A new social media trend is making headlines: Methylene blue is being touted as a cognitive booster and antiaging miracle. Influencers such as Ben Greenfield are promoting the use of this chemical to enhance brain performance, strengthen the immune system, and even prevent cancer without providing scientific evidence. Researchers have warned that methylene blue can have dangerous side effects, especially when combined with antidepressants or in individuals with certain preexisting conditions.
What Is Methylene Blue?
Methylene blue is a synthetic dye with versatile applications in medicine, chemistry, and industry. Originally developed in the 19th century by Heinrich Caro, this substance was first used in the textile industry and later in bacteriology and microscopy.
Methylene blue is a redox indicator used in chemistry. It is blue when oxidized and colorless when reduced. This color change makes it useful for biochemical experiments and analytical tests.
Shortly after its initial synthesis, studies began investigating the therapeutic benefits of methylene blue.
Medical Applications
Methylene blue was used as the first synthetic antimalarial agent by Paul Ehrlich 125 years ago. However, the growing resistance of Plasmodium to artemisinin combination therapies (ACT) has rekindled interest in methylene blue. The dye acts as an inhibitor of glutathione reductase in Plasmodium falciparum and affects the hemoglobin metabolism of the parasites. Clinical studies have shown that methylene blue therapy, in combination with ACT, is safe and effective against tropical malaria, particularly notable for its strong effect against gametocytes.
However, this is not all; doctors also use methylene blue as an antidote for nitrite or aniline poisoning. It helps convert methemoglobin back into functional hemoglobin, thereby ensuring an oxygen supply to the body. Methylene blue significantly reduces the time to shock reversal and length of stay in the intensive care unit, as reported by Medscape Medical News.
Associated Risks
Despite its positive properties, the use of methylene blue poses risks. Most manufacturers label the substance with the warning “H302: Harmful if swallowed.”
One of the most severe side effects is serotonin syndrome, which can occur when methylene blue is administered alongside antidepressants, such as selective serotonin reuptake inhibitors or serotonin-norepinephrine reuptake inhibitors. Since methylene blue inhibits monoamine oxidase A, there is a risk for a dangerous increase in serotonin levels, manifesting as symptoms such as confusion, muscle twitching, elevated body temperature, and seizures.
Individuals with glucose-6-phosphate dehydrogenase deficiency must also be cautious of severe side effects of this drug. In these individuals, methylene blue can trigger hemolytic anemia, with symptoms such as pallor, jaundice, dark urine, and weakness. Additionally, it may cause fluctuations in blood pressure.
Alongside these more serious albeit rare risks, there are more common but harmless side effects. These include gastrointestinal issues such as nausea, vomiting, and diarrhea, as well as noticeable blue discoloration of the urine, skin, and mucous membranes. Some patients also reported increased sensitivity to light.
Effect on the Brain
Methylene blue and its derivatives have been investigated as potential treatments for numerous conditions, including stroke, bipolar disorder, Parkinson’s disease, and Alzheimer’s disease. However, this anticipated breakthrough has not yet materialized. Particularly for Alzheimer’s disease, it was long considered a promising candidate, but enthusiasm among researchers has waned. Despite promising early studies, a large investigation involving 890 participants published in The Lancet found that methylene blue did not perform better than placebo.
Can the Hype Be Stopped?
Many individuals seeking to use methylene blue outside of clinical trials or medical recommendations inquire at pharmacies. “We strongly advise against dispensing it in pharmacies,” stated the Federal Association of German Pharmacists’ Associations (ABDA).
“For any inquiry about a chemical, the pharmacist must ask for the intended use.” Methylene blue is neither an approved medication nor a dietary supplement.
According to the ABDA, there is no obligation to dispense chemicals. Therefore, pharmacists are not required to sell these chemicals.
To summarize, methylene blue is a fascinating molecule with a long history and potentially diverse applications, from malaria therapy to treating poisonings. However, while there are possible medical uses, its efficacy as a dietary supplement or cognitive enhancer remains questionable, if not dangerous to use.
This story was translated from Medscape’s German edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.