Why Wrinkles Appear: Causes and Mechanisms of Skin Aging

Wrinkles don't have a single cause. Their formation is the result of a combination of natural skin aging, accumulated UV exposure, repetitive facial muscle movements, and age-related changes in deeper facial tissues. Genetics determines how quickly these processes will appear, and smoking and certain environmental factors can accelerate them. [1]

At the skin level, one of the main processes is a change in the dermal framework. With age, collagen fibers become more fragmented, their quantity and quality decline, the elastic fiber system changes, and the functional activity of fibroblasts—the cells that support the intercellular substance of the dermis—decreases. Skin resists stretching less effectively and returns to its original position less easily after deformation. [2]

However, facial wrinkles aren't always just a change in the skin itself. Nasolabial folds, lines in the lower third of the face, and some deep age grooves also become more noticeable due to restructuring of the facial bone structure, changes in the volume and position of fat pads, muscle activity, and weakening of soft tissues. This is why two people of the same age can have completely different wrinkle patterns. [3]

What happens to skin as it ages?

Young dermis contains a dense and well-organized network of collagen and elastic fibers. Collagen provides mechanical strength, the elastic system helps the tissue deform and return to its original shape, and fibroblasts constantly support and renew the surrounding intercellular substance. Wrinkles develop when this framework gradually loses its ability to withstand repeated mechanical stress. [4]

With age, it's not just the amount of collagen that changes. Existing fibers fragment, their spatial organization is disrupted, and the mechanical connection between the collagen matrix and fibroblasts becomes less effective. As a result, the fibroblasts themselves receive fewer mechanical signals necessary for normal synthesis of the intercellular matrix. A vicious cycle develops: a damaged scaffold impairs cellular function, and less active cells are less able to support the scaffold. [5]

At the same time, the cells themselves age. The skin gradually accumulates cells that have entered a state of cellular senescence and no longer perform their previous functions as effectively. They are capable of secreting substances that support chronic, low-grade inflammation and activate enzymes that break down components of the intercellular matrix. These processes are now considered one of the fundamental mechanisms of skin aging. [6]

The epidermis and dermis also become thinner and less functionally resilient; the skin retains water less effectively and recovers more slowly from damage. Therefore, over time, the same facial activity that in youth only left a temporary fold increasingly easily forms a line that persists when at rest. [7]

Why does the sun have such a strong effect on wrinkles?

Chronic exposure to ultraviolet radiation is one of the most well-documented modifiable factors in premature skin aging. The skin on exposed areas of the face, neck, and hands is simultaneously subject to natural age-related aging and additional photoaging, which is why wrinkles are typically more pronounced here. [8]

Ultraviolet radiation damages skin cells and alters the signaling systems that regulate collagen. Specifically, it increases the activity of enzymes that break down various components of the intercellular matrix and can simultaneously suppress the formation of new collagen. A modern review of photoaging mechanisms, published in 2026, describes several pathways through which ultraviolet radiation leads to damage to the collagen matrix and the development of wrinkles. [9]

In photodamaged skin, the elastic system also changes. Elastic fibers become abnormally organized, and connective tissue gradually loses its normal architecture. Externally, this manifests itself not only as wrinkles, but also as a roughening of the skin's surface, decreased elasticity, pigment changes, and flabbiness. [10]

The cumulative nature of photodamage explains why the effects of excessive sun exposure are not necessarily immediately visible. Each individual dose of UV radiation does not create a deep wrinkle in a single day, but repeated damage over years alters the tissue structure. Therefore, the American Academy of Dermatology considers photoprotection a key component in preventing premature skin aging. [11]

How facial expressions turn into permanent wrinkles

Smiling, squinting, raising the eyebrows, and frowning constantly deform the skin. As long as the tissue is sufficiently elastic, the resulting fold straightens out almost completely when the muscle relaxes. These lines are called dynamic lines because they are most noticeable during facial movement. [12]

When the same area is folded thousands of times, and the dermal framework simultaneously weakens due to age and photodamage, the skin gradually becomes less able to restore its original shape. The line initially persists for some time after movement, and then becomes visible even at rest. This is how the static component of the wrinkle is formed. [13]

