Methylene blue makes mitochondria produce more hydrogen peroxide, but if you block a specific part of the energy chain (Complex III), that extra production stops—meaning methylene blue needs that part to work.
Scientific Claim
Methylene blue (0.5–2 μM) increases hydrogen peroxide (H2O2) production in mouse brain mitochondria oxidizing pyruvate + malate, but this increase is suppressed by antimycin (Complex III inhibitor), suggesting that reduced methylene blue is oxidized at the Qo site of Complex III rather than directly by cytochrome c or oxygen.
Original Statement
“Antimycin decreased the rate of MB-induced H2O2 production by 25.4% in the presence of 0.5 μM MB, by 87.6% in the presence of 1μM MB, and by 95.9% in the presence of 2 μM MB... these data strongly suggest that reduced MB is oxidized at Qo site of complex III, not by the cytochrome c.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
definitive
Can make definitive causal claims
Assessment Explanation
The study used precise fluorometric measurements of H2O2 under controlled inhibitor conditions. The dose-dependent suppression by antimycin provides direct mechanistic evidence for the proposed site of oxidation.
Evidence from Studies
Supporting (1)
Methylene blue does not bypass Complex III antimycin block in mouse brain mitochondria
The study shows that methylene blue makes brain mitochondria produce more hydrogen peroxide, but only if a key part of the energy system (Complex III) is working; if you block that part, the hydrogen peroxide stops, meaning methylene blue needs that part to work, not some other route.