Your skin maintains body temperature, acts as a defense against microorganisms, and protects you from harmful sunlight and irritating substances. Its most important function, however, is to serve as a barrier against water and electrolyte losses, which is essential to the preservation of life. To work effectively, the barrier requires that the outer layer of your skin retain water content at about 20 to 30 percent. When the water levels decrease to about 10 percent, the skin becomes dry and scaly and rough texture becomes apparent.
Water escapes from the skin at a rate of one pint per day which makes it dry. You lose more water when you perspire, when the climate is dry, and when you advance in age, as aging skin partially loses its ability to hold in water. Dry skin also results from frequent exposure to irritating substances like detergents and chemicals. Long periods of water exposure, frequent scrubbing with exfoliants and repeated application of rubbing alcohol strip the skin of its natural oils (called lipids by doctors), causing water to escape.
Dr. Grace Garcia and Dr. Evangeline Handog, dermatologists of the Asian Hospital and Medical Center, said that the loss in moisture and disruption of the skin’s natural lipids create a need for the use of a moisturizer as part of daily skin care. The only exception to this rule probably applies to people with very oily skin.
Moisturizers may be classified generally as either barriers or binders. Barriers work by forming a long lasting film that serves as a wall that prevents loss of water. These substances stay on top of the skin and are frequently composed of a combination of oil and water. Some barriers fill spaces in between skin cells, thereby smoothing and lubricating the surface. These non-oil molecules sink into the skin, helping to replace lipids and allowing repair to occur underneath.
In barriers containing oil, the products differ according to the ratio of oil in relation to water. Oil based barriers have only a small amount of water dissolved in oil. On application, they leave the skin with a greasy feel. Water based formulations are mostly water in content and feels light on the skin. However, it has little staying power compared to its oily cousins.
Most creams and lotions in the market are water based. Drs. Garcia and Handog explained that if you do not know whether a product is water-based or oil-based, here’s a good tip. Put on the moisturizer. If the skin where you applied it is warm, it is oil based. If cool, it is water based. The reason for this is that water evaporates from the skin and is cooling, while oil traps water and consequently heats up skin.
Four different oils can be found in moisturizers: (1) vegetable oil; (2) animal oil; (3) mineral oil; (4) Vitamin E oil or tocopherol. Many plants are sources of oil for moisturizers. You can recognize them by their names: lemon, coconut, corn, avocado, olive, macademia, sunflower, peanut, jojoba, and many more. They are generally equal in their ability to moisturize skin. Animal oils include lanolin from sheep’s wool and fish oil. Mineral oil comes from petroleum (the good old petroleum jelly and mineral oil) or sand and rock (cyclomethicone, dimethicone). The latter are lighter on skin but are much more expensive than those coming from petroleum. Vitamin E is also a good moisturizing oil.
Non-oil based barriers work by imitating the skin’s natural lipids. Common ingredients are collagen, elastin, lecithin, sodium hyaluronate, animal fats such as cholesterol, glycolipids and ceramides, the most abundant lipid in the skin.
On the other hand, binders work by drawing in water from the environment and lower regions of the skin. They are also called humectants by doctors. They may be used in “oil-free” moisturizers used for acne-prone skin. Binders are also used in many diseases of the skin that are thickened as they cause softening when applied. Examples of humectants include urea, glycerin, sorbitol, alpha hydroxy acids like glycolic and lactic acids, sugars, propylene glycol and others.
Most moisturizers would contain a mixture of barriers and binders, or even several substances within the same class. The best moisturizer for you would depend on the particular needs of your skin for the moment. Normal skin can be maintained with a water based moisturizer that has a light non-greasy feel. Dry skin as well as aging skin will benefit from a heavier, oil based moisturizer. Oily skin is best applied with an oil-free, water based product. For best advice, consult only a Board-certified dermatologists and not the one who cuts or shave your hair nor the one who does your facial in salons or barbershops. --- Photo from the Internet.