This mechanism was supported not only by theoretical models. In an eight-year study of women, researchers compared facial lines during facial expressions with wrinkles at rest years later and obtained data consistent with the gradual transition of some facial lines to permanent ones. [14]

Therefore, "expression" and "age" wrinkles cannot be completely contrasted. The same line may initially be dynamic and later acquire a static component due to skin aging. Ultraviolet radiation, decreased structural support, and repeated muscle contractions work together in this case. [15]

How Different Mechanisms Form Wrinkles

Mechanism	What's happening	Typical manifestations
Age-related changes in the dermis	The functionality of the collagen and elastic framework decreases	A gradual increase in the number of permanent small and deep lines
Ultraviolet	Damage to the intercellular substance of the skin accelerates	Earlier and more pronounced wrinkles in exposed areas
Facial expressions	The skin folds repeatedly over the working muscle	Forehead lines, between eyebrows, around the eyes
Loss of tissue volume	The support of the skin from below changes	Deepening of some grooves and folds
Soft tissue laxity	The tissues are less able to withstand mechanical stress.	More pronounced folds in the lower part of the face
Dryness	The top layer of skin becomes less saturated with water	Fine lines appear more noticeable, but this is not the same as the formation of deep age wrinkles.

Sources: [16]

Why do wrinkles deepen with age?

Wrinkle depth is determined by more than just the skin's surface. Computer mechanical models show that wrinkle formation depends on the interaction of several layers—the stratum corneum, the epidermis, the epidermis-dermis interface, the dermis itself, and the subcutaneous tissue. Muscle contraction of the skin and age-related tissue loss also play a role. [17]

Think of it as a multilayered fabric resting on a gradually changing base. If the top layer remains elastic and the underlying structures support it well, the surface straightens out after bending. When the outer and deeper layers simultaneously change their mechanical properties, the fold is much easier to secure.

This is why a deep nasolabial fold is fundamentally different from a fine line of dehydration. Its formation involves the geometry of the entire midface, the condition of the bone base, fat compartments, and soft tissues. Creams can affect the skin's surface, but they cannot restore lost volume to the deep tissues. [18]

This distinction has practical implications. The term "wrinkles" is often used in everyday life to refer to both superficial skin lines and deep facial folds, although their anatomical origins may differ. This is one reason why a single correction method cannot be equally effective against all age-related changes. [19]

Why do some people develop wrinkles earlier?

There is no universal threshold for the onset of wrinkles. Genetic factors, facial structure, skin pigmentation, accumulated sun exposure, facial expressions, and lifestyle all create different combinations, even in people of the same age. [20]

A genetic component is supported by studies of signs of skin aging. Genetic variants have been found associated with specific features, including the severity of wrinkles around the eyes and other signs of aging. This does not mean there is a single "wrinkle gene": it is a complex trait determined by multiple genes and the interaction of heredity and environment. [21]

Studies of identical twins are illustrative. People with virtually identical genetic makeup can still differ in the severity of skin aging if they are exposed to different environmental factors. In a study of Japanese identical twins, smoking and poor skin protection were associated with poorer skin texture and wrinkling. [22]

Therefore, the early visibility of wrinkles does not in itself indicate "accelerated aging." A person may have active facial expressions, a more pronounced tendency to wrinkles due to a certain facial shape, or greater accumulated sun exposure. Assessing skin condition solely by the number of wrinkles is inaccurate.

Smoking actually accelerates the formation of wrinkles.

The link between smoking and premature skin aging is considered fairly well-documented. A systematic review of skin aging factors found smoking to be a significant factor associated with signs of aging, and the American Academy of Dermatology and the Mayo Clinic directly link it to the premature appearance of wrinkles. [23]

The effects of tobacco smoke go beyond just pursing your lips. Experimental data show disruption of collagen synthesis, increased activity of enzymes that destroy intercellular matrix, oxidative stress, and changes in elastic structures. This creates biological conditions for a more rapid deterioration of the mechanical properties of the dermis. [24]

Facial expressions while smoking can indeed further accentuate the lines around the lips and eyes, but they are only part of the mechanism. Therefore, the common notion that "smoker's lines" arise solely from lip movement is oversimplified. [25]

