Sebum, a clear waxy substance made of lipids, acts as a natural emollient and barrier. It helps
protect and waterproof hair and skin and keep them from becoming dry and cracked. It can also
inhibit the growth of microorganisms on the skin. Sebum, which in Latin means “fat” or “tallow,” is
made of wax esters, triglycerides, fatty acids, and squalene. The amount of sebum we produce varies
from season to season and can be predetermined genetically, but in fact, the amount of sebum needed
to keep skin moist and healthy is very small. People who are “blessed” with oily skin think their skin
is dripping oil, but they produce only 2 grams of sebum a year!
For some reason, sebum became public enemy number one in the fight for clearer skin. It is just as
absurd as saying that tears should be blamed for smudged mascara! Skin experts claim that sebum
combines with dead skin cells and bacteria to form small plugs in the skin’s pores. The only way to
keep skin clean, they insist, is to completely stop the production of sebum. Instead of promoting good
skin care habits that would eliminate dead skin cells and bacteria buildup, these “experts”
recommend stripping skin of its vital fluid with the drug isotretinoin or “deep” cleansers that wreak
havoc on the skin’s nature-given abilities to cleanse and revitalize itself through cellular turnover and
natural moisturizing.
Sometimes your skin may feel tight and scaly. This is when your skin’s oil barrier loses its
effectiveness, most often due to a cold and dry environment during the winter. Instead of letting skin
readjust itself by producing more sebum, we cover it with a synthetic, oily film that physically blocks
water loss. On top of this film, we may put an additional layer of waxes, petrochemicals, talc, and
dyes in the form of makeup. To remove this airtight layer cake, we treat our skin with ionic
surfactants and detergents that destroy the natural moisturizing factor, leaving the skin more
vulnerable than before. Squeaky-clean is good for kitchen sinks, but not for human skin!
While sebum locks moisture in skin, the natural moisturizing factor (NMF) keeps skin hydrated.
NMF is a mixture of water, free amino acids, lactic acid, and urea, as well as sodium, potassium,
chloride, phosphate, calcium, and magnesium salts that keep the skin moist and supple by attracting
and holding water. The water content of the skin’s outer layer is normally about 30 percent; it rises
after the skin has been treated with certain humectants, such as hyaluronic acid, that boost the skin’s
ability to retain moisture. To help preserve water, skin cells contain fats and fatty acids, which trap
water molecules and provide a waterproof barrier that prevents transepidermal water loss (TEWL).
It is important to feed aging skin with substances that resemble the skin’s own oils.
TEWL is the constant movement of water through the epidermis. Water evaporates through the
epidermis to the surrounding atmosphere. Environmental factors such as humidity, temperature,
season, and the moisture content of the skin can all affect TEWL.
Our skin gets drier as we get older because it loses some of its intercellular lipids after age forty. It
is important to feed aging skin with substances that resemble the skin’s own oils. These moisturizers
should become oilier, but not necessarily heavier, as our skin ages. Essential fatty acids can greatly
help skin retain moisture, and since they are natural, our skin accepts them more happily, which
means less irritation.
Skin Eats, Too!
Advocates of synthetic skin care insist that our skin is virtually watertight. Many say skin can be
scrubbed, steamed, and washed, and nothing penetrates it deep enough to cause any damage. At the