Verification of radical pair mechanism predictions for weak magnetic field effects on superoxide in planarians

Weak magnetic field effects in biology are increasingly attributed to quantum phenomena involving coherent electronic spin dynamics, yet experimental support remains limited outside of avian magnetoreception. In this work, we verified the predictions of a minimal radical pair model for magnetic field modulation of superoxide levels during planarian regeneration. The model predicted increased superoxide concentrations at both near-zero and higher magnetic fields—outcomes that conflicted with prior biological expectations. Surprisingly, our experiments confirmed these predictions. While questions remain about the specifics of radical pair chemistry, this work substantially strengthens the case for quantum biological interpretation of the weak magnetic field dependence of superoxide generation.