Vitamin C effervescent tablets are usually recommended to be taken 2-3 hours before going to bed at night, orally for the following reasons: 1, Vitamin C effervescent tablets are acidic drinks, which are usually not recommended to drink on an empty stomach. 2, after taking vitamin C effervescent tablets try to avoid going out to receive ultraviolet stimulation, because vitamin C effervescent tablets will reflect on the direct sunlight, so that the face produces spots, it is recommended to take vitamin C effervescent tablets at night before going to bed, the most beneficial to the body.