INTRODUCTION
Photo-aging is characterized by sagging and thinning of the skin, discoloration, fine lines, and skin fragility. It is mainly induced by sun exposure, including UVA and UVB rays. Clinical signs of photo-aging are caused by loss of elastin, hyaluronic acid (HA), and collagen. Loss of elastin tissues leads to skin sagging resulting in nasolabial fold (NL) wrinkles, sagging of the jaw line, and crow’s feet wrinkles. Loss of collagen in skin leads to fine lines, thinness, fragility, and textural change. Loss of hyaluronic acid in skin results in decreased skin plumpness and fine lines.
Protection against UV exposure helps prevent or minimize many of the visible signs of aging. The American Academy of Dermatology recommends daily use of a broad-spectrum sunscreen with a minimum SPF of 30. While many consumers recognize the need for sunscreen, many are challenged by the smell or feel of sunscreens, resulting in non-compliance and loss of sun protection. Hence, a broad-spectrum sunscreen with high user appeal is critical to any anti-aging solution.
Collagen levels can be increased by using topical alpha hydroxy acids, retinoids, and vitamin C.1 Vitamin C has the added benefit of improving skin tone and color and providing antioxidant benefits in addition to its ability to increase collagen production. As humans are unable to synthesize vitamin C, thus the intake of dietary supplements or application of topical formulations of vitamin C is necessary to delay the process of aging or diseases related to vitamin C deficiency. Vitamin C is commonly used to treat aged skin because of its regenerative effects on skin texture, color, and inflammation through its roles as an antioxidant, tyrosinase inhibitor, and inducer of collagen synthesis.
Hyaluronic acid is composed of repeated units of sugars (saccharides). The size of the HA molecule determines the ability of topically applied HA to penetrate into the skin.1 Hyaluronic acid that is applied to the surface of the skin is a humectant; therefore, it draws water into itself, which can increase skin hydration in a humid environment. Hyaluronic acid applied topically is typically used in the smaller molecular size form of sodium hyaluronate, a sodium salt of hyaluronic acid.
Vitamin C is one of the most recognized antioxidants in consumer surveys and has had a surge in popularity over the last 10 years with many topical products entering the market making it difficult for the products to differentiate themselves to consumers. This study investigates two commercially available topical vitamin C and sunscreen products.