It is a skincare product packed with the powerful antioxidant vitamin C.
It stimulates collagen production, fights fine lines, and brightens the complexion.
Twice a day.
Experts suggest four ways to determine its effectiveness.
Should be dark since the serum loses effectiveness when exposed to light.
Should be between 2.5 and 3.5.
Should be 5–20%, based on skin type.
Should not be mixed with other ingredients that it may destabilize.