For the increasingly aging population, the quest to look younger has become more important than ever. The anti-aging market is booming and represents the “key growth engine” for the entire skin care industry. Consumers have high expectations for the efficacy of skin care and want to see visible results. Formulating effective anti-aging products requires a thorough understanding of consumers’ cognitive and emotional needs, formulation chemistry, and most of all, the biology of skin aging.1
Perceived age is the marker for facial aging.2 Aging affects the texture and color of skin as well as the shape of the face. Facial skin movement is controlled by complex muscular networks that allow for functions such as eating, breathing, vision or speech in addition to social behaviors that communicate emotions such as facial expressions. These movements are also partially responsible for facial aging.
The Biology of Skin Aging
The process of skin aging is complex and multifactorial, as structural, functional and aesthetic changes happen at a variable rate. It is misleading to consider skin aging as a uniform biological event; several distinct biological processes may occur concurrently.3 There are five types of skin aging, including: intrinsic, extrinsic, lifestyle, hormonal or catabolic.
Intrinsic, chronological aging reflects the passage of time from gravity and genetics. Extrinsic aging is usually attributed to photoaging and smoking. Lifestyle or behavioral aging includes diet, alcohol and drugs. Hormonal aging involves dysfunction or aging of hormonal systems. Finally, catabolic aging is related to chronic diseases. These types will be explained here.
Intrinsic aging: Intrinsic skin aging is a slow process with clinical features such as smooth, pale, dry and less elastic skin having fine wrinkles that are not apparent until old age. Intrinsically aged skin shows epidermal and dermal atrophy, a reduced number of fibroblasts, less collagen and more matrix metalloproteinases (MMPs). Its structurally altered dermal-epidermal junction (DEJ) may contribute to increased skin fragility and reduced nutrient transfer between the dermal and epidermal layers.4
Extrinsic aging: Extrinsic aging, due to chronic exposure to solar ultraviolet irradiation (photoaging) and smoking, leads to deep and coarse wrinkles, mottled hyperpigmentation and reduced skin elasticity. Facial skin bears the accumulation of lifelong sun exposure, which is responsible for 80% of the effects of facial skin aging, i.e., premature skin aging and skin cancer. While photoaged epidermis shows atrophy and abnormal keratinocyte maturation, dermal changes entail accumulation of elastic material (solar elastosis) and loss of elastic fiber integrity. These changes lead to reduced skin elasticity and manifest as wrinkles.
Smoking also accelerates aging, causing the degradation of elastic fibers and a significant increase in facial wrinkles. The wrinkles of smokers are deep and narrow, compared to nonsmokers. This pattern of wrinkling is referred to as “smoker’s face” and often is accompanied by gaunt features and atrophic, gray, uneven skin color.5 Further, pursing the lips and squinting while inhaling smoke may lead to the formation of sharply contoured crow’s-feet and prominent peri-oral lines.
Hormonal and catabolic aging: The skin is a hormone-dependent organ, and the decline of hormonal secretions during menopause accelerates skin aging. Menopause appears as a turning point in life, with a decline in skin qualities.6 Estrogen in particular has a profound effect on skin, encouraging extracellular matrix production and preventing decreases in collagen, skin thickness, skin hydration and epidermal barrier function.7 Increased sagging, as opposed to coarse wrinkles, is the main symptom of postmenopausal aging.8 Catabolic aging compromises older skin further through the impact of a specific chronic disease, such as diabetes, hypothyroidism, cancer or infection.
Anti-aging skin care technologies have become increasingly high-tech, targeting specific cellular phenomena. However, as illustrated above, skin aging is the sum of several concurrent aging processes, which differ in aging contribution among individuals. Photoaging has received more attention in research and the media but is only one aspect of the aging process. Although the rationale for sun protection is widely advocated, people still associate it with occasional holiday exposure.9
Photoaging affects people of the same age and photo-type differently,10 and might not become apparent for decades after the initial damage. To ensure good environmental protection, daily skin care products containing a combination of SPF 20+ and a spectrum of antioxidants should be used.