Why skin may change faster after menopause

In women, declining estrogen levels during the menopausal transition are associated with skin changes, including decreased collagen synthesis, reduced elasticity, and decreased moisture retention. Combined with ongoing age-related aging, this can contribute to increased dryness, thinning, and wrinkles. [26]

A systematic review and meta-analysis of menopausal hormone therapy studies found improvements in a number of skin parameters, including collagen content, thickness, and elasticity, although the authors emphasize the need for higher-quality studies. These findings support the role of sex hormones in skin physiology but do not mean that hormone therapy should be initiated for the purpose of wrinkle reduction. [27]

The decision to use menopausal hormone therapy is based primarily on menopausal symptoms, overall health, age, time since menopause, and individual risks. Skin appearance alone should not be a basis for self-administering hormones.

Dry skin causes wrinkles or makes them more visible

Dryness can make fine lines much more noticeable, but this is not the same as the formation of deep, structural wrinkles. When the stratum corneum contains less water, its surface becomes less smooth, and fine lines become more pronounced. After applying a moisturizer, some of these lines can visibly diminish quite quickly. [28]

This effect sometimes creates the impression that the cream has "removed wrinkles." In reality, it has increased the water content of the outer layer of the skin, temporarily improving the surface. Collagen loss, permanent expression lines, or deep changes in soft tissue remain. [29]

For the same reason, a lack of drinking water and dry skin cannot automatically be considered the main cause of age-related wrinkles. Adequate hydration is important for health, but persistent wrinkle formation is explained by much more complex structural processes.

Why do wrinkles appear around the eyes?

The area around the eyes is constantly subject to deformation when smiling, squinting, and other facial movements. Therefore, dynamic lines appear especially naturally here. With age, decreased skin elasticity leads to some of these lines beginning to persist between muscle contractions. [30]

At the same time, the eye area is constantly exposed to sunlight. If a person frequently squints in bright light, two mechanisms converge: ultraviolet radiation damages the dermal framework, and repeated contractions create a mechanical fold. Sunglasses therefore not only protect the eyes but also reduce the need to constantly squint. [31]

Fine lines in this area also vary more significantly depending on the hydration of the skin's surface. This explains why the same person can look slightly different in the morning and evening without actually developing new wrinkles within a few hours. Studies have indeed documented diurnal variations in the severity of facial lines. [32]

Why do wrinkles appear on the forehead and between the eyebrows?

The skin on the forehead folds regularly when the eyebrows are raised. The area between the eyebrows is deformed when frowning. While these lines are visible only during movement, they are primarily dynamic. Later, they may also become noticeable at rest. [33]

The depth of these lines depends on more than just how actively a person moves their eyebrows. Collagen status, photodamage, skin thickness, and age-related tissue changes determine how well the surface smooths out after movement. Therefore, the degree of wrinkles in two people with similar facial expressions can vary significantly. [34]

There's no need to constantly try to control your emotions to prevent wrinkles. Sun protection and quitting smoking remain the most important modifiable factors. [35]

Why do nasolabial folds form?

The nasolabial fold is a good example of why not every deep line should be attributed to "bad skin." With age, not only the dermis but also the geometry of the middle third of the face changes: bone structures are restructured, deep and superficial fat pads can lose volume or change position, and soft tissues gradually redistribute. [36]

As a result, the border between the cheek and the area around the mouth becomes more pronounced. The skin does contribute, as it becomes less elastic, but the fold itself reflects the condition of several anatomical layers at once. [37]

Therefore, a moisturizer can make the skin surface in this area smoother, but it cannot completely remove the deep nasolabial fold if its underlying cause is related to a change in the volume and position of the tissue.

Can rapid weight loss make wrinkles worse?

A significant reduction in subcutaneous tissue volume can alter the appearance of the face and make some folds and areas of sagging more noticeable. This is especially likely if the skin's elasticity is already reduced and the tissues are less able to adapt to the changed volume. Age-related studies of the face confirm the important role of fat compartments and soft tissue volume in shaping the appearance of the aging face. [38]

But here it's also important to distinguish between a true skin wrinkle and a contour fold caused by volume changes. After weight loss, a person may notice a deeper nasolabial fold or sunken cheeks without a sudden acceleration of collagen breakdown.

