Influencers are increasingly appealing to emotional narratives around health and often “fearmongering” to promote controversial medical tests on social media, according to a recent study. This trend is overwhelmingly misleading and fails to mention potential harms, the study found.

Published in the American Medical Association’s open access journal, the research investigated five tests being discussed on social media despite limited evidence of their benefits for generally healthy people and concerns about overdiagnosis. These tests include full-body magnetic resonance imaging (MRI) scans, genetic testing claiming to identify early signs of 50 cancers, blood tests for testosterone levels, the anti-Mullerian hormone (AMH) or “egg-timer” test, and the gut microbiome test.

The study analyzed 100 posts for each test on Instagram and TikTok respectively between April 2015 and January 2024. Excluding posts from accounts with fewer than 1,000 followers and in languages other than English, researchers analyzed the resulting 982 social media posts from account holders with more than 194 million total followers.

The study’s lead author found that posts about these tests came from a “wide range” of account holders, from major influencers to “everyday girl-next-door” accounts, as well as news outlets, doctors, and the companies making the tests. “Across the board, they were being promoted misleadingly,” she said.

These tests carry the potential for healthy people to receive unnecessary diagnoses, which could lead to unnecessary medical treatments or impact mental health.

The tests were promoted under the guise of empowerment: early screening as a way for people to take control of their own health. However, as Dr. Brooke Nickel noted, these tests carry the potential for healthy people to receive unnecessary diagnoses, which could lead to unnecessary medical treatments or impact mental health.

Nickel was struck by the “really personal narratives” being used: “Fearmongering that if you don’t do this test, you’re not taking care of your own health.” For example, despite the science of the gut microbiome test being in its very early stages, an Instagram account with over 65,000 followers promoted the test to its followers, telling them: “You DESERVE to be healthy. It is your BIRTHRIGHT. These tests will let us know with CERTAINTY what is causing your specific health concerns.”

Researchers found that the overwhelming majority of posts (87.1%) mentioned benefits of the tests, with harms mentioned by less than 15% of posts, and only 6% mentioned overdiagnosis or overuse. A promotional tone was used in 83.8% of posts – more than half (50.7%) encouraged viewers to take action and get the test, and 68% of account holders had financial interests involved.

Posts from doctors were more likely to mention harms and less likely to have an overall promotional tone, but Nickel said in some cases they were also “really strongly promoting the test.” One medical doctor with more than 65,000 followers on TikTok promoted the multi-cancer early detection test to their followers, telling them: “As you get older the chance of cancer is pretty high, if you do this test yearly then you’ll pretty much catch cancer early.”

The harms of cancer overdiagnosis were most clear, Nickel said, with both the full-body MRI and multi-cancer early detection test promoted as a way to identify early forms of cancer. Overdiagnosis refers to the diagnosis of very early forms of disease that are unlikely to cause any symptoms or problems but knowledge of which can do more harm than good, leading to psychological stress and unnecessary treatments including major surgery.

In addition to concerns about overdiagnosis, there were the financial costs of the tests themselves (full-body MRIs cost upwards of $800 in the U.S.) and of costly interventions pursued as a result. Despite egg-timer tests being unable to reliably predict a woman’s chance of conceiving, Nickel said there were concerns women who received low results may experience unnecessary anxiety, and go down the path of elective egg freezing or IVF interventions when they may not have been needed.

Nickel said the test “preys on the insecurity” of women regarding their future capacity to conceive, noting it was often promoted to younger women who might be years away from the decision. A medical doctor with more than 70,000 TikTok followers promoted the test: “Whether you’re in your teens or 30s, empowering yourself with fertility knowledge is extremely important. For women, age is not a friend.”

The testosterone test was most closely linked to promotion of treatments or supplements, and often carried “really clear narratives around masculinity,” Nickel said. A TikTok account with close to 100,000 followers promoted the testosterone test by telling followers: “Watch out for this scary sign of low testosterone levels … You should be waking up in the morning with a boner. If you’re not waking up in the morning with a boner there’s a large possibility you have a low testosterone level. Get it checked!”

Nickel said there were also potential dangers for men taking some testosterone supplements because of a lack of long-term evidence around safety. She said the problem overall was that because these tests were often sold direct to consumers, they “take the middle man – the doctor – out of the equation” and the space for a person to discuss with a medical professional whether they need the test or not.

This study adds to the evidence that medical misinformation is common on social media, and suggests we should all think again when an influencer encourages us to get tested.

Prof. Stacy Carter, the director of the Australian Centre for Health Engagement, Evidence and Values at the University of Wollongong, said the study used robust methods and “shows clearly that influential social media posts promote testing and talk up the alleged benefits of testing – even when tests are useless, or potentially harmful.”

Nickel said stronger regulation was needed so that the onus was not on individuals to see through the misinformation. The study highlights the need for greater scrutiny and regulation of medical information shared on social media platforms. As social media continues to influence public health decisions, it is crucial for consumers to be critical and seek professional medical advice before undergoing any tests or treatments.

This article was amended on February 27, 2025. Accounts with fewer than 1,000, not “100,” followers were excluded from the study.