Selected findings from three October 2026 methylene blue publications
Why it's in the news
In October 2026, PolitiFact and the American Cancer Society published articles discussing methylene blue and products marketed online. PolitiFact published an explainer on October 30, 2026, examining online wellness claims about methylene blue and the evidence cited for them. The American Cancer Society published "What to Know About Methylene Blue" on October 15, 2026. A research article in the journal Toxics, published October 24, 2026, included a survey of methylene blue products offered to consumers in the European Union.
The indication described in the January 2024 ProvayBlue label
Section 1 of the January 2024 FDA label lists acquired methemoglobinemia in pediatric and adult patients as the indication for ProvayBlue, an intravenous prescription product (see What is methylene blue?).
The American Cancer Society states that the FDA has approved methylene blue for only one use, methemoglobinemia, and that health claims promoted online have not been proven. This summary does not independently determine the regulatory status of any individual product.
Topics both publications cover
PolitiFact and the American Cancer Society discuss risks associated with methylene blue, including serotonin syndrome and G6PD deficiency, as well as differences between prescription products and products marketed online (see the FDA warning and G6PD deficiency and methylene blue). The cited January 2024 label includes a boxed warning on serotonin syndrome and lists G6PD deficiency as a contraindication. This page identifies those topics without providing instructions for product use.
PolitiFact notes that methylene blue is also used to disinfect aquarium tanks and dye fabric, and that products purchased online may vary in purity and contain unknown ingredients.
What the Toxics article reports
According to the accessible abstract, the authors surveyed 63 products offered to consumers in eight EU member states. The abstract reports that five products stated an intake amount, and describes the products as mostly declared laboratory chemicals, reagents, or dyes rather than food supplements. The abstract discusses the absence of an established health-based guidance value for oral intake and reports a provisional value proposed by the authors. This page does not reproduce, endorse, or interpret that proposed value. The product observations concern how products were offered and labeled and do not establish their actual composition. The abstract also summarizes toxicological modeling and exposure assessment. This page summarizes the accessible abstract, not the full paper. The cited survey does not evaluate recordkeeping or MB Dose Log.
Clinician comments
The cited publications also include clinician commentary. This page does not summarize or reproduce clinical recommendations.
This page provides a descriptive summary of the cited sources, not medical advice, dosing guidance, or instructions for product use or medical action. References to a prescription product concern that product and the cited label version. Source citations do not imply endorsement of MB Dose Log.