The prime benefit of its use in cosmetic dermatology is to extend the protective ability of daily-use sunscreens against photoaging beyond their existing capabilities, which are largely inadequate to prevent premature aging.

When applied underneath broadest protection sunscreens, fresh Skinceuticals C E Ferulic Serum (manufactured and used within four months) provides approximately eight times the skin's naturally-endowed level of protection against ultraviolet.

Applied underneath sunscreen, Skinceuticals C E Ferulic prevents the accumulation of approximately 55% more permanent UVA/UVB-induced permanent skin degradation than sunscreen alone.

For the best prognosis possible, daily sunscreen use alone is inadequate to prevent photoaging symptoms, namely:

• Fine lines and wrinkles;
• Irregular texture;
• Decreased firmness (collagen loss) — for further information, see the La Roche-Posay Aging Skin Video;
• Decreased dermal volume and hydration (glycosaminoglycans) — for further information, see the La Roche-Posay Mature Skin Video;
• Broken capillaries;
• Changes in colouring (such as yellowing and hyperpigmentation); and
• Skin cancer.

Skinceuticals C E Ferulic's preventive effect is brought by its supplementation of the skin's two major and synergistic antioxidants — lipid soluble skin-native Vitamin E (1% concentration) and water-soluble skin-native Vitamin C (15% concentration) — which exist at inadequate levels within the skin for optimal photoprotection irrespective of dietary factors, supplemented by the plant-native photoprotective antioxidant ferulic acid.

Skinceuticals C E Ferulic is suitable for normal to dry skin with little to no tendency toward sensitivity.

Individuals with combination or oily skin should use Skinceuticals Phloretin CF instead of Skinceuticals C E Ferulic.

For deeper-penetrating and more firming Vitamin C, and possibly greater UVA protection, use Skinceuticals Serum 20 AOX+, Obagi C Clarifying Serum, Obagi Professional C or IS Clinical Advance+ Serums.

A product containing tocopheryl glucoside such as Glytone Vitaceutical Serum may be used in place of the Vitamin E in Skinceuticals C E Ferulic if you choose to use one of the deeper-penetrating alternatives above.

Note: Products containing Vitamin C (ascorbic acid) can be irritating to some individuals. If you have sensitive skin, commence use with a milder Vitamin C alternative such as La Roche-Posay Active-C or Alyria Antioxidant Capsules which contain 10% and 5% ascorbic acid respectively. To acclimatize skin, commence use with one application every other morning and increase use to once daily as tolerated in a manner as per the instructions for optimizing results from Prevage MD. Introduce more concentrated Vitamin C products such as Skinceuticals C E Ferulic (15% Vitamin C) or Skinceuticals Serum 20 AOX+ (20% Vitamin C) over time if possible.

Skinceuticals C E Ferulic may be combined with or used in rotation with other antioxidants.