▶ METHYLENE BLUE · SUBTOPIC · SAFETY PROFILE
METHYLENE BLUE Safety Profile
For Laboratory Research Use Only. This page summarises observed adverse events and regulatory status reported in the peer- reviewed literature. It is not medical advice and does not recommend any human use of METHYLENE BLUE.
OBSERVED ADVERSE EVENTS IN LITERATURE
The following adverse events have been observed in trials or animal studies of METHYLENE BLUE. Severity, frequency, and attribution depend on the source publication.
- Blue urine and stool discoloration (expected)
- Blue skin/sclera tint at higher doses
- Headache
- Dizziness
- Serotonin syndrome risk (MAO inhibition)
- Hemolysis in G6PD deficiency
DRUG INTERACTIONS
The following interactions are reported in or theorised from the published mechanism for METHYLENE BLUE.
- SSRIs / SNRIs / serotonergic agents (serotonin syndrome risk · methylene blue is a reversible MAO-A inhibitor)
- Tramadol (serotonin syndrome risk)
CONTRAINDICATIONS REPORTED IN LITERATURE
Contraindications recorded for METHYLENE BLUE in the published record:
- G6PD deficiency
- Recent serotonergic drug use
- Severe renal impairment
- Pregnancy/lactation (caution)
FDA REGULATORY STATUS
Approved as Provayblue (IV methylene blue, 2016) for acquired methemoglobinemia in adults and pediatric patients. Off-label oral use in research and clinical contexts.
WADA REGULATORY STATUS
Not currently listed on the WADA Prohibited List (2026).
SAFETY Q+A FROM LITERATURE
▶ What is methylene blue?
Methylene blue is a phenothiazine dye with documented FDA-approved use for methemoglobinemia (Provayblue, 2016, IV 1-2 mg/kg). It also acts as an alternative electron carrier in the mitochondrial electron-transport chain, the basis for research applications in cognitive aging, neuroprotection, and mitochondrial dysfunction.
▶ Is methylene blue FDA-approved?
Yes for one specific use: Provayblue (IV methylene blue) is FDA-approved for acquired methemoglobinemia. Off-label oral use for cognitive research and mitochondrial-dysfunction research is not FDA-approved.
▶ What are the side effects?
Blue urine and stool discoloration are expected at any dose. Higher doses produce blue skin/sclera tinting. Methylene blue is a reversible MAO-A inhibitor and produces serotonin syndrome risk when combined with SSRIs, SNRIs, or other serotonergic agents. G6PD deficiency contraindicates use due to hemolysis risk.
▶ Why is the serotonin syndrome warning important?
Methylene blue inhibits monoamine oxidase A (MAO-A), the enzyme that clears serotonin from synaptic clefts. Combined use with SSRIs, SNRIs, tramadol, or other serotonergic agents produces additive serotonin accumulation and risk of serotonin syndrome (hyperthermia, agitation, myoclonus, autonomic instability). This is a major contraindication.
▶ Is methylene blue WADA-prohibited?
Methylene blue is not currently listed on the WADA Prohibited List as of 2026.
CITED LITERATURE
The safety statements above are drawn from the following peer-reviewed sources. Refer to the originals for adverse- event tables, attribution, and full context.
- Wen Y, Li W, Poteet EC, et al.. Alternative mitochondrial electron transfer as a novel strategy for neuroprotection. J Biol Chem 2011. PMID 21357427. link
- Oz M, Lorke DE, Petroianu GA. Methylene blue and Alzheimer's disease. Biochem Pharmacol 2009. link
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▶ LAST UPDATED · 2026-05-25