Ascorbic acid is vitamin C, an antioxidant that's occasionally used as a dietary supplement or to prevent and treat scurvy (a disease caused by a lack of vitamin C in the body). 

People also commonly take vitamin C to lessen the severity of symptoms associated with the common cold. Vitamin C is essential for maintaining healthy bones, teeth, connective tissue, muscles, skin, and capillaries. It also helps your body absorb iron. Numerous foods are naturally rich in vitamin C, including citrus fruits, leafy vegetables, and tomatoes.

Vitamin C has an excellent safety profile. Most people can use topical vitamin C for an extended period of time without experiencing any adverse reactions. It may cause minor skin irritation in concentrations above 20%. Because of this, its concentration usually ranges between 10% and 20% in skin care products.

Vitamin C can also help fade pigmentation and smooth the skin's surface to reduce dullness. This gives the skin a youthful glow. Its use has been shown to impede melanin production. Melanin is the pigment responsible for skin color. By inhibiting melanin production, vitamin C can help fade dark spots and hyper pigmentation. It may also help brighten your skin's appearance.

Collagen production is tied to skin elasticity and firmness. When your collagen levels begin to drop, your skin may also begin to sag. Applying a vitamin C serum may boost collagen production, resulting in an overall tightening effect. This is true for sagging due to natural aging, oxidative stress damage, or extreme weight loss. This means it can help reduce the appearance of sagging skin, making your skin look firmer and more toned.

What's more, it is involved in all phases of wound healing. In the inflammatory phase it is required for neutrophil apoptosis and clearance. During the proliferative phase, vitamin C contributes towards synthesis, maturation, secretion and degradation of collagen.