Is methylene blue safe?
At the low amounts found in a 1% solution, methylene blue is generally well-tolerated by healthy adults. But “safe” always depends on the dose, the person, and what else you take — so here’s an honest, straight account rather than reassurance.
Common, mostly harmless effects
Blue or green urine
The most common and completely harmless effect — your body clearing what it doesn’t use. Expected, not a warning sign.
A blue tongue, briefly
If taken directly rather than in water, it can tint your tongue for a while. Cosmetic and temporary.
More at higher amounts
Larger amounts are more likely to cause mild stomach upset or headache. This is one of several reasons to start low.
Serotonergic medications
Methylene blue can act as a monoamine oxidase inhibitor. Combined with antidepressants (SSRIs, SNRIs, MAOIs) or other medicines that raise serotonin, that can lead to a serious condition called serotonin syndrome. This is the single most important reason not to start methylene blue without medical advice if you take any such medication. If that’s you, talk to your doctor first — don’t self-combine.
Who should not take methylene blue
You take antidepressants or serotonergic medicines
This is the interaction that matters most — see the note below. Do not combine without medical advice.
You have G6PD deficiency
Methylene blue is not suitable for people with this enzyme deficiency. If you’re unsure, ask your doctor before use.
You’re pregnant or breastfeeding
Not recommended without medical guidance. Speak to a healthcare professional first.
You take other prescription medication
Or have kidney issues or an existing health condition — check with a professional before starting anything new.
Safety starts with what’s in the bottle
Much of the real risk with methylene blue comes not from the molecule but from the grade. Industrial or dye-grade material can carry heavy-metal contaminants and impurities. That’s why every batch we make is third-party tested.
Common questions
What drugs should not be taken with methylene blue?+
Methylene blue should not be combined with antidepressants — including SSRIs, SNRIs and MAOIs — or any other medicine that raises serotonin, without medical advice. Combining them can lead to a serious condition called serotonin syndrome. If you take any such medication, speak to your doctor before starting methylene blue.
Who should not take methylene blue?+
Speak to a doctor before taking methylene blue if you take antidepressants or other serotonergic medication, have G6PD deficiency, are pregnant or breastfeeding, or take other prescription medication or have an existing health condition, including kidney issues.
Can methylene blue be taken with antidepressants?+
No, not without medical advice. Methylene blue can act as a monoamine oxidase inhibitor, and combined with antidepressants such as SSRIs, SNRIs or MAOIs it can lead to serotonin syndrome, a serious condition. Anyone taking antidepressant or serotonergic medication should speak to their doctor first rather than combining the two themselves.
What does methylene blue do to your serotonin?+
Methylene blue can act as a monoamine oxidase inhibitor (MAOI). Monoamine oxidase is one of the ways the body breaks down serotonin, so inhibiting it can raise serotonin levels — which is why combining methylene blue with other serotonergic medicines, such as antidepressants, carries a risk of serotonin syndrome, a serious condition caused by excess serotonin.
In short
For most healthy adults, a low-dose 1% solution is well-tolerated — but it isn’t right for everyone, and the medication interaction above is genuinely important. Start low, buy a tested product, and if you take any prescription medication, are pregnant or breastfeeding, or have a health condition, speak to a healthcare professional before use. This page is general information, not medical advice, and the MHRA has not evaluated any statements about this product.
Start with a tested product
UK-made, USP-grade, Eurofins-tested methylene blue 1% in cobalt glass.
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