If you only add one serum, which should it be? The honest answer is: it depends on what your skin needs today.
Vitamin C — for brightness and protection
Vitamin C is an antioxidant. It brightens dullness, helps fade the look of dark spots, and shields skin from daily environmental stress. Use it in the morning, under sunscreen.
Hyaluronic acid — for hydration
Hyaluronic acid is a humectant. It pulls water into the skin, plumps fine lines and restores a soft, bouncy feel. Apply it to slightly damp skin and seal with moisturiser.
Use both
Vitamin C in the AM for defence, hyaluronic acid AM and PM for hydration. They complement, never compete.

