Brain supplements have become a social media wellness trend – but are they safe to take?

Omega-3 fatty acids are essential nutrients that keep the body’s cells healthy, trigger the production of happy hormones and help slash the risk of heart disease and cancer when consumed as a part of your daily diet.

On social media, boosting brain health has become a wellness trend – and influencers point to taking fish oil and other supplements as part of this, positing thousands of videos on TikTok and other platforms. Researchers have linked omega-3s in fish to improved cognition, according to the Cleveland Clinic.

But do supplements work and is it safe to take them every day? Experts stress that while some people can safely use these supplements after talking to a doctor, there may be some unexpected and dangerous side effects. And they are no replacement for a healthy diet, Jefferson Health Dr. Daniel Monti said.

“Supplements are sometimes necessary while you transition to a healthy diet, but they do not replace it,” he explained.

In fact, fish oil and other dietary supplements – which are not regulated by the U.S. Food and Drug Administration – may do more harm than good.

While generally safe, taking fish oil supplements can raise the risk of irregular heartbeat, stroke, bleeding and interfere with medications, according to the Cleveland Clinic.

They may also cause bad breath, bad-smelling sweat, a headache, heartburn, nausea and diarrhea, the National Institutes of Health says. Federal health officials recommend taking no more than five grams a day of the omega-3s found in fish.

The supplements might be helpful for people with rheumatoid arthritis or high levels of fats called triglycerides that raise your risk for heart disease, the Mayo Clinic says. But federal health authorities say the research about the effectiveness of fish oil is mixed.

That’s also the case regarding the efficacy of lion’s mane – another food-based supplement that social media users say aids memory and focus. Lion’s mane, a white fungi, is generally recognized as safe when consumed as food. But not a lot is known about what supplements do as studies have been limited.

Recorded side effects with lion’s mane include abdominal discomfort, nausea and a skin rash, according to the Memorial Sloane Kettering Cancer Center. The mushroom may also interact with certain medications.

“It could pose risks for those taking blood thinners or immune-modulating prescriptions,” Jen Messer, a registered dietitian and president of the New Hampshire Academy of Nutrition and Dietetics, told USA Today.

L-theanine can interact with medications, too. The amino acid that’s present in green and black tea leaves works to improve mental clarity and alertness. Social media users claim that taking L-theanine supplements can also alleviate stress.

It’s generally considered safe when people don’t take doses exceeding 500 milligrams a day – but there can be some uncomfortable side effects, such as headaches, dizziness, nausea, irritability, jitteriness and diarrhea, according to the Cleveland Clinic.

Taking methylene blue as a supplement can cause some of these symptoms, as well. On TikTok, users say it stimulates the brain, eliminates brain fog and has helped eliminate symptoms of a concussion.

But experts note that the surgical dye and cyanide antidote only has one FDA-approved use: to treat a blood disorder called methemoglobinemia.

And there isn’t enough evidence to say you should take it for improved brain health. Most related research has been done on rats, finding that it may improve the rodents’ learning, boost memory and protect brain cells, according to University of South Carolina professor Lorne Hofseth.

Taking methylene blue may lead to a fever, upset stomach and diarrhea. But it can have more adverse affects and be deadly, experts warn.

A 2023 study found that methylene blue decreased human brain blood flow by eight percent.

Using it at high doses can raise blood pressure or cause heart problems, and lead to a dangerous blood condition that causes an abnormally fast heart rate in people with a genetic deficiency of an enzyme called G6PD.

Taking antidepressants and anti-anxiety medication while using methylene blue can lead to a a life-threatening condition called serotonin syndrome that may lead to developing a high fever, having seizures or even 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 Hofseth.