Circadia is an American cosmeceutical brand founded and developed by Dr. Peter T. Pugliese. The specialist has over 30 years of experience in scientific skin research. Dr. Pugliese is the author of the textbooks Advanced Professional Skin Care and The Physiology of the Skin, and an innovator in cosmetic chemistry who focuses on the study of peptides, β-glucan, vitamin E, and other active ingredients.

Circadia places great emphasis on the human circadian rhythm: during the day it focuses on protecting the skin from UV radiation, stress, and oxidative processes, while at night it emphasizes recovery, nourishment, and repair. Circadia formulas include peptides, unconventional antioxidants, valuable plant extracts, and complex blends. The brand also uses specialized delivery technologies and patented ingredients whose efficacy is confirmed by clinical studies.