Dipalmitoyl hydroxyproline is a naturally derived ingredient often found in anti-aging skin and lip care products due to its protective effects on collagen and elastin.
Dipalmitoyl hydroxyproline consists of two palmitic acids attached to hydroxyproline, an amino acid. In 1902, Hermann Emil Fischer isolated hydroxyproline from hydrolyzed gelatin. Hydroxyproline is a major component of the protein collagen and plays a key role in collagen stability. It is produced by hydroxylation of the amino acid proline, a process that requires ascorbic acid (vitamin C). In humans, a deficiency in ascorbic acid leads to symptoms of scurvy due to the resulting defect in hydroxylation of proline residues of collagen.
Collagen is the most abundant protein in the human body. It is the major component of connective tissues that make up several body parts, including tendons, ligaments, muscles, and skin. Collagen plays a role in strengthening skin, plus may benefit elasticity and hydration. The collagen protein is composed of a triple helix with three amino acids: hydroxyproline, proline, and glycine.
Dipalmitoyl hydroxyproline is found in anti-aging skin and lip care products because it can reduce signs of aging through multiple mechanisms.
One way that dipalmitoyl hydroxyproline reduces signs of aging is by stimulating the synthesis of collagen. This is important since the body produces less and less collagen with age. 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.” Moreover, environmental free radicals can degrade collagen proteins. The result is skin that becomes thinner and more fragile with age.
After topical application, dipalmitoyl hydroxyproline is absorbed through the skin where it plays specific and essential roles in the synthesis of collagen sub-units and in the three-dimensional folding of collagen fibers. The result is stronger, more plump skin that is less susceptible to wrinkle formation.
Another way that dipalmitoyl hydroxyproline functions to reduce signs of aging is by preserving elastin fibers through anti-elastase activity. Elastin is a highly elastic protein found within the skin that allows the skin to resume its shape after stretching or contracting. While collagen makes skin look plump, elastin allows the skin to be elastic, pliable, and firm. Unfortunately, enzymes known as elastases within the skin break down elastin, which leads to wrinkle formation. Therefore, through its anti-elastase activity, dipalmitoyl hydroxyproline can help to reduce signs of aging and maintain skin elasticity.
Lastly, dipalmitoyl hydroxyproline functions as an antioxidant, which means it is capable of protecting the skin from free radicals and reactive oxygen species (ROS). Environmental free radicals are generated from factors such as UV radiation, smoking, pollution, etc. The harmful effects of free radicals occur as direct chemical alterations of the cellular DNA, the cell membrane, and the cellular proteins, including collagen and elastin. As mentioned above, damage to collagen and elastin causes the skin to lose strength and elasticity, resulting in lines, wrinkles, and sagging skin. Therefore, the ability of dipalmitoyl hydroxyproline to protect collagen and elastin from free radical damage makes it an ideal ingredient to include in anti-aging skin care products.
There is little data available on the safety of dipalmitoyl hydroxyproline as used in cosmetics and personal care products. According to EWG’s Skin Deep Cosmetic Database, dipalmitoyl hydroxyproline is rated as a 1 on a scale of 1 to 10, with 1 being the lowest risk to health and 10 being the highest.
References: Wikipedia, “Hydroxyproline”, Photochem Photobiol. 2001 Aug;74(2):283-90., Ingredients to Die For, “LiPlump”, EWG’s Skin Deep Cosmetic Database, “Dipalmitoyl Hydroxyproline”.