A topical lotion that contains the enzyme T4-bacteriophage endonuclease V encapsulated within liposomes. With topical liposomal delivery, the DNA repair enzyme T4-bacteriophage endonuclease V is transported into skin cells, where the enzyme enters cell nuclei and binds to and incises pyrimidine dimers, thereby catalyzing the first reaction step of the cellular excision repair pathway for removing DNA replication-inhibiting pyrimidine dimers produced within duplex DNA through exposure to ultraviolet (UV) irradiation. In vitro and in vivo studies indicate that T4N5 liposomes increases repair of DNA damage caused by UV irradiation.