5 days ago
- Health
- National Geographic
What is methylene blue and can it really boost your brain power?
The trendy supplement was originally developed as a fabric dye—and later used as a malaria treatment. We asked experts if it really has the cognitive benefits touted on social media. A solution of methylene blue in an erlenmeyer flask. The trending dye was invented by German chemist Heinrich Caro in 1876. Photograph by asikkk, Getty Images
If you've spotted someone recently with a blue tongue, that inky stain could actually be the side effect of a new health trend.
Biohacking enthusiasts have been using a substance called methylene blue as a daily supplement, sharing videos of their stained tongues on TikTok. Users claim the highly pigmented compound, which was originally developed as a fabric dye before being used for medical purposes, can improve cognitive function, energy levels and mood, and could even prevent Alzheimer's disease.
But what do experts have to say? Here's what doctors and researchers say you need to know about potential effects of using methylene blue as a supplement.
The history of methylene blue dates back to the late 19th century, when it was synthesized as a textile dye.
The trending blue dye was invented in 1876 by German chemist Heinrich Caro. As he was searching for novel dyes for cotton derived from byproducts of the coal industry, one of his experiments accidentally created a vivid blue compound.
Methylene blue's chemical structure gives it its signature blue color. 'It absorbs photons of certain wavelengths and the blue photons are the only ones left to be reflected rather than absorbed by the molecule,' explains Dr Roger Rothenberg, assistant professor of clinical medicine at Temple University Hospital's Lewis Katz School of Medicine. In other words, it absorbs all the colors that make up the rainbow spectrum apart from blue, which is reflected back to our eyes, making it appear blue.
A decade after Caro's accidental invention, another German scientist, Paul Ehrlich, discovered during an experiment that the organic compound turned parasite cells blue under a microscope. One of the dye's most famous uses is identifying malaria cells and it was later administered in Germany, France and the UK as a treatment for the illness.
(To fight malaria, scientists want to poison mosquitoes—with human blood.)
'There was some efficacy for its use in malaria,' Rothenberg says, 'but not as much as the standard treatment for malaria at the time [quinine], so it fell out of favor for that purpose.' What is methylene blue used for?
Nowadays, the treatment of methemoglobinemia is methylene blue's only FDA-approved use.
Methemoglobinemia is a disorder in which red blood cells can't adequately deliver oxygen to the mitochondria, where it's needed for energy production, leading to symptoms including fatigue, dizziness and shortness of breath. In serious cases, it can be life-threatening.
Methylene blue is also still used as a stain in surgical or diagnostic procedures. Physicians have used the compound to help visualize the urinary tract or lymph nodes in colorectal cancer. Methylene blue may be given intravenously for the treatment of methemoglobinemia, a disorder that reduces the blood's ability to carry oxygen. Photograph by James Mutter, Gett Images Initially, methylene blue was initially used for dying textiles. As it turns out, methylene blue is also excellent for dying cell nuclei and cytoplasm, as well as nerve fibers such as the motor neuron above. Micrograph by Ed Reschke, Getty Images
Raphael E. Cuomo, scientist and professor at University of California, San Diego School of Medicine, says that as a supplement taken in low doses, methylene blue 'has the potential to enhance mood and energy, and possibly cognitive function, because it inhibits monamine oxidase and also has benefits on mitochondrial activity.' Monamine oxidase (MAO) is an enzyme which breaks down neurotransmitters like serotonin and dopamine. Allowing these feel-good chemicals to flow freely in theory creates a mood boost, while aiding the delivery of oxygen to mitochondria—the 'powerhouses' of cells, can result in more energy.
(How to get high on your own hormones—naturally.)
However, evidence for these effects in humans is limited, Rothenberg says. 'This is based entirely in theory, from studies on isolated tissue cultures and rats. There are maybe four to six randomized studies in human beings on this general cognition indication. That seems to be the reason people are taking it as a supplement.' For example, a 2021 study of 248 elderly adults found methylene blue administered intravenously significantly reduced postoperative cognitive disorders.
Claims that methylene blue can alleviate the symptoms of Alzheimer's disease may be more reasonable, Rothenberg believes. 'The few human studies were done on Alzheimer's patients. There was a statistically significant, though very small, effect of methylene blue in mild to moderate Alzheimer's disease, showing five points [of improvement] on a 70-point scale,' says Bronwyn Holmes. Holmes specializes in regenerative and longevity medicine and says the results should be interpreted with caution. 'A man and a woman who have Alzheimer's, or any neurological disease, they metabolize methylene blue differently, so [the effect may be] very different depending on the patient,' says Holmes. What experts say about oral methylene blue
Physicians are seeing the trend of methylene blue used as a supplement skyrocket, thanks in part to viral videos across social media. TikTok specifically is flooded with videos in which users rave about the latest nootropic, meaning a supplement with cognitive benefits. Holmes, who is on the Medical Advisory Board at healthcare provider Eden Health, says she first had patients asking her about the 'neurological benefits' of methylene blue around three years ago.
Some experts are skeptical about off-label use of methylene blue as a brain booster. 'Never has a patient come to me with perimenopausal or post-menopausal brain fog, taken methylene blue, and all of a sudden the brain fog has declined,' says Holmes. Rothenberg suggests, 'it's very hard to really prove or disprove these claims when you have individuals taking it rather than a well-controlled, well-designed scientific study.'
Due to its vibrant color, methylene blue can also turn human waste products blue or green – a harmless but potentially alarming side effect – and cause teeth staining. 'I had to work with the dentist once because a patient had taken so much meth blue,' Holmes adds. Methylene blue's impact on your health
Beyond cosmetic concerns, doctors warn there are a number of health risks associated with consuming methylene blue as a supplement. The most serious is serotonin syndrome, a rare but potentially life-threatening condition which can occur if it is taken in conjunction with selective serotonin reuptake inhibitors (SSRIs), which are widely used to treat depression and anxiety disorders.
(What's the right way to wean off antidepressants?)
'If you're on an SSRI, it interacts with methylene blue and compounds the drug's effects,' Holmes explains, causing symptoms of anxiety, fast heart rate, sweating, and tremors. In severe cases, the surge of serotonin can lead to seizures, irregular heartbeat, fever, hallucinations, or loss of consciousness.
A 2013 study shows that those with a G6PD deficiency—people missing a key enzyme that protects red blood cells from damage—should avoid methylene blue as it can trigger hemolytic anemia, which is a condition where red blood cells break down rapidly.
Less serious side effects can include headache, dizziness, and nausea, while 'at extremely high doses, paradoxically, we see that methylene blue can be causative of methemoglobinemia, which is the very indication it has been approved to treat,' Cuomo says. 'The concern is that people are taking methylene blue as liquid drops, so it is very easy to overdose.'
(Why supplements may hurt your health more than help.)
If you're concerned about your cognitive health, experts recommend addressing other nutrition and lifestyle factors rather than doing any DIY dosing.
'Unless you really want to turn your toilet bowl blue, there is no compelling reason to take it outside of an indicated medical setting,' says Rothenberg. 'Nootropics that we know absolutely are effective are caffeine, exercise, and appropriate sleep. The latter two specifically are what I would recommend to anyone who wants to boost their cognition.'