Air Pollution: Proven Cause or Conjecture

The association of air pollution with skin aging is biologically plausible, and some studies have found corresponding associations. In a systematic review of skin aging factors, air pollution was included among the factors associated with age-related phenotypes. [39]

But for wrinkles, the evidence is much weaker than for UV radiation or smoking. A 2026 systematic review and meta-analysis of long-term exposure to fine particulate matter found very few relevant studies: only one study actually had data for a clinical assessment of wrinkles. The authors assessed the overall evidence base as small, heterogeneous, and of low certainty. [40]

Therefore, the assertion that "city air causes wrinkles" sounds more certain than current data suggests. Air pollution is reasonable to consider as a possible additional factor in external aging, but it should not be placed on the same level of evidence as chronic UV exposure and smoking.

Sleep and "pillow wrinkles"

The position of the face on the pillow can indeed mechanically compress and fold the skin. So-called sleep lines have been described, the location of which may differ from classic facial wrinkles. A review of the mechanics of such lines suggests that long-term, repeated compressive and shearing forces can potentially contribute to their formation. [41]

However, the evidence is far from clear. In a study of 100 women, sleep side preference was not statistically associated with either the side of the face with more pronounced wrinkles or the side with more tissue sagging.[42]

Therefore, the advice "sleep only on your back, otherwise you'll get wrinkles" isn't considered as proven as recommendations to protect yourself from UV rays or quit smoking. While the mechanical formation of individual sleep lines is possible, its contribution to overall facial aging is less well understood.

What really influences the appearance of wrinkles the most?

If we divide the factors according to the evidence and the possibility of changing them, the picture looks something like this.

Factor	The strength of the connection with wrinkles	Is it possible to change?
Natural aging	Very high	No, but you can influence external accelerating factors
Chronic exposure to ultraviolet radiation	Very high	Yes
Repetitive facial expressions	High for the relevant zones	Partially
Smoking	High	Yes
Genetic features	High role in individual differences	No
Menopausal hormonal changes	The biological contribution is well confirmed	Partially, but hormonal therapy is not prescribed for wrinkles
Loss of volume and restructuring of deep facial tissues	Well confirmed	Limited
Air pollution	Possible link, evidence specifically for wrinkles is limited	Limited
Dry skin	It has a good effect on the visibility of fine lines.	Yes
Sleeping on your side	Possible local mechanical factor, data are contradictory	Yes, but the clinical significance is unclear

Sources: [43]

Is it possible to completely prevent wrinkles?

No. Wrinkles are part of normal aging, so they cannot be completely prevented. A realistic goal is to reduce the proportion of premature aging associated with controllable factors. [44]

The most effective measure is regular protection of the skin from ultraviolet radiation. The American Academy of Dermatology recommends a broad-spectrum sunscreen with an SPF of at least 30, as well as shade, clothing, and avoiding tanning beds. [45]

The second important modifiable factor is smoking. Quitting is beneficial not only for the skin: since tobacco smoke affects blood vessels and connective tissue and is associated with numerous diseases, the cosmetic effect is just one additional argument. [46]

Moisturizing care is also helpful, but its purpose is different. It retains water in the outer layer and can reduce the appearance of some fine lines, but it doesn't replace sun protection or fully restore age-related changes in dermal collagen. [47]

What is often misunderstood

"Wrinkles appear because a person doesn't have enough water." Persistent age-related wrinkles are formed primarily due to structural and mechanical changes in the skin and deeper tissues. Insufficient surface hydration can make fine lines more noticeable, but it doesn't explain the entire aging process. [48]

"After a certain age, collagen suddenly stops being produced." The biology of aging doesn't work like a switch. Changes occur gradually, and their rate varies significantly between people, influenced by genetics, sun exposure, smoking, and other factors. [49]

"Mimic wrinkles appear only in highly emotional people." Repeated facial expressions do indeed form lines in characteristic areas, but the persistence of these lines is also determined by the condition of the skin and its ability to straighten out. [50]

