  a wrinkle, also known as a rhytide, is a fold, ridge or crease in the skin. skin wrinkles typically appear as a result of aging processes such as glycation, habitual sleeping positions, loss of body mass, or temporarily, as the result of prolonged immersion in water. age wrinkling in the skin is promoted by habitual facial expressions, aging, sun damage, smoking, poor hydration, and various other factors.anderson, laurence. 2006. looking good, the australian guide to skin care, cosmetic medicine and cosmetic surgery. ampco. sydney. isbn 0-85557-044-x. ==treatments for aging wrinkles== thumb|right|wrinkles on the face and hands are a typical sign of aging ===tretinoin=== although the exact mode of action of tretinoin is unknown, current evidence suggests that tretinoin decreases cohesiveness of follicular epithelial cells. additionally, tretinoin stimulates mitotic activity and increased turnover of follicular epithelial cells. tretinoin is better known by the brand name retin-a. ===glycosaminoglycans=== glycosaminoglycans (gags) are produced by the body to maintain structural integrity in tissues and to maintain fluid balance. hyaluronic acid is a type of gag that promotes collagen synthesis, repair, and hydration. gags serve as a natural moisturizer and lubricant between epidermal cells to inhibit the production of matrix metalloproteinases (mmps). topical glycosaminoglycans supplements can help to provide temporary restoration of enzyme balance to slow or prevent matrix breakdown and consequent onset of wrinkle formation. ===dermal fillers=== dermal fillers are injectable products frequently used to correct wrinkles, and other depressions in the skin. they are often a kind of soft tissue designed to enable injection into the skin for purposes of improving the appearance. the most common products are based on hyaluronic acid and calcium hydroxylapatite. ===botulinum toxin=== botulinum toxin is a neurotoxin protein produced by the bacterium clostridium botulinum. botox (abotulinumtoxina) is a specific form of botuli
Ageing External_signs_of_aging Facial_features