Do deshedding shampoos actually reduce shedding?

Opinion is genuinely split. Some doggrooming community members say certain deshedding shampoos 'melt the hair off in globs' on double-coated breeds, while others in the same threads say they make 'no difference at all.' The consensus is that deshedding shampoos loosen dead undercoat to make brushing and drying easier rather than stopping natural shedding, and results vary a lot by coat type.