Research supports that it is fine to do so but it’s not required. Although refrigerating many types of skin care products can hinder their stability and performance, research has shown vitamin C (ascorbic acid) in water-based formulas remains stable and effective in cold temperatures as well as room temperature, 68–72F (20–22C) upwards of 77F/25C. If you live in a hot, humid environment without air conditioning, you may want to keep your C15 Super Booster stored in the refrigerator or other cooler spaces in your home.