Abstract A normalization condition for the muon decay current in V-A theory with radiative corrections included is obtained by the requirement that the generalized charges corresponding to the constituents of the current should fulfil an appropriate charge algebra. It is shown that the radiative corrections in second order are uniquely fixed by this requirement. The calculation is performed without the use of a cut-off. If the corresponding current algebra is postulated, the currents which, according to Adler, describe scattering of neutrinos on charged leptons, are completely determined. It is pointed out that Adler's Lagrangian for this process must be reduced with a factor 1 2 in order to make leptonic spin symmetric the whole interaction Lagrangian for leptonic processes.