It decreases transepidermal water loss (TEWL), allowing your skin to better retain moisture.

Vitamin C application has been shown to impede melanin production, the pigment responsible for skin color. 

Vitamin C serums can help smooth out fine lines by plumping and hydrating the under-eye area.

Although vitamin C is more effective at reducing overall redness, some people say it can help alleviate discoloration associated with under-eye circles.

According to a small 2009 studyTrusted Source, vitamin C in the form of 10 percent sodium ascorbate was found to improve dark circles of the lower eyelid after 6 months of use by thickening the eyelid dermis and concealing dark coloration due to congested blood.

Some other ways to help get rid of under-eye bags include using a cold compress and adding retinol to your skin care routine.

Since it impedes melanin production, vitamin C can actually fade hyperpigmentation.

Hyperpigmentation — including sunspots, age spots, and melasma — occurs when melanin is overproduced in certain areas of the skin. It can also happen in areas where acne has healed.

Vitamin C inhibits melanin synthesisTrusted Source by downregulating the activity of an enzyme known as tyrosinase. It’s widely used in dermatology for depigmentation of hyperpigmented spots on the skin.

It’s also been used for treatment of gingival melanin hyperpigmentation (gum hyperpigmentation), though studies are limited.

Vitamin C has also been shown to act as an anti-inflammatory agent through its antioxidant capacity, according to a 2015 reviewTrusted Source. This means it soothes your skin and reduces puffiness, letting your face shine through.

Vitamin C’s anti-inflammatory action may helpTrusted Source:

• neutralize free radicals that cause oxidative damage
• optimize the immune system to discourage inflammatory immune response

The anti-inflammatory properties of vitamin C can also help reduce redness, which in turn can create a more even complexion. The combined reduction of dark spots, redness, and irritation make for a clear, smooth skin tone.

Collagen is a naturally occurring protein that depletes over time. Lower levels of collagen can lead to fine lines and wrinkles.

Vitamin C is well known for boosting collagen productionTrusted Source through the process of collagen synthesis. In fact, collagen synthesis can’t happen without vitamin C.

This is because vitamin C is the essential cofactor for the two enzymes required for collagen synthesis:

• prolyl hydroxylase, which stabilizes the collagen molecule
• lysyl hydroxylase, which provides structural strength

Collagen production is tied to skin elasticity and firmness. When your collagen levels begin to drop, your skin may begin to sag.

Applying a vitamin C serum may boost collagen production, resulting in an overall tightening effect, reports a 2017 reviewTrusted Source. 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.