Restoring S.I. units to a Lagrangian in natural units

If we have a natural unit Lagrangian, where some fundamental quantities have been excluded to ease calculations...and aim to restore it's S.I units back, do we just have to plug back the fundamental quantities that were initially excluded Into the Lagrangian...or we use some specific scaling factors corresponding to that field that has the same S.I units of Lagrangian density, and scale the unitless Lagrangian with it.

"fundamental quantities" are not excluded in using natural units.
Only quantities relating two different dimensions are excluded.