"If you never smile, you won't get wrinkles." Even without active facial expressions, natural skin aging, photoaging, and deep tissue changes continue. Limiting normal emotional facial expressions is not a primary preventative strategy; it is much more beneficial to protect your skin from the sun and not smoke. [51]

"Any deep line is simply a fold of skin." Some age-related wrinkles are associated with changes in the entire anatomical framework of the face—bones, fat, ligaments, and muscles. Therefore, cosmetic creams are physically incapable of addressing all the causes of such wrinkles. [52]

Key points from experts

Elika Hoss, a board-certified dermatologist specializing in cosmetic dermatologic surgery and director of cosmetic dermatology at the Mayo Clinic in Arizona, explains that wrinkle formation is a gradual loss of key structural components of the skin—collagen, elastin, and hyaluronic acid. As a result, the skin becomes thinner, drier, and less elastic, which creates the conditions for the appearance of lines and wrinkles. [53]

Shilpi Khetarpal, a dermatologist at the Cleveland Clinic, emphasizes the structural role of collagen in the dermis and explains that the rate of its age-related decline is significantly influenced by external factors, particularly sun exposure and smoking. This is consistent with data from systematic reviews of skin aging factors. [54]

Frequently Asked Questions

Why do the first wrinkles often appear around the eyes?

Because the skin in this area is constantly deformed when smiling and squinting, and exposed areas of the face are regularly exposed to ultraviolet rays, over time the surface becomes less able to fully straighten after muscle contraction. [55]

Can wrinkles appear in a young person?

Yes. Dynamic lines appear with facial movements at any age. How early they become visible at rest depends on skin structure, heredity, the intensity of facial expressions, sun exposure, smoking, and other factors. There is no universal age for the first permanent wrinkles to appear. [56]

Is it true that dry skin ages faster?

Dry skin may appear more wrinkled due to lower water content in the surface layer. However, dryness alone does not equate to collagen breakdown or severe aging of the dermis. [57]

Why might wrinkles look lighter in the morning?

The severity of superficial wrinkles depends on hydration, tissue swelling, and mechanical stress throughout the day. Studies have indeed found diurnal changes in wrinkle severity, so a slight difference between morning and evening does not indicate rapid aging of the skin within a few hours. [58]

Is it true that the sun ages your skin even without sunburn?

Yes. Photoaging is caused by cumulative exposure to ultraviolet radiation and does not necessarily require a noticeable burn after each sun exposure. The damage accumulates gradually. [59]

Do expression lines become permanent?

Some of them may become visible over time even at rest. This occurs when repeated mechanical folding is combined with a decrease in the elasticity and structural stability of the skin. [60]

Does smoking only create wrinkles around the mouth?

No. The characteristic movement of the lips may contribute to lines around the mouth, but tobacco smoke affects the connective tissue of the skin in general and is associated with accelerated aging of the face.[61]

Is it true that air pollution greatly increases the number of wrinkles?

It's too early to say. There is data on pollution and general skin aging, but a recent meta-analysis found that there are very few high-quality studies specifically on wrinkles, and the certainty of the evidence remains low. [62]

Does the cream help prevent wrinkles?

Moisturizer can reduce the appearance of fine lines and support the skin barrier, but it cannot stop natural aging. Sun protection and quitting smoking are far more important for preventing premature changes. [63]

Should you smile less to avoid wrinkles?

There is no need to restrict normal facial expressions. Muscle movements contribute to the formation of some lines, but natural aging, sun damage, and structural tissue changes continue regardless of smiling. [64]

Main

A wrinkle forms when the skin and supporting tissues gradually lose their ability to fully restore their shape after mechanical deformation. Age-related changes in collagen and elastic fibers form the basis of this process, ultraviolet light accelerates damage to the dermal framework, facial expressions determine the placement of many lines, and changes in the fatty and bony structure of the face accentuate some deep folds. [65]

Natural aging cannot be prevented, but the amount of additional damage can be significantly reduced. Of all the household measures, regular UV protection and quitting smoking have the most convincing evidence base. Moisturizing improves the appearance of the skin's surface, but should not replace these measures and is not a way to restore lost dermal structure. [66]