[en] A large magnetic moment or transition moment of the neutrino have been suggested as explanations for the solar neutrino puzzle. These scenarios have the attractive feature of incorporating an anticorrelation of the solar neutrino flux with sun spot activity. Recently it has been claimed that the 1987 supernova results put a severe bound on the neutrino magnetic moment, allowing only values that are too small to account for the solar neutrino flux depletion. Here we show that this bound does not apply to the transition magnetic moment of Majorana neutrinos. Other laboratory, astrophysical and cosmological bounds are also discussed. (orig.)