6 Things That Cause Wrinkles

Normal Skin & Chronological Aging

Close up portrait pensive senior woman looking away
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Wrinkles: they're unavoidable. While much of why we get them has to do with the inevitable effects of aging, there are quite a few external factors, some of which you may have never considered until now. To fully understand how we age and what causes wrinkles, it helps to understand the anatomy of the skin.

Skin is made up of three layers:

  • Epidermis: The epidermis is the outermost layer of the skin. It acts as a barrier to the external elements. Within this layer, new cells are constantly growing and push older cells closer to the surface of the skin, where they will eventually shed. If this process ever becomes abnormal, the skin can appear scaly and flaky.
  • Dermis: The second layer of skin is the dermis. It contains the structural elements of the skin; the connective tissue. Different types of connective tissues serve different functions. For example, collagen gives skin strength and plumpness, proteins known as glycosaminoglycans give skin turgor, and elastin give skin elasticity.

    The dermal-epidermal junction lies between the dermis and the epidermis. This important structure interlocks, forming fingerlike projections called rete ridges. Cells in the epidermis get nutrients from blood vessels in the dermis. Rete ridges increase the surface area of the epidermis exposed to blood vessels and essential nutrients.
  • Subcutaneous tissue: The bottom, innermost layer of skin is the subcutaneous tissue, which is largely made up of fat cells that insulate the body and made skin appear plump and full. It also contains sebaceous glands, sweat glands and hair follicles, among other structures.

    Wrinkles and other signs of aging are caused by a number of factors. Some you can control, others you can't. Here are six causes of aging:

    1. Chronological Aging

    As a person ages, epidermal cells become thinner and less sticky, causing the skin to look noticeably thinner. The lack of stickiness also hinders the skin's barrier function, allowing moisture to be released instead of being retained in the skin.

    This causes dryness. The number of epidermal cells decreases by 10 percent per decade, and they divide more slowly as we age, making the skin less able to repair itself quickly.

    The effects of aging on the dermal layer are significant. Not only does the dermal layer thin, but less collagen is produced and elastin fibers wear out. These changes in the scaffolding of the skin cause it to wrinkle and sag. The sebaceous glands get bigger, but produce less sebum, and the number of sweat glands decreases. Both of these changes lead to dry skin.

    The rete ridges of the dermal-epidermal junction flatten out, making skin more fragile and easy to shear. This process also reduces the amount of nutrients available to the epidermis because it decreases the amount of surface area in contact with the dermis, interfering with the skin's normal repair process.

    2. Sun Damage

    Exposure to UVA and UVB rays from sunlight accounts for 90 percent of premature skin aging symptoms. Most of the photoaging effects, including wrinkles and dark spots, occur by age 20.

    The amount of damage the sun does to the skin is determined by an individual's total lifetime amount of radiation exposure, as well as their pigment protection.

    It affects the layers of the skin in different ways:

    • Epidermis: The epidermis becomes thinner and skin lesions, such as actinic keratosesbasal cell carcinomas and squamous cell carcinomas form.
    • Dermis: In the dermis, the sun damages collagen fibers faster than chronological aging and elastin accumulates at abnormal levels. The accumulation of elastin causes metalloproteinases, or enzymes, to be produced in large quantities. The metalloproteinases typically repair skin by producing collagen, but sun damage causes them to malfunction and actually break down collagen. It results in the formation of disorganized collagen fibers known as solar scars. As skin repeats this imperfect rebuilding process over and over again, wrinkles develop.

    3. Free Radicals

    Free radicals are unstable oxygen molecules that have only one electron instead of two. Because electrons are found in pairs, the molecule must scavenge other molecules for another electron. When the second molecule loses its electron to the first molecule, it has to find another electron, repeating the process.

    This process can damage cell function and alter genetic material. Free radical damage causes wrinkles by activating the metalloproteinases that break down collagen. There are several factors that kickstart this cascading process, including exposure to even the smallest amounts of UV radiation, smoking and exposure to air pollution.

    4. Hormonal Changes

    It is likely that the hormonal effects of menopause and decreased estrogen production are responsible for skin aging. However, studies of human subjects have not discovered which skin changes are specific to decreased estrogen or which skin changes are a result of sun exposure or normal chronological aging. Studies of animals have found that a lack of estrogen can cause a decrease in collagen levels of 2 percent per year, and a decrease in skin thickness of 1 percent per year.

    Speaking of changes, drastic changes in weight may also may also affect the look of your skin. You may find that the skin on your face looks healthier after weight loss, for example, or that you look younger and more vibrant.

    5. Muscle Use

    Habitual facial expressions cause the skin to wrinkle as it loses elasticity. Frown lines between the eyebrows and crows feet radiating from the corners of the eyes develop as the tiny muscles in those areas permanently contract.

    6. Gravity

    The effects of gravity make the loosening of the skin more apparent as skin sags more. This causes jowls and drooping eyelids.

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