This acid is a great option for oily and acne prone skin. While AHAs are exfoliants, vitamin C is a natural antioxidant that fights free radicals and keeps you healthy. When used for skincare, vitamin C fights off free radicals. Free radicals break down the collagen and elastin found in skin, which are essential to keeping skin firm and healthy. While vitamin C may be efficacious, it is also very unstable and loses its potency very quickly, which can make a cream virtually worthless.
Packaging is important, too, as vitamin C can oxidise very quickly when exposed to air and light.
Look for a product in an airtight brown glass bottle or metal tube, which will screen out light and prevent air from seeping in and breaking down the vitamin. Be sure to recap it tightly and store it a cool, dark place to prolong its shelf life. Both AHAs and vitamin C will help reduce signs of ageing, but you will see optimum results faster if you use them in conjunction with each other. If you have oily or combination skin, an AHA or salicylic acid cleanser or toner works best in the morning, followed by a vitamin C serum at night. Skin Enemies Smoking.