Skin Aging and Wrinkles: Causes

Close-Up Of Woman's Eye

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Skin aging and wrinkles are an inevitable part of life, caused by sun damage, smoking, genetics, environmental factors, and the normal aging process. Some of these factors can be controlled or countered through lifestyle choices, products, or procedures. Others are beyond your control.

Common Causes


As you age, your skin undergoes a series of processes that manifest in wrinkles, creases, lines and sagging. The dermal layer of the skin becomes thinner, and collagen production drops; Elastin wears out. The number of cells in the epidermis, which is the outermost layer of the skin, shrinks 10% every 10 years, thus reducing the skin's ability to repair itself. The amount of fat in the deeper layers of the skin also diminishes, and the skin begins to loosen and sag. And as the sebaceous glands produce less sebum, which is the light yellow, oily substance that helps keep skin moisturized, many people experience the dryness that is common in aging skin.

Additionally, aging skin is less able to retain moisture and is slower to heal, which contributes to the development of wrinkles. Rete ridges —thickened interconnecting ridges that increase the surface area of tissue that joins the dermal and epidermal layers of the skin into the "epidermal-dermal junction"—are flattened out by aging, thereby making the skin more fragile and conducive to shear wounds. This process also reduces the nutrients that flow to the epidermis, interfering with the skin's normal repair process.


Some people are genetically predisposed to developing wrinkles, which are most commonly found on the face, neck, forearms, and around the eyes. Your genetics may also determine how much collagen you lose as you age.

Genetics are also responsible for many skin-related characteristics, such as skin type and skin color, though researchers have not definitively isolated the genes that cause skin color.

Hormonal Changes

It is likely that the hormonal effects of menopause and decreased estrogen production contribute to the aging of the skin in women. While research has not, as of yet, determined which skin changes result from decreased estrogen levels and which are caused by excessive sun exposure or the normal aging process, studies in animals have found that a decline in estrogen decreases collagen levels by 2% a year and skin thickness by 1% each year.

Though the process of skin aging is the same in men and women, the production of collagen—which is responsible for younger-looking skin—tends to continue later in men. When testosterone production slows in the 30s and 40s, men do experience dryness and wrinkling. On the other hand, ultraviolet (UV) exposure, which is a primary aging factor, is more prevalent in men, who tend not to use sunblock and protection against the sun.

Free Radicals

Free radicals are unstable oxygen molecules that have only one electron—as opposed to the normal pair—and thus try to attach to other molecules in search of that second electron. They can alter the genetics of a cell and cause wrinkles and skin damage by activating the metalloproteinases that break down collagen. The smallest amounts of UV radiation, smoking, or exposure to air pollution can worsen this damage.

Lifestyle Risk Factors

Sun Exposure

Sun damage develops over many years of UV exposure, but is a primary cause of wrinkling, sagging, thinning skin and age spots. Exposure to the sun's UVA and UVB rays accounts for 90% of premature skin aging. The severity of skin damage by the sun is also determined by an individual's total lifetime exposure to UV radiation in addition to their specific skin (pigment) type. Most photoaging effects, including wrinkles and dark spots, occur by age 20.

Exposure to the sun affects the layers of the skin in different ways. The epidermis becomes thinner, and skin lesions—including actinic keratosesbasal cell carcinoma, and squamous cell carcinoma—may begin to form. In the dermis, sun exposure damages collagen fibers faster than normal, and elastin fibers also begin to accumulate at abnormal levels. This accumulation causes enzymes called metalloproteinases to be produced in large quantities. Typically, metalloproteinases repair skin by producing collagen, but sun damage causes them to malfunction and actually break down collagen. This leads to the formation of fibers called "solar scars." As the skin repeats this imperfect rebuilding process over and over again, wrinkles develop.

Related: Biggest Myths About Your Skin


Researchers have found that smoking causes a marked reduction in the production of new collagen and thus impairs healthy skin regeneration. Decreased collagen results in the development of wrinkles.

If you’re a heavy smoker, you may experience premature wrinkles and notice that your skin looks dramatically older than people who don't smoke. You may have lines that extend from your lip, which is common among heavy smokers. Researchers have documented the aging effects of smoking on skin and have even coined the phrase "smoker's face."

Muscle Use

As it turns out, that old wives tale is true: making funny faces and the constant contraction of facial muscles can cause the skin to wrinkle as it loses elasticity from aging. Frown lines between the eyebrows and crow's feet radiating from the corners of the eyes develop as the tiny muscles in those areas permanently contract. Smiling, frowning, squinting and other habitual facial expressions cause these wrinkles to become more prominent. Over time, these expressions, coupled with the effects of gravity, create facial wrinkles and lines. As skin becomes thinner with age, the muscles are no longer able to maintain flexibility.


The effects of gravity can loosen the skin and create the appearance of sagging due to the simple—and inevitable—gravitational pull. This can result in the jowls and drooping eyelids that are often present in older individuals.

A Word from Verywell

Many of the causes of wrinkles, sagging, lines and creases on your skin should be accepted as a normal part of the aging process. But you can stave off some skin damage through healthy lifestyle choices: minimize your exposure to the sun, don't smoke, eat healthy, and drink plenty of water. A robust "anti-aging" industry provides a variety of products and cosmetic procedures that may lessen wrinkles and lines, though pricey creams and serums can only do so much. Moisturizers can hydrate your skin and reduce dryness, and a number of cosmetic procedures administered by doctors may garner good results. But it's important to remember that skin aging is part of a normal process, and sometimes the best way to deal with wrinkles, sags, and lines is to ignore them.

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  1. Zhang S, Duan E. Fighting against Skin Aging: The Way from Bench to Bedside. Cell Transplant. 2018;27(5):729-738.