US sunscreen is less effective than those in other countries.

The strongest sunscreen you can possible get at the moment is La Roche Posay fluids with UVMune400. Not a single sunscreen offers better broad spectrum and especially UVA protection because only L’Oréal brands can use this patented filter (INCI: Methoxypropylamino Cyclohexenylidene Ethoxyethylcyanoacetate).