Formulated for Skin Microbiome Type 4, Cepheus: Active Phage Serum contains a targeted phage cocktail, containing over 1 billion phages per mL, that combats your specific strains of issue-causing S. aureus bacteria. Powered by Parallel’s unique, high-titer phage technology, Cepheus naturally knocks back your bad bacteria and enables good bacteria to grow, supporting balance, clarity, and radiance. Dermatologist-approved for healthy, youthful, more resilient skin.