Retinol is a substance that is derived from vitamin A, a nutrient found in a variety of foods, including green leafy vegetables, sweet potatoes, squash, peppers and cantaloupe. When a food that contains vitamin A is ingested, the body breaks down the nutrient into components. One such product manufactured by the digestion of vitamin A is retinal or retinaldehyde. This substance is then further broken down in the body to produce retinol.
The discovery of vitamin A occurred in 1913 when two biochemists, Elmer McCollum and Marguerite Davis, found evidence of the presence of the nutrient in samples of butter fat. Vitamin A was first isolated by two Dutch scientists, David Adriaan van Dorp and Jozef Ferdinand Arens, in 1947. Once vitamin A was able to be isolated for further testing, clinical research about the function of the vitamin and its derivatives like retinol began.
In the human body, retinol performs a variety of important functions. It is a vital component to the pigment that makes it possible for the eyes to see at night and is a building block for the cells that line the organs. Retinol and other components of vitamin A are necessary for the immune system cells that defend the body from bacteria and other foreign substances to function properly. Clinical evidence also suggests that retinol may assist with the production of red blood cells.
When applied to the skin, retinol offers a number of benefits, and as a result, is widely used as an ingredient in skin care products. For commercial use, retinol is manufactured in laboratories by combining chemicals that contain the components of the nutrient. Pure retinol is a very volatile chemical and can be affected by oxygen. As a result, it must be stored and shipped at cold temperatures in special packaging that does not allow the air to reach the ingredient. This makes producing retinol and using it as a skin care ingredient expensive.
To help mitigate some of these costs, retinol can be combined with chemical compounds known as esters. The presence of these additional molecules helps to stabilize the retinol. When a formula contains retinol that is combined with stabilizing esters, the term "retinyl palmitate" is typically featured on the product's list of ingredients. Retinyl palmitate offers many of the same benefits as retinol, but typically takes longer to produce results or requires a larger dosage to completely offer the same level of effectiveness as pure retinol.
Retinol is highly effective for use in skin care products because its molecules are extremely small in size. This allows the ingredient to fully penetrate the outer layer of skin called the epidermis and reach the middle layer of skin called the dermis. The cells of the epidermis are mostly dead tissue, while the lower dermis layer consists of living cells. By delivering ingredients to these cells, retinol is able to produce more noticeable results than other ingredients that affect only the epidermis.
Inside of the dermis, retinol has the potential to support the production of elastin and collagen, structural proteins that prevent the skin from developing fine lines and wrinkles. For this reason, retinol is often found in anti-aging skin care products that are meant to minimize symptoms associated with aging and reduce the appearance of lines and wrinkles.
Retinol also helps to stimulate the cellular turnover process, the natural shedding of the cells of the epidermis that reveals the newer cells of the dermis. This action of retinol provides additional benefits for those battling signs of aging, as promoting the shedding of cells can make deep furrows shallower and less noticeable.
For individuals suffering from hyperpigmentation of the skin, retinol can help eliminate the discolored cells. This makes retinol a popular ingredient in skin brighteners and treatments for melasma and age spots.
Retinol is similar in structure to the prescription medication tretinoin, which is used for treating acne. By removing excess skin cells from the face, tretinoin reduces the amount of clogging that occurs in the pores, allowing acne blemishes to eventually heal. Although the ingredient is not as powerful as tretinoin, retinol offers similar benefits to acne sufferers. In fact, doctors often recommend skin care products that contain retinol to acne sufferers who cannot use tretinoin due to skin sensitivity.