What are the active ingredients in Unisom products? SleepGels: The active sleep-aid ingredient is diphenhydramine HCl (50 mg/dose). SleepTabs: SleepTabs contain doxylamine succinate (25 mg/dose). SleepMinis: The active sleep-aid ingredient is Diphenhydramine HCl (50 mg/dose). Unisom Liquid: The active sleep-aid ingredient is diphenhydramine HCl (50 mg/dose or 30mL/dose). SleepMelts: The active sleep-aid ingredient is diphenhydramine HCl (50 mg/dose). PM Pain: The active sleep-aid ingredient is diphenhydramine HCl (50 mg/dose).