Skin Health Skin Care & Cleansing Products Anti-Aging Skin Care What Is the Glogau Classification of Photoaging? Rank your level of sun damage and learn how to prevent wrinkles with sunscreen Print By Heather Brannon, MD Updated September 10, 2018 Getty Images/Dimitri Otis/Photographer's Choice More in Skin Health Skin Care & Cleansing Products Anti-Aging Skin Care Hair & Scalp Care Acne Psoriasis Eczema & Dermatitis Fungal, Bacterial & Viral Infections More Skin Conditions The Glogau classification system was developed to objectively measure the severity of wrinkles and photoaging (the premature aging of the skin, which is usually caused by too much exposure to ultraviolet rays). This classification system helps practitioners pick the most appropriate procedures for treatment. Find out where you rank on the system and learn how to prevent wrinkles and photoaging with sunscreen. Glogau Classification of Photoaging Group Classification Typical Age Description Skin Characteristics I Mild 28-35 No wrinkles Early Photoaging: mild pigment changes, no keratosis, minimal wrinkles, minimal or no makeup II Moderate 35-50 Wrinkles in motion Early to Moderate Photoaging: Early brown spots visible, keratosis palpable but not visible, parallel smile lines begin to appear, wears some foundation III Advanced 50-65 Wrinkles at rest Advanced Photoaging: Obvious discolorations, visible capillaries (telangiectasias), visible keratosis, wears heavier foundation always IV Severe 60-75 Only wrinkles Severe Photoaging: Yellow-gray skin color, prior skin malignancies, wrinkles throughout—no normal skin, cannot wear makeup because it cakes and cracks Exposure to ultraviolet light (either UVA or UVB rays) from sunlight accounts for 90 percent of the symptoms of premature skin aging, including wrinkles. The most important skincare product that's available to prevent wrinkles is sunscreen, but most people do not use sunscreen correctly. Important factors to consider with sunscreen use are: The spectrum of UV radiation that's absorbed by the sunscreen.The amount of sunscreen that's applied. The frequency of application. Type of UV Radiation The sun gives off ultraviolet (UV) radiation that is divided into categories based on wavelengths. UVC radiation: is absorbed by the atmosphere and does not cause skin damage. UVB radiation: affects the outer layer of skin (the epidermis) and is the primary agent that's responsible for sunburns. UVB does not penetrate glass and the intensity of UVB radiation depends on the time of day and the season. UVA radiation: penetrates deeper into the skin and works more efficiently. The intensity of UVA radiation is more constant than UVB, without the variations during the day and throughout the year. Unlike UVB rays, UVA rays can penetrate glass. UV Radiation and Wrinkles Both UVA and UVB radiation cause wrinkles by breaking down collagen, creating free radicals, and inhibiting the natural repair mechanisms of the skin. A popular classification system of sun sensitivity is the Skin Phototype (SPT) classification. People with skin types I and II are at the highest risk for photoaging effects, including wrinkles and skin cancer. The proper use of sunscreen to block both UVA and UVB radiation is an important weapon in the battle against wrinkles. Sunscreen Ingredients Sunscreen ingredients can be divided into compounds that physically block radiation and compounds that absorb radiation. The radiation blockers are very effective at reducing the exposure of the skin to both UVA and UVB radiation. Older formulations like zinc oxide are opaque and may be cosmetically unappealing. However, a newer formulation of micronized titanium dioxide is not as opaque and provides excellent protection. The radiation-absorbing ingredients are differentiated by the type of radiation they absorb: UVA absorbers and UVB absorbers. Picking the Proper Sunscreen The SPF (sun protection factor) of a sunscreen measures the amount of UVB absorption that it provides, but there is no method of reporting how much a sunscreen absorbs UVA. The only way to determine whether a sunscreen protects against both UVA and UVB radiation is to look at the ingredients. A good broad-spectrum sunscreen should have an SPF of at least 15 and contain avobenzone, titanium dioxide, or zinc oxide. Applying Sunscreen Properly Most people use sunscreen improperly by not applying enough. The average person applies only 25 to 50 percent of the recommended amount. Sunscreen should be applied so liberally to all sun-exposed areas that it forms a film when it's initially applied. It takes 20 to 30 minutes for sunscreen to be absorbed by the skin, so it should be applied at least a half an hour before going out in the sun. Sunscreen should also be the last product that's applied on the face since some sunscreens can break down in the presence of water that's contained in water-based foundations and moisturizers. Reapplying Sunscreen Most instructions on sunscreen labels recommend reapplying sunscreen "frequently," but the definition of "frequently" is vague. A common instruction is to reapply sunscreen after two to four hours in the sun. However, one study has shown that reapplying sunscreen 20 to 30 minutes after being in the sun is more effective than waiting two hours. It is possible that this time period is more effective because most people do not apply enough sunscreen initially, and this second application approximates the actual amount needed. Sunscreen should also be reapplied after swimming, excessive sweating, or toweling. Daily Sunscreen Sunscreen should be applied daily. The daily use of a low-SPF sunscreen (like SPF 15) has been shown to be more effective in preventing skin damage than the intermittent use of a higher SPF sunscreen. Sunscreen and Insect Repellents Insect repellents reduce a sunscreen's SPF by up to one-third. When using sunscreen and insect repellent together, a higher SPF should be used and reapplied more often. Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you reach your 2019 goals. Email Address Sign Up There was an error. Please try again. Thank you, , for signing up. What are your concerns? Other Inaccurate Hard to Understand Submit Continue Reading Article What Protects Your Skin Better: Sunscreen or Sunblock? Article How Using Sunscreen Can Help Prevent Sun Damage and Premature Aging Article How Does the Sun Age Your Skin? Article Are Nanoparticles Safe? Why Are They in My Sunscreen? 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