Methylene blue has been around for quite a while, but it is resurfacing due to social media popularity. A few claims are circulating on the internet: that methylene blue can increase energy, improve blood flow to the brain, and fight depression. Today, we’re looking at a few myths and facts about methylene blue.
What is methylene blue?
Methylene blue is a dye that was invented in 1876. Originally, it was used for staining clothing. Later on, it was used to treat malaria, becoming one of the world’s first synthetic medicines. It is an effective way to stain bodily tissues during some clinical procedures to help identify abnormalities in the tissues, such as pre-cancerous growths.
Uses
Today, methylene blue is most often used to treat methemoglobinemia. This is a rare condition where red blood cells cannot carry oxygen the right way. It helps the blood carry oxygen better. Once oxygen levels return to normal, the effect stops. This means it cannot give a person extra or “superhuman” oxygen-carrying ability, even if more is used.
Methylene blue may also be used in certain emergencies, such as severe low blood pressure (vasodilatory shock) and cyanide poisoning. It was once used to treat malaria, but today there are better treatments that work more effectively and have fewer risks.
There are also some claims about other uses for methylene blue, but they are not proven. One is that it slows aging by helping cells make energy more efficiently. Another is that it improves focus by increasing blood flow to the brain. Neither of these claims is backed up by medical evidence. In fact, one study found that it decreased blood flow to the brain by 8%.
How does it work?
Methylene blue works as a redox agent, meaning it can accept and donate electrons. In some research, that redox activity appears to help mitochondria (often called the powerhouse of the cell) use energy more efficiently by supporting electron transport. However, those findings do not mean that it is proven to boost energy or reverse the aging process in healthy people.
Additionally, healthcare providers use methylene blue to help identify tissues because it can stain certain areas more clearly during a procedure. This makes it easier to spot abnormalities, including precancerous growths, so providers can evaluate or remove them more accurately.
There is some discussion about methylene blue’s ability to treat depression, as it can inhibit serotonin from being broken down in the brain. However, it has not been shown to be an effective treatment. Additionally, it is dangerous to take methylene blue with antidepressants called Selective Serotonin Reuptake Inhibitors (SSRIs) (more on this below). Always talk to a healthcare provider first before beginning any new supplements.
Is methylene blue safe?
Methylene blue may be safe if it is used under the guidance of a medical professional. There are a few instances where it could be quite harmful. This is the case for people with a condition called G6PD deficiency. Combined with G6PD deficiency, methylene blue may trigger hemolysis, which is the rapid breakdown of red blood cells. This can become a medical emergency if the red blood cells break down too quickly.
Additionally, it’s important to avoid methylene blue if you take an SSRI unless a clinician specifically says it is safe. Methylene blue can inhibit monoamine oxidase, an enzyme involved in breaking down serotonin. SSRIs increase serotonin by blocking its reuptake. Together, these effects can lead to dangerously high serotonin levels and serotonin syndrome. You can read more about serotonin syndrome in our blog post here.
Methylene Blue Side Effects
Some of side effects may include:
- Nausea
- Headache
- Dizziness
- Blue or green urine or stool
- Changes in skin or eye color
More serious risks can happen in certain people, especially if methylene blue is taken incorrectly or taken with medications that interact with it.
Does methylene blue cure cancer cells?
Methylene blue can help doctors find pre-cancerous growths. However, it does not “cure” cancer. The confusion may come from its role in photodynamic therapies.
In photodynamic therapy, a special drug (such as methylene blue) is given first. Then, a light—often a laser—is used to activate the drug in a targeted area. This process is different from treatments like chemotherapy, which affect how cancer cells grow and divide.
Photodynamic therapy needs to be completed in a clinical setting to be effective. In other words, taking methylene blue as a dietary supplement is not going to remove cancer cells from the body.
Have questions? Call the Missouri Poison Center
Methylene blue has a time and place in clinical settings, and may be harmful if used incorrectly. Be sure to consult with a trusted healthcare provider before beginning a supplement, and call the Missouri Poison Center with any poison-related questions. We are open 24 hours a day, 7 days a week. Every call is fast, free, and confidential.
If you or someone you know has taken methylene blue and has symptoms like shortness of breath, a blue discoloration of the skin, or loss of consciousness, call 911 immediately.
Frequently Asked Questions
Methylene blue has very specific anti-parasitic properties. It can kill the parasite that causes malaria. It is also being researched as treatment for another parasite called Strongyloides. Beyond this, there is no evidence that it can treat other parasitic infections. You can read more about parasite cleanses in our blog here.
No. Medical methylene blue is a prescription medication or clinical reagent, while some products sold online are marketed as supplements or “brain boosters.” Those products may not be appropriate for medical use, and their quality and purity can vary.
Call the Missouri Poison Center right away if someone has swallowed methylene blue unexpectedly, taken too much, or mixed it with medications that may interact. A specially trained nurse or pharmacist can help you determine whether symptoms need urgent medical care.
Methylene blue can irritate the eye and may cause temporary pain, redness, tearing, or blurred vision. If it gets in your eye, remove contact lenses and rinse it right away with lukewarm water for at least 10 minutes. If symptoms continue, or if there is severe pain or vision changes, seek medical care immediately or call the Missouri Poison Center.
Referencing content from this page? Please attribute the Missouri Poison Center with either of these links:
https://missouripoisoncenter.org/ or https://missouripoisoncenter.org/methylene-blue/
Suggested APA citation:
Hazelbaker, H.J. (2026, July 7). What is methylene blue and is it safe? Missouri Poison Center. https://missouripoisoncenter.org/methylene-blue/