The range of reactions varied widely from swelling around the eyes, red blotches on the face, and overall dullness. Measurements taken using three-dimensional imaging showed an overall drop in skin health between 10 to 20 percent. Moisture levels in skin dropped by five to 10 percent. In other words, leaving makeup on overnight aged skin by years.

Not taking off makeup may not seem to be a big deal, but in-depth research on skin health and function shows otherwise. The skin is the largest organ of the body and serves the important function of protecting us from the outside world. One of the things we understand is the science of chronobiology – which is the study of the skin’s circadian rhythms. The skin functions during the day in protective mode; the outer protective layer called the moisture barrier stays at a pH of 5.4. This is extremely important since the protective microflora and defensive immune cells function optimally at this pH level.

Sebaceous glands produce sebum, which travels to the surface of the skin to provide further protection by producing the protective antioxidant, vitamin E, as part of the natural protection factor. Sebum production is highest between the hours of noon and 5 p.m., when ultraviolet exposure is highest. During the rest of the day, the skin is bombarded by environmental pollutants such as vehicle exhaust, cigarette smoke, and more.

The outermost layer to touch the skin is makeup. Keeping it on while sleeping has some very negative results. First, it is important to understand the importance of the skin’s function as we sleep and the importance of getting quality sleep. During the night, skin has the chance to benefit from the increase in blood flow since other systems are not active. So while sleeping, the skin goes into renewal mode, which means the pH is slightly lower than the daytime – approximately 4.9. Other changes include an increase in the microcirculation, which is a way of getting rid of the waste materials that accumulate during the day. Part of this process includes transepidermal water loss. These processes are essential in order for the skin to restore its healthy moisture barrier and rebuild its defensive microflora. Wearing makeup to sleep interferes with the skin’s renewal process. Makeup also continues to break down on the skin, causing more stress on the skin and increased aging. As the moisture barrier is unable to be fully repaired, the incidence of skin sensitivity increases and aging is accelerated.

So mothers were right when they said to wash the face at night before getting that needed beauty sleep. Make sure you advise your clients of these risks and the importance of removing all makeup before bed.