Should a topical antioxidant serum, such as vitamin C, be applied prior to sunscreen in the morning?

From the Guidelines

Yes, an antioxidant serum like vitamin C should be applied before sunscreen in your morning skincare routine. This is because vitamin C works best when it can penetrate directly into the skin, while sunscreen needs to form a protective barrier on top 1. Apply the vitamin C serum to clean, dry skin and allow it to fully absorb for about 1-2 minutes before applying sunscreen. Vitamin C serums typically contain L-ascorbic acid at concentrations between 10-20% and work by neutralizing free radicals, boosting collagen production, and providing additional photoprotection when paired with sunscreen.

The combination of vitamin C followed by sunscreen offers enhanced protection against UV damage and environmental stressors. For best results, use a pea-sized amount of vitamin C serum for your entire face, and follow with the recommended amount of sunscreen (typically 1/4 teaspoon for the face). It's also important to note that individuals with fair skin, light hair and eye color, or freckles or who sunburn easily are at increased risk for skin cancer and would benefit most from sun protection behaviors, including the use of broad-spectrum sunscreen with a sun-protection factor of 15 or greater, wearing hats or other shade-protective clothing, avoiding the outdoors during midday hours, and avoiding indoor tanning 1.

Some key points to consider when applying vitamin C serum and sunscreen include:

• Using a broad-spectrum sunscreen with a sun-protection factor of 15 or greater
• Wearing hats or other shade-protective clothing
• Avoiding the outdoors during midday hours (10 a.m. to 3 p.m.)
• Avoiding indoor tanning
• Applying vitamin C serum to clean, dry skin and allowing it to fully absorb before applying sunscreen. The USPSTF found convincing evidence linking UV radiation exposure during childhood and youth to a moderately increased risk for skin cancer later in life; for adults, adequate evidence links UV radiation exposure to a small increase in risk for skin cancer 1.

From the FDA Drug Label

Directions: Once In the morning after cleansing and toning, apply 4-5 drops to a dry face, neck, and chest before other anti- aging skincare products. Follow with a moisturizer and sunblock.

• The Ferulic CE serum (containing an antioxidant) should be applied before other anti-aging skincare products and before sunblock.
• It can be inferred that an antioxidant serum like vitamin C should be applied before sunscreen in the morning, as it is similar to the ferulic acid serum in terms of its antioxidant properties and the recommended order of application 2.

From the Research

Application of Antioxidant Serum and Sunscreen

• The application of an antioxidant serum like vitamin C before sunscreen in the morning is a common practice, but its effectiveness depends on various factors.
• Studies have shown that vitamin C can provide additive protection against acute UVB damage when combined with a UVB sunscreen 3.
• A combination of vitamins C and E can provide very good protection from a UVB insult, with the bulk of the protection attributable to vitamin E 3.
• Vitamin C is significantly better than vitamin E at protecting against a UVA-mediated phototoxic insult, while the combination is only slightly more effective than vitamin C alone 3.

Synergistic Effects of Antioxidants and Sunscreens

• The combination of antioxidants like vitamin C, ferulic acid, and phloretin with sunscreens can provide greater than additive protection against phototoxic damage 4, 5.
• Ferulic acid can stabilize and increase the skin availability of topically applied vitamin C and ferulic acid, making it a useful ingredient in antioxidant mixtures 4.
• The addition of antioxidants like ferulic acid to sunscreens can improve their sun protection factor (SPF) and prevent inflammatory reactions 6.

Clinical Applications of Topical Vitamin C

• Topical vitamin C has a wide range of clinical applications, from antiaging and antipigmentary to photoprotective 7.
• Vitamin C is the primary replenisher of vitamin E and works synergistically with vitamin E in the protection against oxidative damage 7.
• However, clinical studies on the efficacy of topical formulations of vitamin C remain limited, and the challenge lies in finding the most stable and permeable formulation to achieve optimal results 7.