As we use hyaluronic acid of different molecular weights in Hydra-Fill Concentrate and Mask, they affect the skin differently. Hydra-Fill Concentrate has a more pronounced stimulating effect, restoring the synthesis of the agents and substances which enhance the skin’s moisturising. Hydra-Fill Mask, on the other hand, has a more calming effect, brightens the skin and instantly smooths it out with the glowing effect lasting for several days. After using the mask, the skin’s condition allows for a stronger effect of the concentrate’s active molecules. We recommend using concentrate and mask in combination. This doesn’t mean that one won’t work without the other, but together they certainly have maximum effect on the skin.