Sensai To use Sensai Cellular Performance Serum , start with a clean and dry face. Take a small amount of serum onto your fingertips and gently massage it into your skin, starting at the center of your face and working outward. Allow the serum to fully absorb into your skin before applying any other products. Once the Sensai Cellular Performance Serum has absorbed, follow with your regular moisturizer. Face Serums