From TikTok tutorials to Instagram infographics, the pursuit of a sharper mind has fuelled a booming online market for so-called brain-boosting supplements. While influencers tout the benefits of fish oil, lion’s mane mushroom, and even a surgical dye, medical experts are issuing stark warnings about potential dangers and urging caution, emphasising that these products are no substitute for a healthy diet and are often backed by limited scientific evidence.
The wellness trend heavily promotes omega-3 fatty acids, essential nutrients found in fish that are linked to cell health, hormone production, and a reduced risk of heart disease and cancer. The National Institutes of Health notes that while generally safe, fish oil supplements can cause side effects like bad breath, headaches, and nausea, and federal officials recommend not exceeding five grams daily. More seriously, the Cleveland Clinic warns they can raise the risk of irregular heartbeat, stroke, and bleeding, and may interfere with medications.
While the Mayo Clinic states these supplements might be helpful for specific conditions like rheumatoid arthritis or high triglycerides, the overall research on their effectiveness is mixed. Crucially, as dietary supplements, they are not regulated by the U.S. Food and Drug Administration for safety or efficacy before they are sold. “Supplements are sometimes necessary while you transition to a healthy diet, but they do not replace it,” explained Dr. Daniel Monti of Jefferson Health.
Beyond Fish Oil: A Mushroom and a Tea Extract
The trend extends to other natural compounds. Lion’s mane mushroom, a white fungi promoted for memory and focus, is generally recognised as safe when eaten as food. However, less is known about its supplement form. The Memorial Sloan Kettering Cancer Center lists potential side effects including abdominal discomfort, nausea, and skin rash. Registered dietitian Jen Messer warned it “could pose risks for those taking blood thinners or immune-modulating prescriptions.”
Similarly, L-theanine, an amino acid from tea leaves said to improve mental clarity and alleviate stress, is considered safe at doses under 500 milligrams per day. The Cleveland Clinic advises it can still cause headaches, dizziness, nausea, and diarrhoea, and may interact with certain medications.
The Most Alarming Trend: Methylene Blue
The most concerning supplement gaining traction online is methylene blue. Touted on social media for eliminating brain fog and concussion symptoms, it is in fact a surgical dye and cyanide antidote with only one FDA-approved use: treating a blood disorder called methemoglobinemia.
Professor Lorne Hofseth of the University of South Carolina notes that most research suggesting cognitive benefits, such as improved learning and memory protection, comes from studies on rats. A 2023 study he highlighted found methylene blue decreased human brain blood flow by eight percent. The side effects can be severe, ranging from fever and upset stomach to more adverse reactions.
“Using it at high doses can raise blood pressure or cause heart problems,” experts warn, adding it can trigger a dangerous blood condition in people with a specific genetic enzyme deficiency. Furthermore, combining it with common antidepressants or anti-anxiety medication can lead to serotonin syndrome, a potentially life-threatening condition causing high fever, seizures, or death.
“Overall, while scientists have found hints of some fascinating properties of methylene blue, much larger, longer trials are needed to know if it truly works, what the right dose is and how safe it is over time,” said Professor Hofseth. The consensus among health authorities is clear: the unverified promises of brain health supplements carry significant risks, and their use should only ever be considered after consultation with a medical professional.
