Nowadays there are so many ingredients that purport to help improve skin’s elasticity, brightness, and collagen production, but few are more studied and widely accepted then Vitamin C. For years, research has shown how using vitamin C topically can have huge benefits for skin. If you’re still on the fence about adding this powerful ingredient to your routine, read on.

There are various forms of vitamin C that are often included in skincare, but the most popular is called L-ascorbic acid. “L-ascorbic acid has long been the gold standard for vitamin C in skincare, because it is the raw form of vitamin C. However, it can oxidize quickly with exposure to light, air, or if the formula lacks stability.” Said Erin Larson, Director of Education at HydroPeptide.

If it oxidizes before being applied to the skin, it is not going to provide the benefits normally expected from vitamin C, and you could actually be damaging the skin instead of helping it. Oxidized vitamin C is a “pro-oxidant” meaning it does the opposite of an antioxidant, encouraging free radical damage to the skin.

Another form of Vitamin C is sodium ascorbyl phosphate (SAP.) This form of vitamin C has grown in popularity because of the higher stability and better pH balance levels on the skin. “SAP must be converted by the skin in order to become effective. This means it remains stable much longer,” said Larson.

Many know vitamin C has brightening effects, but in higher dosages, the primary function of vitamin C is collagen stimulation. So whether you’re targeting hyperpigmentation or diminishing signs of aging, vitamin C is the right ingredient to include in your day and night skincare routine.