Skin care product layering affects efficacy and outcomes of regimens

The role of eye products

Eye products treat issues such as dryness, puffiness, fine lines, and dark circles. However, they also play an overlooked role of protecting the thin delicate eye area from the treatment product. Using an eye product, especially one with protective ingredients such as barrier repair lipids, will help the patient tolerate the potentially irritating treatment product that follows the eye product. At night, the treatment product ingredients can get on the pillowcase and transfer to the upper and lower eyelids. Use of a protective eye product before bedtime can prevent the accompanying irritation. For example, acne patients often develop redness at the corners of the eyes when using benzoyl peroxide or a retinoid at night. Applying these medications after an eye cream can reduce this side effect.

Improving efficacy of treatment products

Treatments products are defined as corrective products targeted to skin issues such as acne, rosacea, melasma, dryness, skin cancer, eczema, psoriasis, and photoaging. The entire skin care regimen should be designed to enhance efficacy and decrease side effects of the treatment products. Treatment products may be cosmeceuticals, OTC medications, or prescription medications. These products must be able to reach their target in the proper chemical structure to be effective. Each ingredient has various constraints and quirks that should be considered. One well known example is ascorbic acid (vitamin C). Ascorbic acid is a treatment product for skin pigmentation and skin aging that is well known to have specific needs to work properly. Sheldon Pinnell, MD, led multiple investigations demonstrating that the maximum absorption of ascorbic acid occurs at a pH of 2-2.5. He showed that ascorbic acid products should be formulated at a pH of 2-2.5.⁴ However, applying these on skin that has just been cleansed with a soap cleanser with a pH of 9 will raise the skin’s pH and decrease the absorption of ascorbic acid. Having the patient cleanse with a low pH cleanser such as salicylic or glycolic acid cleanser (usually a pH of 2.5-3.5) will lower the pH of the skin and promote absorption of vitamin C.

The role of moisturizers

Moisturizers have many duties, including hydrating the skin, protecting the skin, and delivering important ingredients to the skin. However, moisturizers have a less discussed role of improving the efficacy of the treatment product that is applied beforehand. Moisturizers often contain oleic acid, hyaluronic acid, or other fatty acids that can increase penetration of other skin care ingredients. In addition, many moisturizers provide an occlusive effect that helps increase penetration. They also help protect the underlying treatment product from getting wiped off on a pillowcase or into the environment. In other words, moisturizers “seal in” the treatment product. Some moisturizing ingredients such as heparan sulfate may affect how well the skin cells “hear” and respond to signals elicited by the treatment products. For this reason, moisturizers should also be chosen to improve the efficacy of the treatment product.

Retinoids

When using retinoids for the first time in a patient, applying them last on top of the moisturizer can reduce the incidence of side effects and increase compliance. Retinoids, unlike other ingredients, penetrate easily into the deeper layer of the epidermis. Layering them on top of a moisturizer can help titrate retinoid absorption. The moisturizer can be chosen to slow or increase penetration of retinoids. Retinoids should always be used at nighttime because many of them, especially retinol and tretinoin, are easily broken down by ultraviolet light exposure.