Improvements in our understanding of the biology of skin aging, coupled with increased demand, has led to a plethora of anti-aging skin care products reaching the market over the past ten years. There are now so many products available that it can be overwhelming to the consumer. Knowing a little about the science behind skin care products can help us make informed decisions when we purchase a cream or lotion that claims to have anti-aging properties.
Skin that is aged and damaged by sun exposure undergoes a number of important changes. The most important of these is the decreased production and increased breakdown of collagen and elastin, two key proteins that contribute to the skin's youthful appearance. Ultraviolet (UV) light damages elastic fibers and alters the skin's normal support architecture. Over time, aging and sun exposure result in wrinkling, loss of elasticity (sagging), increased pigmentation and a coarsening of our skin's texture. Our skin also loses its ability to retain moisture, resulting in dryness, cracking and flaking.
The following categories of ingredients have been found to have a beneficial effect on the appearance of aged skin. Ask your dermatologist for a list of products that he or she recommends.
1) Retinoids (Vitamin A Derivatives)
Retinoids (derivatives of vitamin A) are the best-studied and possibly the most effective of all the anti-wrinkle ingredients. Over-the-counter retinoids found in skin care products include retinol, retinal aldehyde and retinyl esters. These are widely available and are well-tolerated. Prescription creams contain retinoids such as tretinoin and tazarotene, which are more potent and are thought to be more effective, but they can be irritating to the skin. Fair-skinned people in particular may have trouble tolerating prescription retinoid creams.
There is ample evidence that vitamin A derivatives in skin care creams can improve the signs of aging. Retinoids lead to thickening of the epidermis (the top layer of the skin), increased smoothness of the skin, increased production of collagen, lightening of hyperpigmentation (discolouration) and lessening of fine wrinkles. Retinoids are degraded by sunlight and should be used at bedtime. They also increase sun-sensitivity and are best used in conjunction with a sunscreen.
2) Antioxidants. Antioxidants are chemicals that fight cell damage from Free radicals. Free radicals are unstable molecules that are produced in our skin by external forces (like sun exposure, pollution or smoking) or internal forces like our normal metabolism or stress. These molecules are highly unstable and can react with our cells' DNA or the cell membrane (the lining around the cells), causing damage or cell death. Free radicals play an important part in skin aging and possibly also in the development of skin cancer.
Antioxidants "mop up" free radials by donating an electron to them, rendering them harmless. Because free radicals are produced after exposure to ultraviolet radiation, antioxidants may work synergistically with sunscreens to protect our skin from sun damage. Some can also lighten skin discolouration and stimulate collagen production. Antioxidants commonly used in skin care products include vitamins C and E.
3) Peptides and Proteins
Peptides are made of up short chains of amino acids, our body's "building blocks". Longer chains of peptides make up proteins. Peptides have been used in anti-aging creams for several years. They are the "messengers" of the body and in laboratory settings they activate cell growth and repair. Most peptides used in skin care products today act by stimulating the production of collagen, elastin and glycosaminoglycans (sugar molecules that help give the skin support).
4) Growth Factors
Growth factors are naturally-occurring substances that mediate signalling within and between cells. They promote repair and regeneration of cells, and have largely been studied in wound healing. They are being incorporated in to anti-aging products because of their ability to stimulate collagen production and inhibit its breakdown.
5) Alpha Hydroxy Acids
Hydroxy acids exfoliate the skin, making it appear smoother and brighter. The alpha hydroxy acid most commonly found in skin care products is glycolic acid, which is derived from sugar cane. It is an excellent exfoliator and is available over-the-counter as partially-neutralized formulations in concentrations ranging from 3 to 20%. In-office glycolic peels are more potent, ranging in strength from 20-70%. Glycolic acid lifts away dead skin cells, reduces unwanted pigmentation, moisturizes the skin and softens fine lines. Its use may increase sensitivity to sunlight and products containing glycolic acid should be used concurrently with sunscreen.