The normal course of aging alters the harmonious, symmetrical, and balanced facial features found in youth, not only impacting physical attractiveness but also influencing self-esteem and causing miscommunication of affect based on facial miscues. This evidence-based paper aims to provide a comprehensive overview of the latest research on the etiology and progression of facial aging by explaining the aging process from the “inside out”; that is, from the bony platform to the skin envelope. A general overview of the changes occurring within each of the main layers of the facial anatomy are presented, including remodeling of the facial skeleton, atrophy or repositioning of fat pads, changes in muscle tone and thickness, and weakening and thinning of the skin. This is followed by an in-depth analysis of specific aging regions by facial thirds (upper, middle, and lower thirds). This review may help aesthetic physicians in the interpretation of the aging process and in prioritizing and rationalizing treatment decisions to establish harmonious facial balance in younger patients or to restore balance lost with age in older patients.

Elastin is the main component of elastic fibers, which provide stretch, recoil, and elasticity to the skin. Normal levels of elastic fiber production, organization, and integration with other cutaneous extracellular matrix proteins, proteoglycans, and glycosaminoglycans are integral to maintaining healthy skin structure, function, and youthful appearance. Although elastin has very low turnover, its production decreases after individuals reach maturity and it is susceptible to damage from many factors. With advancing age and exposure to environmental insults, elastic fibers degrade. This degradation contributes to the loss of the skin’s structural integrity; combined with subcutaneous fat loss, this results in looser, sagging skin, causing undesirable changes in appearance. The most dramatic changes occur in chronically sun-exposed skin, which displays sharply altered amounts and arrangements of cutaneous elastic fibers, decreased fine elastic fibers in the superficial dermis connecting to the epidermis, and replacement of the normal collagen-rich superficial dermis with abnormal clumps of solar elastosis material. Disruption of elastic fiber networks also leads to undesirable characteristics in wound healing, and the worsening structure and appearance of scars and stretch marks. Identifying ways to replenish elastin and elastic fibers should improve the skin’s appearance, texture, resiliency, and wound-healing capabilities. However, few therapies are capable of repairing elastic fibers or substantially reorganizing the elastin/microfibril network. This review describes the clinical relevance of elastin in the context of the structure and function of healthy and aging skin, wound healing, and scars and introduces new approaches being developed to target elastin production and elastic fiber formation.

Injections with hyaluronic acid (HA) fillers for facial rejuvenation and soft-tissue augmentation are among the most popular aesthetic procedures worldwide. Many HA fillers are available with unique manufacturing processes and distinct in vitro physicochemical and rheologic properties, which result in important differences in the fillers' clinical performance. The aim of this paper is to provide an overview of the properties most widely used to characterize HA fillers and to report their rheologic and physicochemical values obtained using standardized methodology to allow scientifically based comparisons. Understanding rheologic and physicochemical properties will guide clinicians in aligning HA characteristics to the facial area being treated for optimal clinical performance.