What Is Methylene Blue and Can It Really Boost Your Brain?

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On May 13, 2025

Earlier this year, a video on YouTube of Robert F. Kennedy Jr. mixing a bright blue liquid into his drinking water midflight lit up social media.

Almost immediately, scientists and curious viewers speculated that the Health and Human Services Secretary was taking methylene blue, a century-old synthetic chemical that’s been used as a fabric dye, fish tank disinfectant, and blood disorder treatment. Recently, the chemical has gained popularity among wellness influencers on TikTok and biohackers as a brain health cure-all, mood and energy booster, and longevity promoter.

Experts, however, say it’s not a great idea to hop on the #bluetongue bandwagon just yet.

What Is Methylene Blue?

Methylene blue is a synthetic dye first developed in the late 1800s to stain fabrics. By the early 20th century, doctors began to use it as one of the first chemotherapies and as a treatment for malaria, says Jamie Alan, PharmD, PhD, a pharmacologist at Michigan State University in East Lansing.

“Although it was effective in malaria, it has been largely replaced by other therapies,” says Dr. Alan.

Today, methylene blue is approved by the U.S. Food and Drug Administration to treat methemoglobinemia, which is a rare disease that limits the oxygen-carrying capacity of our blood cells, she says. Methemoglobinemia can cause anemia and in extreme cases, death.

Gynecologists also use methylene blue to check for fallopian tube blockages during laparoscopic surgery.

Why Do Some Wellness Influencers Use Methylene Blue?

Methylene blue users say that putting a few drops of the chemical in their water improves memory, cognition, sleep, skin aging, energy, and longevity.

Most studies of methylene blue have been conducted in the lab in petri dishes or animal models — not in humans. While some laboratory studies have suggested methylene blue may improve mitochondrial function, the results have been mixed.

Mitochondria are the cells’ energy converters, and they are essential to many cellular processes. Many experts believe that malfunctioning mitochondria may contribute to diseases like Parkinson’s, heart disease, diabetes, and cancer.

What’s the Evidence for Methylene Blue?

“There is not solid data on how methylene blue would work off-label for something like cognitive function,” says Alan.

In fact, there are no clinical trials that demonstrate that the chemical leads to any improvements in brain function, sleep, aging, or energy.

There have been some lab studies to suggest that, in petri dishes, a methylene-blue-like chemical may have a positive effect on the clusters of proteins that develop in the brains of people with Alzheimer’s. Animal studies and a few small trials suggest there might be potential for methylene blue to help with other cognitive disorders as well — but there are still major concerns about safety and side effects.

Why Experts Think Taking Methylene Blue Is Risky

Methylene blue can be prescribed off-label for a variety of purposes, including vasoplegic syndrome (a type of shock that can happen during heart procedures), Lyme disease, and as an add-on to cancer therapy.

But physicians are concerned about people medicating themselves with methylene blue. “I do not recommend that anyone use methylene blue on their own. It should only be used under the supervision of a healthcare provider,” she says.

There are significant risks to taking methylene blue, says Alan, including:

Central Nervous System Symptoms Because methylene blue can cross into the brain, it can cause central nervous side effects such as dizziness, confusion, and headache.
Serotonin Syndrome Methylene blue interacts with several antidepressant drugs, and the combination can potentially lead to serotonin syndrome, a serious drug reaction caused by high levels of serotonin in the body. Symptoms include tremors, insomnia, confusion, and diarrhea. “It’s quite unpleasant while it is happening,” says Alan.
Kidney Damage Patients with poor kidney function should be especially cautious about using this compound.

Methylene blue also changes the color of a person’s urine to a blue-green color, although this is technically harmless, says Alan.

Bottom Line: Any Potential Benefits of Methylene Blue Aren’t Worth the Risk

Alan says any potential benefits of methylene blue are not worth putting your health at risk.

It’s also important to recognize that many people talking about the chemical on social media may not be completely familiar with the data, she says. “This is why healthcare professionals, not celebrities or politicians, should be the experts people seek when deciding whether or not to try the ‘latest and greatest’ trend.”