  An analytical result for Euler-Heisenberg effective action, valid for
electron spin $g-$factor $|g|<2$, was extended to the domain $|g|>2$ via
discovered periodicity of the effective action. This allows for a simplified
computation of vacuum instability modified by the electrons measured
$g=2.002319$. We find a strong suppression of vacuum decay into electron
positron pairs when magnetic fields are dominant. The result is reminiscent of
mass catalysis by magnetic fields.
