Guide to vitamin C serums

Vitamin C, also sometimes called L-ascorbic acid, is a popular ingredient in many skin care products. It is one of the most abundant 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.

Vitamin C and other nutrients are offered in various topical formulations, including creams, ointments, lotions and serums. A serum is usually a very lightweight oil- or water-based product that contains concentrated amounts of active ingredients. Because serums contain concentrated amounts of ingredients, you should test a small area of your skin first for sensitivity. Vitamin C is often added to serums to help with dark spots and skin aging. Vitamin C serums can also help reduce skin damage from the sun and pollution.

Vitamin C is essential for many of our bodily functions. But topical Vitamin C is very different when compared to getting vitamin C from our diet. Research is limited for the topical use of vitamin C on skin, but some studies suggest that a high-quality vitamin C serum may provide some potential benefits for the skin, including:

• Protecting and increasing collagen in skin, which may help minimize fine lines and wrinkles
• Aiding in wound healing 
• Protecting against pollution and UV damage from the sun, especially when used with sunscreen
• Reducing hyperpigmentation, which is dark spots or patches on the skin
• Brightening your complexion

Yes, you can use a vitamin C serum daily in the morning and/or in the evening. Applying it in the morning may offer the best benefits for UV protection, but using it again in the evening may be helpful as well.

Use vitamin C serum as directed by your healthcare provider and the product instructions. Serum products are usually applied after you cleanse but before you apply your moisturizer. This can allow the serum to penetrate your skin first and then the moisturizer can help create a barrier to keep your skin hydrated.

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

If you've never used vitamin C serum, make sure to test it on a small nonsensitive area of skin. If you experience any skin symptoms in the tested area, you should consult with your healthcare provider to determine which products may be appropriate for your skin. You can start with a small amount every other day and increase the amount and frequency over time in order to gradually add it into your skin care routine.

Vitamin C serum may be used by people at any age. Teenagers and young adults may benefit from the potential protective and anti-aging properties down the road. Older adults may find vitamin C serums helpful for reducing dark spots, fine lines and wrinkles.

Different types of vitamin C are used in different serums. On product labels, the active ingredient in vitamin C may be called different names, including L-ascorbic acid and ascorbic acid.

Different concentrations of vitamin C are included in different serums, and most people find a 10% to 20% concentration helpful. However, concentrations higher than 20% may irritate your skin.

Since exposure to heat, light and air can 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 and keep the product sealed tightly.

Vitamin C serum may provide potential benefits for your skin. While additional research is ongoing, current evidence suggests it may minimize dark spots, protect against skin damage from UV rays and environmental pollution. It could also potentially help reduce visible signs of aging. It's important to choose an appropriate skin care routine for your skin type. Ask your healthcare provider for guidance.

Clinically reviewed and updated by Julie McDaniel, MSN, RN, CRNI, January 2024.