Scientists Finally Figured Out Why Wrinkles Get Deeper As You Age

Wrinkles are one of the most visible signs of aging, but the reason they actually form is more complicated than simply “losing collagen.”

For decades, scientists have understood many of the changes happening beneath aging skin. Collagen declines, elasticity decreases, and years of sun exposure can accelerate the process. What has been harder to explain is something surprisingly basic: why do those changes cause skin to physically fold into a wrinkle?

Researchers at Binghamton University decided to test the question directly. Using real human skin samples from people ranging from 16 to 91 years old, they stretched the tissue under controlled conditions and watched how its shape changed with age.

What they discovered was a mechanical difference hiding beneath the surface. Aging skin doesn’t just become less elastic. It actually responds differently when it’s pulled.

And that change may help explain why the lines that begin subtly when we’re younger become increasingly difficult for our skin to smooth away.

What the Researchers Actually Tested

Prior to this study, research modeling wrinkle formation had relied on computational and theoretical models, and no comprehensive experimental study had adequately explained why wrinkles form or validated earlier work. The Binghamton team – German along with graduate student Abraham Ittycheri and undergraduate student Alejandro Wiltshire – went directly to the tissue.

To explore the mechanics behind wrinkle formation, the researchers acquired full-thickness human skin samples from donors across a wide age range. They used histological mapping to determine the dominant collagen fiber orientation in each sample, then cut strips of skin parallel and perpendicular to this fiber direction and used a low-force tensometer to apply a consistent load, mimicking internal stress conditions. Samples were held under tension, allowing the tissue to relax and adopt its post-strain configuration.

Skin samples came from people ages 16 through 91, giving the team a broad range with which to compare how skin at different life stages responded to the same mechanical force. This was not a clinical trial testing an anti-aging cream or procedure. The study captured differences in the mechanical behavior and surface topography of ex-vivo human skin – tissue removed from the body and tested under controlled laboratory conditions. The results reveal, with physical data, the mechanical sequence that produces wrinkles, though they cannot tell us what a specific treatment does inside living skin.

The results confirmed the buckling pattern clearly. The research found that as skin ages, transverse contractile strain – the sideways shrinkage when skin is pulled lengthwise – increases during stretching, leading to deeper and wider wrinkles. Older skin didn’t simply stretch less efficiently in the forward direction; it contracts significantly more in the sideways direction compared to younger skin under equal loading.

There was also a volume problem. The high sideways contraction observed in aged skin was experimentally confirmed to correspond to volume loss in the tissue, verified through density measurements. Aging skin loses internal fluid under tension, which contributes to how dramatically it buckles and deepens. A further consistent pattern emerged from the data: wrinkles aligned with the dominant direction of collagen fibers and became more severe as the skin lost elasticity over time.

Why Aging Skin Behaves Differently

The dermis – the deeper structural layer beneath the skin’s surface – is built on a scaffolding of two proteins: collagen and elastin. Collagen forms the dense, rope-like framework that gives skin its mechanical strength, while elastin allows skin to recoil after being stretched. Both proteins decline with age, and the result affects skin mechanics directly.

Skin aging is characterized by wrinkling, loss of elasticity, laxity, and rough-textured appearance, accompanied by structural and functional changes in extracellular matrix components including collagens and elastin. When that framework weakens, skin loses its ability to distribute tension evenly across its surface. Instead of spreading a stretch smoothly and rebounding, aging skin concentrates the force, pulls hard sideways, and buckles at the point of least resistance – typically along the collagen fiber lines – producing a wrinkle.

Two main drivers degrade the collagen matrix: chronological aging and UV radiation. Chronological aging is the biological baseline; it happens regardless of where you live or how careful you are. UV radiation accelerates the process substantially. Fisher et al., 1997 (NEJM) found that multiple exposures to UV irradiation lead to sustained elevations of matrix metalloproteinases – enzymes that break down collagen and other structural proteins in the dermis – contributing directly to photoaging and wrinkle formation. The Skin Cancer Foundation has cited photoaging as responsible for approximately 90% of visible changes to the skin.

The Binghamton team’s findings align with this picture. Both chronological aging and sun exposure accelerate the mechanical effect, increasing wrinkle formation as the skin’s inherent tension and elasticity degrade over time. A 91-year-old’s skin and heavily sun-damaged skin from someone much younger can share similar mechanical patterns, because both have lost the structural integrity that keeps sideways contraction in check.

The Study’s Limitations and What They Mean for You

The study included a small sample size and an uneven gender distribution across age groups, and it focused only on sun-protected skin areas, which may limit how directly the findings apply to facial wrinkles. While testing conditions mimicked natural forces more closely than previous studies, they still did not fully replicate complex living skin behavior. These constraints mean this research is a foundation, not a final answer. The next step is studying how these mechanical patterns play out in skin that actually wrinkles first: the face, particularly around the eyes and forehead, where the forces of expression are constant and UV exposure is highest.

German has pointed to the prevention angle. Understanding the physical mechanism of wrinkling, he suggested, opens the door to better understanding how to slow it. No sunscreen, moisturizer, or skincare routine will stop the mechanical forces that act on your skin every time you move. But some of those forces – specifically the UV-driven enzyme activity that degrades collagen and amplifies the sideways buckle – can be meaningfully reduced.

What to Do With This Information

Wrinkles aren’t caused by one single process, and this study doesn’t change what researchers already know about collagen loss, declining elasticity, genetics, or years of UV exposure. What it adds is a clearer picture of how those changes eventually become a physical wrinkle.

The experiments showed that when older skin is stretched, it contracts more strongly in the opposite direction. Eventually, that sideways contraction becomes great enough that the tissue buckles, creating deeper and wider folds.

It’s a deceptively simple explanation for something researchers have spent years trying to model.

There are still important limitations. The study examined skin outside the body, included a relatively small number of samples, and primarily tested sun-protected areas rather than the face. The researchers now want to investigate areas such as the forehead and around the eyes, where repeated facial movement and sun exposure add additional forces to the equation.

But by demonstrating the process directly in human tissue spanning 75 years of age, the researchers have provided experimental evidence for something that had previously been understood largely through theoretical and computational models.

We already knew that aging changes our skin. Now we’re getting a better look at the mechanics that turn those changes into the wrinkles we eventually see in the mirror.

Disclaimer: This information is not intended to be a substitute for professional medical advice, diagnosis, or treatment and is for information only. Always seek the advice of your physician or another qualified health provider with any questions about your medical condition and/or current medication. Do not disregard professional medical advice or delay seeking advice or treatment because of something you have read here.

AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.