The Devanathan and Stachurski diffusion membrane method was used to study the evolution of hydrogen and its permeation into a steel sheet during cathodic charging from a chloride electrolyte or during zinc electroplating. The influence of four different organic compounds, which are the components of various formulations derived to improve zinc electrocoatings, were also tested. At a high-charging current density, the permeation transients obtained in a chloride electrolyte without zinc ions exhibit a maximum attributed to hydrogen trapping in the subsurface layer on the entry side. The concentration of adsorbed hydrogen on the steel surface depends not only on the cathodic current density and the composition of the solution, but also on the influence of the organic additives on the recombination of hydrogen atoms. During zinc electrodeposition, the coating covers the substrate in a few seconds and acts as a barrier for hydrogen absorption. The permeation rate depends on the cathodic current density but also on the concentration of ZnCl2 in correlation with the porosity of the coating. It is shown that steel substrate hydrogenation (beneath the zinc coating) is strongly reduced in the presence of a combined additive, composed of four compounds in appropriate amounts as well as in the presence of PEG(6000) in the plating bath. This effect, which is correlated to the modification of the hydrogen evolution process, can be used to hinder the severe drawbacks caused by hydrogen penetration into the steel substrate.