Ascorbyl palmitate is a stable, lipid soluble form of vitamin C that is used in skin care products for its ability to protect the skin from free radicals, stimulate collagen production, and reduce hyperpigmentation.
Vitamin C is a naturally occurring antioxidant that is synthesized by most plants and animals from glucose. Humans lack the enzyme (L-glucono-gamma lactone oxidase) required to produce vitamin C, which means it must be acquired from dietary sources. Vitamin C is necessary for normal growth, development, and repair of damaged tissues in the body, as well as the enzymatic production of certain neurotransmitters. It is also important for immune system function.
Vitamin C is the most abundant antioxidant in human skin. After oral intake of vitamin C, however, the absorption in the gut is limited by an active transport mechanism. This means that no matter how much vitamin C you ingest only a finite amount can be absorbed. Further, the bioavailability of vitamin C in the skin is inadequate when it is administered orally. Therefore, we rely entirely on external supplementation, such as topical application in the case of cosmetics.
Vitamin C is available in a number of active forms. One is ascorbyl palmitate, an ester formed from ascorbic acid (pure vitamin C) and palmitic acid (a saturated fatty acid). The result is a lipid (fat) soluble form of vitamin C. The functions of ascorbyl palmitate will be discussed below. The most biologically active form of vitamin C, however, is L-ascorbic acid. While L-ascorbic acid can be used in topical products, its use its limited because it is highly unstable and causes the most skin irritation out of all the forms of vitamin C.
In cosmetics and personal care products, ascorbyl palmitate functions as an antioxidant that can protect the skin from free radicals, stimulate collagen production, and reduce hyperpigmentation.
Ascorbyl palmitate has vitamin C activity approximately equal to that of L-ascorbic acid. However, since ascorbyl palmitate is lipid soluble, it can penetrate the skin better than L-ascorbic acid and other water soluble forms of vitamin C. Unlike L-ascorbic acid, it does not readily degrade in formulas containing water. The optimal pH of formulations containing ascorbyl palmitate is 5.5.
Ascorbyl palmitate functions as an antioxidant, which means it is capable of protecting the skin from free radicals and reactive oxygen species (ROS). Free radicals are generated from external factors such as UV light, smoking, and pollution. Vitamin C neutralizes free radicals by a process of electron transfer and/or donation. This is important because the harmful effects of free radicals occur as direct chemical alterations of the cellular DNA, the cell membrane, and the cellular proteins, including collagen. When collagen within the skin is damaged, signs of premature aging can appear, such as wrinkles, lines, and sagging skin. Therefore, the ability of ascorbyl palmitate to protect collagen makes it an ideal ingredient to include in anti-aging skincare products.
Ascorbyl palmitate is also used as a skin-lightening agent to treat hyperpigmentation, the appearance of dark spots on the skin. It interacts with copper ions at tyrosinase-active sites and inhibits the action of the enzyme tyrosinase, the main enzyme responsible for the conversion of tyrosine into melanin, thereby decreasing melanin formation. By decreasing the synthesis of melanin, the appearance of dark spots is reduced.
Ascorbyl palmitate also improves the elasticity of the skin and reduces wrinkles by stimulating collagen synthesis. Suzan Obagi, assistant professor in dermatology at the University of Pittsburgh, explains to Scientific American, “After the age of 20, a person produces about 1 percent less collagen in the skin each year. As a result, the skin becomes thinner and more fragile with age.” Therefore, by increasing the production of collagen, ascorbyl palmitate can help to keep the skin strong, firm, and less susceptible to wrinkle formation.
The safety of ascorbyl palmitate has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. In clinical studies, ascorbyl palmitate caused no dermal irritation or sensitization. The Panel reviewed the scientific data and concluded that this ingredient was safe for use in cosmetic and personal care products.
References: Wikipedia, “Vitamin C”, Wikipedia, “Ascorbyl Palmitate”, Indian Dermatol Online J. 2013 Apr-Jun; 4(2): 143–146, AAPS PharmSciTech. 2010 Sep; 11(3): 1485–1492, Int J Toxicol. 1999, 18(3) 1 – 26, H&PC Today, 2014, 9(1), J Clin Aesthet Dermatol. 2017;10(7):14–17.