‘Deepfake epidemic’: Doctor finds himself in AI-manipulated ad peddling food supplement
Dr. Karan Rajan said false health advertisements 'could lead to major harm'
When we have a medical issue, we usually turn to our doctors for trustworthy advice and help.
Increasingly, in the age of social media, an intermediary space has opened up: the influencer doctor. Millions of people turn to doctors who have made a career online to help answer questions about general health concerns.
One such medical professional is Dr. Karan Rajan, a British surgeon and university lecturer, who has built a huge following – 5.3m on TikTok and 1.7m on Instagram, to be precise – with his easy-to-digest educational videos about everything from diet and gut health to strange symptoms and periods.
Dr. Karan also reacts to circulating health-related videos, adding context and confirming – or debunking – the claims and issues social media users are reporting.
Given all this, it’s unsurprising that Dr. Karan has built a loyal follower base of people who trust his takes, and look to him for clarity amid the sea of health misinformation we have become used to online.
But earlier this week, Dr. Karan Rajan came online to share a different kind of video (archived here). He had become aware that a video of him advertising a product claiming to treat high cortisol was being pushed as an advertisement on TikTok.
Except it wasn’t him. It was an AI-altered deepfake, one which he had nothing to do with.
Deepfake drawn from a real podcast interview
In the advertisement run by ‘Healthy Life UK’, Dr. Karan was seen promoting a product for high cortisol. The account running the ad has since been removed, but Dr. Karan showed some of the clip in his reaction video.
The fake Dr. Karan can be seen explaining different symptoms of high cortisol, before saying that he recommended a Moringa Leaf supplement to treat it.
“Most people realise that Moringa has 23 times more iron than spinach, seven times more calcium than milk, 11 times more Vitamin A than carrots, 15 times more potassium than bananas, and nine times more protein than yoghurt. Moringa is a game-changer.”
The deepfake Dr. Karan then goes on to say: “A lack of essential vitamins is the main cause of health issues in the UK. And the solution? Just take two capsules of Moringa every day … Right now, they’re running a spring sale where you can get it for half the price.”
The ad included an onscreen link to the TikTok Shop, for users to click through and purchase the supplement, according to the screen-recording published by Dr. Karan Rajan. In his reaction video, he said the ad caused him to be “very concerned”.
“This kind of sounds like me and basically does look like me beyond some of the weird lip movements. And if you didn’t pick it, this is a deepfake. The science is completely wrong and those are words that I’ve never said.”
The doctor confirmed where the image of him, sitting in front of a purple background, really came from. It was a podcast appearance (archived here) posted in early 2023 in which he talked about endometriosis.
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False health ads ‘could lead to major harm’
Dr. Karan said: “This company, I think based in the UK, ran it through AI and digitally manipulated it to run ads. Unfortunately after asking them if they could stop using my likeness and my intellectual property for commercial use without my consent, which I believe is illegal, they just blocked me.”
Commenting on the potential impact of such ad campaigns, the doctor said: “This is very worrying, because someone who doesn’t follow me or know me might believe this to be a real advert. And if they think it’s coming from a doctor, they might be influenced to buy the product for a health reason. And if the product promoted is something untested, unregulated and dangerous, it could lead to major harm.”
Over on LinkedIn, the celebrity doctor called on TikTok to “do something urgently on the platform to stop this becoming the norm”.
TikTok’s advertising policies for healthcare-related products and services say that all health and pharmaceutical products must comply with local laws. For the UK (and several EU countries), that means over-the-counter medicines may be advertised as long as the advertiser has provided proof of “approval and certification from appropriate regional regulating authorities”. Cosmetic products must not make medical claims unless the uploader has an “approved medical license or certification”. The section about the UK rules in TikTok’s ad policy database does not make any specific reference to supplement-type products, as it does for some other countries.
The UK’s ad regulator, the Advertising Standards Authority, lists the rules around the promotion of food supplements. One of these rules is that “no marketing communication may suggest that a widespread vitamin or mineral deficiency exists”.
Given that the ad used the image and likeness of a well-known doctor, we were interested to look into the TikTok policies around deceptive advertising. TikTok says it does “not allow products and services that might expose, steal, or infringe upon individual privacy”.
“We also prohibit any unlawful activities, such as circumventing access restrictions, identity theft, document falsification, and making deceptive claims.”
TikTok in focus for failing to enforce ad rules
Despite the rules that TikTok has in place around advertising on its platform, alarm has been raised about a seemingly ‘wild west’ approach to enforcement on ads that breach rules.
In 2024, the Sydney Morning Herald newspaper reported on a spate of TikTok ads in the health/cosmetics space for tanning products that were reported to the Australian regulator for breaches of local advertising standards. Sun and tanning-related advertising is strictly regulated in Australia due to the country’s high skin cancer rates.
Meanwhile, an investigation carried out by Global Witness in 2024 saw the campaign group submitting ads targeting the Irish market to different social media platforms, all containing false information in the lead-up to the European parliamentary elections.
All 16 of the submitted ads were approved for publication. They were withdrawn by Global Witness before they could reach the public. TikTok said in response that all 16 of the ads violated TikTok’s advertising policies, and added that their systems “correctly identified that all these ads may violate our political ads policies”. They were sent onwards to a moderator for additional review, where TikTok said they were “approved due to human error”.
The experiment prompted Global Witness to file a complaint with the EU’s regulator.
The campaign group conducted a second go of the investigation when Ireland went to the polls for a general election in November 2024, finding: “TikTok approved more than half the election disinformation ads we submitted to them in Irish, and more than 20% of the election disinformation ads in English.”
SOURCES
Imperial College London. (2025). Dr Karan Rangarajan. [online] Available at: Alumni stories – Dr Karan Rangarajan [Accessed 17 Apr. 2025].
Instagram. (2025). Dr Karan Rajan (MRCS MBBS BSc) on Instagram: ‘The deepfake epidemic’. [online] [Accessed 17 Apr. 2025].
Tiktok.com. (2025). TikTok – Make Your Day. [online] Available at: ‘The deepfake crisis’ [Accessed 17 Apr. 2025].
Tiktok.com. (2025). TikTok – Make Your Day. [online] Available at: ‘Doctors are terrible at diagnosing this!’ [Accessed 17 Apr. 2025].
Tiktok.com. (2025). TikTok Ads Manager | Healthcare and Pharmaceuticals. [online] [Accessed 17 Apr. 2025].
Advertising Standards Authority | Committee of Advertising Practice (2020). Food, food supplements and associated health or nutrition claims. [online] Asa.org.uk. [Accessed 17 Apr. 2025].
Tiktok.com. (2025). Deceptive Practices | TikTok Advertising Policies. [online] [Accessed 17 Apr. 2025].
Dow, A. (2024). ‘Wild west’: The TikTok tanning ads breaching community standards. [online] The Sydney Morning Herald. [Accessed 17 Apr. 2025].
Global Witness. (2024). Ticked off: TikTok approves EU elections disinformation ads for publication in Ireland. [online]. [Accessed 17 Apr. 2025].
Global Witness. (2024). TikTok still approving election disinformation ads in Ireland. [online] [Accessed 17 Apr. 2025].