmile, which have seen the toothpaste, powders and strips go viral but not get the same results, he says

A 30ml jar of the V34 jar promoted by Kardashian currently costs £19 at Boots or £15.20 on the HiSmile website – plus £4.99 delivery.

How does it claim to work? The brand’s signature V34 toothpaste contains the active ingredient Phthalimido Peroxy Caproic Acid (PAP) which, when oxidized, helps to break down stains and lighten the appearance of teeth.

The peroxide works by releasing molecules known as free radicals that convert the color of discolored tooth enamel to clear.

There are thousands of positive reviews on the product – including on both the Boots website and the review website Trustpilot – and celebrities such as Rita Ora, Rosie Huntington-Whitely, Millie Bobby Brown and Lily Allen all have glowing reviews.

In a video promoted on HiSmile’s own TikTok page, seen by 21.6 million people, Kim Kardashian said she was “obsessed” with the V34 foam product. Other celebrities who have been photographed with the product or recommended it on social media include Rita Ora, Rosie Huntington-Whitely, Millie Bobby Brown and Lily Allen.

In recent months, however, there seems to be a growing group of negativity surrounding HiSmile, focused on both the effectiveness of the product and customers reporting delivery delays.

The social media platforms that originally made the product so popular are now at least offsetting some of that heavy marketing investment, it seems — with TikTok dentists and product reviewers putting a less positive spin on the best-selling purple serum and the other products from HiSmile.

One half of TikToker @newhorizontwins revealed that he couldn’t tell a difference after trying the toothpaste. The social media star, who has 1.8 million followers on the account he shares with his twin brother, replicated the front teeth seen in the glossy ads for HiSmile, but didn’t get the same results, he says.

He told his followers that while he would give the paste the benefit of the doubt, the glowing white tooth seen in the ads didn’t work out for him.

HiSmile, the Australian teeth whitening brand, claims their V34 foam can “color” teeth in the same way purple shampoo helps reduce brassy hair tones. The product, now available in Boots, “also neutralizes yellow tones on the tooth surface,” the company adds. But it also offers a separate range of flavored toothpastes from £6 in watermelon, mango sorbet and peach iced tea flavours.

The British Dental Association said effective teeth whitening is best sought in a dental office and not with over-the-counter products

HOW DOES HISMILE’S BEST-SELLING V34 PRODUCT WORK?

The brand’s signature V34 toothpaste contains the active ingredient Phthalimido Peroxy Caproic Acid (PAP) which, when oxidized, helps to break down stains and lighten the appearance of teeth.

The peroxide works by releasing molecules known as free radicals that convert the color of discolored tooth enamel to clear.

A UK user who posted the latest move on TrustPilot offered just one star and said, “Please, please don’t waste your money on these products!” I bought a whitening toothpaste and it did absolutely nothing.’

Another Brit posted on the review site saying: ‘I was taken by all the great reviews, paid my money when I arrived couldn’t wait to try it, then absolutely no difference tried for two weeks to give it a good try , but still no difference please don’t waste your money.’

And another this week dealt with a seemingly shoddy delivery service and said, “Companies may face difficulties scaling. But this is just ridiculous. Do not expect any form of support from them regarding your order or any other questions.’

MailOnline spoke to the British Dental Association about whitening products in general.

The BDA has long campaigned for teeth whitening to ‘remain the practice of dentistry to ensure patients are protected’.

The organization said: ‘Dangerous levels of hydrogen peroxide are the equivalent of brushing with bleach and can endanger oral health.

‘Trading standards try to regulate the flow of these products onto our shelves, but it’s a mammoth task and some online products sold in the UK have been found to contain dangerous chemicals, which are either toxic or banned, and can seriously burn your gums . and damage your teeth.’

Eddie Crouch, president of the British Dental Association, told MailOnline: ‘At best people just waste money buying over the counter and online products to get whiter teeth.

“Worst-case scenario, you could end up on the receiving end of toxic or banned chemicals, which can damage your teeth and severely burn your gums.” Visit your dentist for safe and effective whitening.’

MailOnline has contacted HiSmile for comment.