AlphaCeuticals Serum is the "working" product in this great face care regimen. The glycolic acid loosens the deadskin cells that tend to adhere and not shed as we get older giving our skin that dull, wrinkled look. Baby softskin emerges with consistent use of a serum. The stronger formulas, like 15 and 20, can help if your skin is darkenedor toughened by weather damage. Serum 5 and 10 are great for fair complexions and skin that has thinned with aging.AlphaCeutical Serum contains Glycolic Acid derived from natural sugar cane, to help lower the pH value. This Serum comes in four different strengths. Skin will begin to feel softer, fine lines and skin discolorations will begin to minimize. Skin will appear to be younger and healthier. 1.7 fl. oz.