Postmenopausal skin aging is often neglected in the “classical” aging concept, as its impact is difficult to estimate. In women, intrinsic and postmenopausal aging are linked. There is an array of technologies designed to aid skin changes from intrinsic aging or menopause, e.g., keratinocyte and fibroblast proliferation and repair of the DEJ. Examples of actives clinically tested, although on forearms and not facial skin, include c-xyloside, which was shown to repair the DEJ,11 and bifidobacterium-fermented soy milk extract, which improved skin elasticity.12 In the absence of advanced diagnostics, preventive measures should target each of these processes.
Skin aging is an interplay of the different types of aging that differs between individuals; the best approach entails the use of multifunctional active ingredients that address more than one type. Also, shifting consumer attitudes toward a more holistic approach to skin health represents the next educational challenge for the skin care industry.
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1. Anti-aging, in-cosmetics 2013, www.in-cosmetics.com/en/sessions/1325/anti-aging (Accessed Mar 10, 2013)
2. DA Gunn et al, Why some women look young for their age, PLoS ONE 4(12) e8021, doi:10.1371/journal.pone.0008021, www.plosone.org/article/info:doi/10.1371/journal.pone.0008021 (Accessed Mar 10, 2013)
3. P Quatresooz, C Piérard-Franchimont, M Kharfi, K Al Rustom, CA Chian, R Garcia, MR Kamoun, GE Piérard, Skin in maturity: The endocrine and neuroendocrine pathways, Int J Cos Sci, 29(6) (2007) 1–7, http://onlinelibrary.wiley.com/doi/10.1111/j.1467-2494.2007.00350.x/full (Accessed Mar 10, 2013)
4. AK Langton, MJ Sherratt, CE Griffiths and RE Watson, A new wrinkle on old skin: The role of elastic fibres in skin aging, Int J Cosmet Sci (2010) www.ncbi.nlm.nih.gov/pubmed/20572890 (Accessed Mar 10, 2013)
5. D Model, Smoker’s face: An underrated clinical sign? Br Med J (Clin Res Ed) 291(6511) 1760–1762 (Dec 21–28 1985) www.ncbi.nlm.nih.gov/pubmed/3936573 (Accessed Mar 10, 2013)
6. C Piérard-Franchimont, F Cornil, J Dehavay, F Deleixhe-Mauhin, B Letot and GE Piérard, Climacteric skin ageing of the face—A prospective longitudinal comparative trial on the effect of oral hormone replacement therapy, Maturitas Jun 21 32(2) 87–93 (1999), www.ncbi.nlm.nih.gov/pubmed/10465376 (Accessed Mar 10, 2013)
7. MG Shah and HI Maibach, Estrogen and skin. An overview, Am J Clin Dermatol 2001 2(3) 143–150, www.ncbi.nlm.nih.gov/pubmed/11705091 (Accessed Mar 10, 2013)
8. GE Piérard, The quandary of climacteric skin aging, Dermatology 193(4) 273–274 (1996), www.ncbi.nlm.nih.gov/pubmed/8993948 (Accessed Mar 10, 2013)
9. G Nole and AW Johnson, An analysis of cumulative lifetime solar ultraviolet radiation exposure and the benefits of daily sun protection, Dermatol Ther 17 Suppl 1:57–62 (2004) www.ncbi.nlm.nih.gov/pubmed/14728700 (Accessed Mar 10, 2013)
10. GE Piérard, Skin ageing, a fresh look at an old story, J Cosmet Dermatol Jan 3(1) 1 (2004), www.ncbi.nlm.nih.gov/pubmed/17163940 (Accessed Mar 10, 2013)
11. C Deloche, AM Minodo, BA Bernard, F Bernerd, F Salas, J Garnier and E Tancrède, Effect of c-xyloside on morphogenesis of the dermal epidermal junction in aged female skin. An ultrastructural pilot study, Eur J Dermatol Mar–Apr 21(2) (2011)
12. K Miyazaki, T Hanamizu, T Sone, K Chiba, T Kinoshita and S Yoshikawa, Topical application of Bifidobacterium-fermented soy milk extract containing genistein and daidzein improves rheological and physiological properties of skin, J Cosmet Sci Sep–Oct 55(5) 473–479 (2004)