Guide to vitamin C serums

By Dr. Anna H. Chacon, MD, Fellow of the American Academy of Dermatology Nov 17, 2021 • 5 min.

Vitamin C is a popular ingredient in skin care products.

It is one of the most powerful antioxidants in the skin and an important building block of collagen, a protein that helps keep skin and bone tissue strong. Evidence suggests that vitamin C can help reduce sun damage and signs of aging when applied topically. Here, we'll look at what vitamin C serums are, how they help your skin and what you should look for.

What is vitamin C serum?

Vitamin C and other nutrients are delivered to the skin through various topical formulations, including creams, ointments, lotions and serums. A serum is a very lightweight product that contains concentrated amounts of active ingredients. Because they're formulated with very small molecules, serums penetrate the skin quickly and deeply, delivering the active ingredient to the skin cells. Vitamin C serums contain concentrated amounts of the vitamin to deeply nourish your skin.

What does vitamin C serum do for the skin?

A high-quality vitamin C serum may provide several potential benefits for the skin, including:

  • Minimizes fine lines and wrinkles
  • Aids in wound healing by stabilizing collagen
  • Protects against pollution and UV damage from the sun
  • Reduces hyperpigmentation—dark spots or patches on the skin
  • Brightens your complexion

Can you use vitamin C serum every day?

Yes, you can use a vitamin C serum in the morning or in the evening—or both. Applying it in the morning may offer the best benefits for UV protection, but since UV light reduces vitamin C levels in the skin, using it again in the evening replenishes the stores.

Use vitamin C serum after you cleanse but before you apply your moisturizer. The serum will penetrate your skin, and a thicker moisturizer will create a barrier on the skin to help keep hydration in.

What are the possible side effects of vitamin C serum?

Vitamin C serum may cause burning or tingling if you have very sensitive skin or an allergy or intolerance to vitamin C or other ingredients in the product.

If you've never used vitamin C serum, test it out on a nonsensitive area of skin, such as on your leg. If your skin doesn't react, gradually introduce the product into your skin care routine. Start with a small amount every other day, and increase the amount and frequency over time.

When should you start using a vitamin C serum?

You can use a vitamin C serum at any age. Tweens may choose to use it for its potential to reduce acne breakouts and scars, while teenagers and young adults could benefit from its protective and anti-aging properties down the road. Older adults may find vitamin C serums helpful for reducing dark spots, fine lines and wrinkles.

What should you look for in a vitamin C serum?

Different types of vitamin C are used in different serums. On product labels, vitamin C goes by several different names, and one of the optimal choices is L-ascorbic acid, which is the most effective.

Different vitamin C serums also have different concentrations of vitamin C, ranging from under 5% to 30%, but the effects tend to plateau after 20%, and concentrations higher than that may irritate your skin.

Other ingredients to look for in a quality vitamin C serum include:

  • Vitamin E (aka tocopherol), which stabilizes vitamin C for maximum protection
  • Glutathione, an antioxidant that boosts the effects of vitamin C
  • Ferulic acid, which lowers the pH of vitamin C to improve penetration

Since exposure to heat, light and air will degrade a serum containing L-ascorbic acid, choose a product that comes in a dark glass bottle or a tube. Store the serum in a cool, dark place.

Vitamin C serum may have substantial benefits for skin. While additional research is ongoing, current evidence suggests it may minimize skin damage from UV rays and environmental pollution, and could potentially help reduce visible signs of aging and dark spots. It's important to choose the best vitamin C serum for your skin type and test it out on a small patch of skin on your leg or arm before applying it to your face. If you're unsure whether you should use a vitamin C serum, check with your dermatologist.

Published November 2021.

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12 min.
By Dr. Anna H. Chacon, MD, Fellow of the American Academy of Dermatology
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