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Alpha hydroxy acids have been an ongoing craze of skincare industry for several years, although their cosmetic use has started several decades ago. They are a group of structurally related organic acids found in natural sources or synthesized in the laboratory. Before we go any further, it should be noted that skincare products based on alpha hydroxy acids are often ridiculously overpriced. Alpha hydroxy acids are very simple, inexpensive chemicals. The cost of alpha hydroxy acids contained in a typical jar of alpha hydroxy acids-based cosmetics is a fraction of a dollar. The effectiveness of an alpha hydroxy acids skincare product depends mainly of the concentration of alpha hydroxy acids rather than accompanying inactive ingredients with scientific-sounding names. Provided alpha hydroxy acids concentrations are the same, an affordable department store brand would bring the same skin benefits as its overpriced counterparts. There are two different ways in which alpha hydroxy acids are commonly used: (1) high strength alpha hydroxy acids are used by dermatologists in chemical peels. Several studies convincingly demonstrated that such peels can reverse some signs of skin aging. In a 1996 study at the University of Los Angeles, California, forty five volunteers were treated with 50 percent glycolic acid or vehicle alone. The treatment was applied to one side of the face, forearms and hands for 5 minutes once weekly for 4 weeks. The researchers concluded that "application of 50 percent glycolic acid peels improves mild photo aging [aging due to sun damage] of the skin." Another study conducted at Hahnemann University School of Medicine, Philadelphia, Pennsylvania, tested a lotion containing 25 percent of glycolic, lactic or citric acid against a placebo lotion. The treatment was continued for 6 month. Alpha hydroxy acids treatment lead to a 25 percent increase in skin thickness, improved quality of elastic fibers and increased density of collagen. The researches concluded that alpha hydroxy acids "produced a significant reversal of epidermal and dermal markers of photo aging." Peels with high strength alpha hydroxy acids (over 15%) should not be done without the supervision of a dermatologist. These days the most common use of alpha hydroxy acids is in OTC skincare products formulated for regular use. Most such products contain relatively low concentrations of alpha hydroxy acids, usually 5-15 percent. Benefits of these skincare products are less clear. Products with alpha hydroxy acids concentration below 8% appear to be of no benefit. Most studies of 8 - 15% alpha hydroxy acids report very modest improvements in wrinkles and skin smoothness. Concentrations at the high end of this range might be a little more effective but are more likely to cause irritation. Just as alpha hydroxy acids, beta hydroxy acids are simple organic acids found in nature or synthesized in the laboratory. They are somewhat different from alpha hydroxy acids in structure and mode of action. Although beta hydroxy acids are now often portrayed as the latest skincare breakthrough, they have been around for quite a while. Salicylic acid, a common beta hydroxy acids, has been used for treating acne for decades. In fact, acne treatment remains the use of choice for beta hydroxy acids. There are no studies showing that beta hydroxy acids are superior or even equal to alpha hydroxy acids for skin exfoliation, reducing fine wrinkles, etc. For acne, however, beta hydroxy acids are clearly superior to alpha hydroxy acids. For persons without acne, adding beta hydroxy acids to alpha hydroxy acids regimen is a waste of money. Main benefits of alpha hydroxy acids come from their ability to exfoliate skin. Removal of the outermost layer of the skin stimulates the cells in lower layers to grow and divide, causing the skin to thicken and thus diminishing visible signs of aging. The more you exfoliate the more cell divisions will occur in the lower skin layers. There is one problem though. Normal human cells cannot divide indefinitely. Fibroblasts (a key type of cells in the skin) would divide about fifty times and then enter a so-called stage of senescence. This limit of about fifty cell divisions is called the Hayflick limit (after its discoverer, Dr. Leonard Hayflick). This is a state in which the cell is sluggish, inefficient, unresponsive to various signals from the body and unable to divide. Skin with many senescent cells is usually fragile blotchy and easily wrinkled. Exfoliation remains a valuable cosmetic tool but if you overuse it, your skin may "hit the Hayflick limit" earlier than it should. In recent years, researchers have discovered the molecular mechanism of the Hayflick limit. (It has to do with the areas at the tips of chromosomes called telomeres). Medical technologies to eliminate the Hayflick limit may appear in a reasonably near future. These technologies are likely to work only for those cells whose Hayflick limit has not yet been reached. Today's good news is that Hayflick limit does not appear to be carved in stone. Research indicates that very simple measures available today may help extend it by as much as 50 percent. (Further details are included in the Skin Rejuvenation Infopack ). |
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