  We study the magnetic moment of leptons in extremely hot universe and
superdense media of stars at high temperatures. Anomalous magnetic moment of
charged leptons is inversely proportional to its mass, whereas, the induced
dipole moment of neutral leptons is directly proportional to their mass.
Neutral massive point particles exert nonzero magnetic moment as a higher order
effect, which is smaller than the anomalous magnetic moment of a charged
particle of their same flavor partner. All leptons acquire some extra mass due
to their interaction with the medium and affect the magnetic moment
accordingly. We compare the contribution to the magnetic moment of various
leptons due to their temperature and chemical potential dependent masses. It is
shown that the magnetic moment contributions are non-ignorable for lighter
leptons and heavy neutrinos. These calculations are very important to study
particle propagation in the early universe and in superdense stellar media.
