It used to be that you got blue tongue from knocking back an obnoxious alcopop or one too many Tango Ice Blasts at the cinema, but many celebs are swearing by something called methylene blue which has the exact same effect.
Have you ever seen the film Limitless? Starring Bradley Cooper and released in 2011, it tells the story of a fictional man called Edward Morra, a writer who is introduced to a so-called 'Limitless pill' that promises to improve his brain function.
Spoiler alert: it doesn't end well for him.
Back in the real world, and in 2025, influencers and celebrities alike are raving about a similar substance called methylene blue.
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What is methylene blue?
As the name suggests: this stuff is bright, bright blue, and not only does it turn your tongue blue but your urine too.
Methylene blue was originally used as a fabric dye, but in the late nineteenth-century it was found to have an additional use for treating malaria.
The vibrant substance has also been used as a treatment for a blood disorder called methemoglobinemia.
This is a condition where the red blood cells don't carry enough oxygen around the body.
In recent months, high-profile celebrities and influencers have raved about the stuff, saying it boosts brain power and mood.
Biohacker Bryan Johnson at one time swore by it for anti-aging properties, as he documents his attempts to reverse ageing.
He has since stopped using it.
What does methylene blue do?
Some influencers have been dubbing methylene blue a 'nootropic'; a catch-all term for a substance which can boost brain power, and improve focus and creativity.
Fans say it makes them sharper, improves mood and boosts brain function - but very limited clinical research and studies have been carried out on these specific claims.
In reality, methylene blue works by crossing the protective tissue barrier which surrounds your brain - although it is used in hospital environments.
What are the risks of methylene blue?
Dr Adjoa Boateng Evans is an ICU physician and anaesthesiologist at Duke (previously Stanford) who cares for critically ill patients, and has extensive experience of administering and managing methylene blue for critically ill patients.
She explained: "I use this to take care of patients who are critically ill and sometimes on the verge of death.
"In the operating room, surgeons ask us to administer it to highlight important structures. In the intensive care unit, after patients have a transplant or come off a cardiopulmonary bypass, they are at risk of something called vasoplegic syndrome, which is dangerously low blood pressure, so we use methylene blue in these instances.
She told Tyla: "Over the last few years, I’ve seen a clear increase in individuals asking about methylene blue due to celebrity and social-media promotion."
But she wants there is a risk of 'very dangerous' side effects when the substance is used alongside SSRI (selective serotonin reuptake inhibitors) antidepressant medication.
Dr Adjoa explains: "The combination of methylene blue and SSRI medications can cause serotonin syndrome. It can present with agitation, high fever, nausea, vomiting, and can even lead to coma and death."
Is there a safe way to take methylene blue?
Dr Adjoa strongly advises against it: "As a physician, currently there is no validated 'wellness' or at-home dosing protocol," however if someone insists on taking it, she advises; "Always involve a physician! First, they should get tested for G6PD deficiency as this combination can cause blood cells to break, which causes anaemia and damage to the kidneys."
"Start at the lowest dose, remove any non-pharmaceutical products. Stop immediately if side effects or symptoms of toxicity occur. But none of these will completely eliminate the risk, they will simply reduce it."
Dr Adjoa finishes by saying that methylene blue is effective only 'primarily in medical emergencies like shock and methemoglobinemia. Wellness benefits remain theoretical, and strong human data is lacking."
What should you take instead?
Anee Qua is a registered nutritionist, and she told Tyla: "Methylene blue is increasingly marketed as a ‘Limitless’ brain enhancer, but the reality is that much more research is needed, and it should only be used under expert supervision.
"For anyone looking to support cognitive function and healthy ageing, there are far safer, evidence-based options such as omega-3s, CoQ10, and NAD-supporting nutrients, alongside sleep, nutrition, stress management and exercise."
Topics: Health, Mental Health
Jen Thomas