Lauren A. Thaman
P&G Beauty, Sharon Woods Technical Center, Cincinnati, Ohio, U. S.A.
The cosmetic industry has changed dramatically over the past 20 years with the introduction of daily UV lotion in the late 1980s to fight future aging. No longer are women searching for hope in a jar but focusing on the latest over-the-counter breakthrough products with clinically demonstrated biological activity. This quest for skin health and youthful beauty has driven many consumers to explore a variety of approaches. It has also triggered a renaissance in the world of skin care where health, beauty, and technology are converging to create new and exciting opportunities.
This frantic search for beauty and youth has stimulated a remarkable growth in the skin care industry. Skin care advances are moving quickly as they mirror advancing technology in pharmaceuticals and biotechnology. Global retail sales of anti-aging skin care products have increased 71% since 2000 (1). In 2004 skin care sales topped $12 billion, with $7 billion of that being spent on facial treatments alone (2). As biotechnological and pharmaceutical research continues to result in technologic advances, skin care companies will continue to spend millions of dollars on incorporating these advances into skin care products. The average woman will find more choices to aid her in the battle against aging, including customized products and new novel ingredients with increased effectiveness and more precise delivery.
Clearly cosmeceuticals are the fastest growing segment of the skin care market (3) and are currently the driving force in the field of skin care research (4). Cosmeceuticals are cosmetics that contain biologically active ingredients, and while these ingredients are not classified as drugs, they do have documented functional treatment benefits. When cosmeceuticals are labeled and marketed as cosmetics, they are not regulated by the FDA.
Cosmeceuticals are used primarily to combat the effects of aging on the skin. More women are yearning for healthy, youthful skin, fueling the demand for these anti-aging products. Younger women are also looking to these products as a preventive strategy against aging. Cosmetic companies are investing millions of dollars to develop new and
better actives for anti-aging products, and women of all ages are constantly trying the newest product and consulting their dermatologists for therapeutic approaches to fight the signs of aging.
Retinoids are the most recognized anti-aging ingredient, comprising a family of compounds with structures and mechanisms of action that resemble those of vitamin A. Retinoids are essential nutrients which play a role in cell growth and differentiation (5). Tretinoin, the most popular retinoid, increases dermal collagen, cellular differentiation, and proliferation. It has been shown to improve skin’s global appearance, particularly affecting fine and coarse wrinkling, roughness, pigmentation, and sallowness (6,7). However, tretinoin is a drug regulated by the FDA. Retinol, first generation retinoid, is often added to over-the-counter cosmetics (8). Retinol must be converted to retinaldehyde and then to all – trans-retinoic acid within the keratinocyte to become active (9). Because retinol is a cosmetic ingredient, it is not labeled as an active ingredient. While not labeled as such, many published studies demonstrate the significant biological action and efficacy of this cosmetic vitamin A derivative. Retinoids and other alternate metabolisms of vitamin A will continue to be key mainstay cosmeceutical ingredients.
Another popular cosmeceutical affecting cellular proliferation is alpha-hydroxy acid (AHA). AHAs increase the type I collagen, mRNA, and hyaluronic acid content of the epidermis and dermis (3). They also renew the stratum corneum by promoting desquamation. Glycolic acid, lactic acid, and malic acid are all examples of AHAs. Newer generation polyhydroxy acids are also being studied; these PHAs provide additional moisturization compared to AHAs, and do not cause the irritating response associated with AHAs (10). They also possess antioxidant properties (10).
A major class of cosmeceutical ingredients is antioxidants that mediate free-radical damage from UV radiation. Since the skin’s own supply of free-radical scavengers is limited, topical antioxidants, which scavenge free radicals and protect cells from damage, can attenuate skin damage from UV radiation. Topical antioxidants include vitamins C and E, alpha-lipoic acid (ALA), and coenzyme Q10. In addition to their antioxidant effects, these agents all have other documented anti-aging properties. Vitamin C has collagen stimulating properties and has been shown to be photoprotective (4). Vitamin E decreases free-radical production as well as inhibits collagenase production (11). ALA is a strong intracellular free-radical scavenger (12). It also has anti-inflammatory action, inhibiting the production of pro-inflammatory mediators (3). Coenzyme Q10 (ubiquinone) is present in every cell in the body and acts as a coenzyme in energy production. It has also been shown to improve skin texture (13). One of the bigger challenges to the future use of antioxidants is assuring biological activity from a cosmetic preparation and measuring the antioxidant benefit in a clinical environment. As these challenges become resolved, a significant increase in use and benefit of these ingredients is expected.
The renewed focus on health in today’s society has also created a niche for natural and organic products. Women are interested in natural ingredients that make therapeutic claims. This has led to increased popularity of skin care products containing plant or mineral ingredients, especially in the spa market. Organic advocates are willing to pay extra for skin care products that are clearly organically produced (14). Therefore, one of the hottest areas for cosmeceutical ingredients is the utilization and understanding of botanicals. Topical botanicals have been shown to combat reactive oxygen species, as well as often having various secondary effects. Some strong botanicals include tetrahydro- curcumin, pycnogenol, silymarin, and soy extracts (15). The usage of botanicals for their anti-inflammatory function continues to grow. Botanicals have been shown to block inflammatory changes that may result in cutaneous aging. Some common antiinflammatory botanicals include aloe vera, green tea, and allantoin (15). However, some
newer research suggests the molecular structure, as well as the formulation delivery system, strongly affects the biological activity of botanicals. Understanding the effect and potential of botanicals as cosmeceutical ingredients will likely continue to be a key industry focus.
There are several different types of growth factors of both plant and animal origin that have been incorporated into cosmeceuticals. Furfuryladenine (kinetin), a synthetic plant growth factor that delays senescence of plant cells, has shown in vitro benefits in retarding cellular aging (16). Transforming growth factor-beta 1 is an important human growth factor with therapeutic potential because of its role in neocollagenesis (3). Human growth factors are relatively under explored by the cosmetic industry today and given the negative public view associated with this class of ingredients it is unlikely that they will be a top focus area in the coming years.
Stimulating the skin’s natural repair and rejuvenation system by topically adding skin functional ingredients like peptides, hyaluronic acid, niacinamide (vitamin B3), estrogen, and dimethylaminethanol will continue to show promise in improving the appearance and texture of skin. Delivering these relatively large molecules to the biological key targeted area to maximize the effect remains the key barrier to skin aging damage reversal or stimulation. Research in this area will continue with the next wave of cosmeceutical ingredient breakthroughs.