Influencers are promoting “overwhelmingly” misleading information about medical tests on Instagram and TikTok, according to a global University of Sydney-led study published in JAMA Network Open.
Researchers analyzed almost 1,000 posts about five controversial medical screening tests that had been promoted by social media influencers to almost 200 million followers. They found most posts had no reference to scientific evidence, were promotional, had explicit financial interests, and failed to mention potential harms.
The tests included full-body MRI scans; genetic testing claiming to identify early signs of 50 cancers; blood tests for testosterone levels; the anti-mullerian hormone (AMH) test which surveys a woman’s egg count; and the gut microbiome test. Experts say these tests have limited evidence of benefit in healthy people and could lead to overdiagnosis and overuse.
“The vast majority of these posts were overwhelmingly misleading,” said Dr. Brooke Nickel, who led the research from the Faculty of Medicine and Health’s School of Public Health.
“They are being promoted under the guise of early screening, as a way to take control of your own health. The problem is they are unnecessary for most people and, in some cases, the science backing their efficacy is shaky,” Dr. Nickel said.
The study found 85% of the posts did not mention any test downsides or risks. “These tests carry the potential for healthy people to receive unnecessary diagnoses, which could lead to unnecessary medical treatments or impact mental health,” Dr. Nickel said.
“One example is the ‘egg timer’ or AMH test. It is being heavily marketed to women by influencers as a way of measuring fertility, but experts do not consider it to be reliable. There is the concern that a low result discovered outside the context of a specific medical issue may drive some women to unnecessary, costly fertility interventions,” she said.
“Another example is the testosterone test, often marketed to men using fear-mongering tactics to then promote testosterone supplements which claim to enhance masculinity and sexual performance. This is risky as the long-term safety of testosterone replacement therapy on cardiovascular health and mortality is still unknown.
“One of the underlying themes being used by influencers promoting these tests is that knowledge is power, but most information is cherry-picked. When it comes to health, getting the full picture is so important, and half-truths are often lies.”
Among the 982 posts on Instagram and TikTok:
– 87% mentioned the benefits of the tests, yet only 15% mentioned potential harms;
– Only 6% mentioned the risk of overdiagnosis or overtreatment;
– Only 6% mentioned scientific evidence, while 34% used personal anecdotes to promote the test;
– 68% of influencers and other account holders had financial interests in promoting the test (e.g. partnership, collaboration, sponsorship, or selling for own profit in some way).
Co-researcher Dr. Ray Moynihan, an Honorary Assistant Professor at Bond University, said, “These findings suggest social media is an open sewer of medical misinformation.
“This is a public health crisis that exacerbates overdiagnosis and threatens the sustainability of health systems.”
A detailed analysis of the results found that posts from medical doctors, posts mentioning scientific evidence, and posts from influencers with no financial interest in the tests tended to be more balanced overall.
The research group is currently investigating ways to better regulate this type of misleading medical information on social media.
“Given that social media platforms like Instagram are moving away from fact-checking their content, the need for stronger regulation to prevent misleading medical information has gained urgency,” said Dr. Josh Zadro, senior researcher, and co-author from the University of Sydney.
Five common controversial tests in Instagram and TikTok posts:
– Full-body MRI scan: Claimed to test for up to 500 conditions, yet no evidence of benefit for healthy people, while real dangers exist of unnecessary diagnoses and overtreatment.
– Multi-cancer early detection tests: Claimed to screen for more than 50 cancers, yet clinical trials are still underway. As yet, there is no evidence that the benefits of screening healthy populations will outweigh the harms of unnecessary cancer diagnoses.
– AMH or “egg-timer” test: While beneficial for certain women, this test is falsely promoted to healthy women as a test for fertility, with concerns the results can lead to unnecessary, costly fertility treatments.
– Gut microbiome test: Test promises “wellness” via early detection of many conditions—from flatulence to depression—without good evidence of benefit, alongside concerns that test results could lead to medical overuse, causing harm and waste.
– Testosterone test: No evidence of benefit for testing healthy men, yet the danger of overuse of treatments; long-term safety of testosterone therapy in relation to adverse cardiovascular events and early death has not yet been established.
More information:
Social Media Posts about Medical Tests with Potential for Overdiagnosis, JAMA Network Open (2025). DOI: 10.1001/jamanetworkopen.2024.61940
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