Fact-checked by Grok 2 weeks ago

Wrinkle

A wrinkle is a fold, ridge, or crease in an otherwise smooth surface, such as or fabric. Wrinkles can arise in biological contexts, including the of humans and or surfaces, as well as in non-biological materials like textiles, where they result from mechanical stress, contraction, or environmental factors. The physics of wrinkling involves surface instabilities and , studied in various fields. Detailed discussions of wrinkles in , other organisms, and materials follow in subsequent sections.

Wrinkles in Human Skin

Types of Wrinkles

Wrinkles are creases, folds, or ridges in the skin that form due to the loss of elasticity and collagen, which are essential proteins supporting skin structure. This natural process is primarily driven by aging, though environmental factors can accelerate it. Wrinkles are broadly classified into static wrinkles and dynamic wrinkles based on their visibility and formation. Static wrinkles are permanent lines visible even at rest, resulting from long-term such as UV exposure that degrades over time. Common examples include forehead lines and deepened crow's feet that persist without facial movement. In contrast, dynamic wrinkles appear only during facial expressions due to repeated muscle contractions pulling on . These include lines between the eyebrows and smile lines around the mouth, which may evolve into static wrinkles with prolonged repetition. Further categorization considers depth and appearance, such as fine lines and deep wrinkles or furrows. Fine lines are shallow surface creases, often the earliest signs of aging or resulting from skin dehydration that temporarily reduces plumpness. They are typically less than 1 mm in width and depth and may appear around the eyes or before progressing. Deep wrinkles or furrows, however, are pronounced grooves exceeding 1 mm in depth, stemming from significant breakdown and often visible as persistent folds. These commonly occur on the or in the nasolabial folds extending from the to the corners. Additional types include atrophic wrinkles and gravitational wrinkles, which highlight underlying structural changes. Atrophic wrinkles manifest as thin, deep lines due to volume loss in the , where reduced and fat lead to skin thinning and hollowing. Gravitational wrinkles appear as sagging folds caused by the downward pull of combined with diminished skin support from elastin degradation. Wrinkles also vary by location, influencing their appearance and severity. Periorbital wrinkles form around the eyes, such as crow's feet radiating outward from the outer corners, often exacerbated by squinting. Perioral wrinkles develop around the mouth, including vertical lines above the upper lip or marionette lines downward from the corners, typically from repetitive pursing or smiling. Neck wrinkles present as horizontal creases or bands on the neck, resulting from skin laxity in this thinner, more exposed area.

Causes of Wrinkles

Wrinkles in arise from a combination of intrinsic and extrinsic factors that disrupt the skin's structural integrity, particularly the composed of and . Intrinsic aging, also known as chronological aging, is a genetically programmed that begins in the mid-20s to early 30s, leading to gradual reductions in cell turnover, collagen production, and elastin fibers. This results in thinner, less resilient skin as fibroblasts slow their synthesis of these proteins, with genetic variations influencing the rate and severity of these changes across individuals. Over time, the loses volume and elasticity, contributing to fine lines that deepen with advancing age. Extrinsic aging, which superimposes on intrinsic processes, is predominantly driven by environmental exposures, with (UV) radiation from accounting for 70-80% of visible skin aging signs through . UV rays penetrate the skin, generating (free radicals) that damage cellular components and activate matrix metalloproteinases (MMPs), enzymes that degrade and in the . This enzymatic breakdown disrupts the , leading to fragmented fibers and solar elastosis, which manifest as coarse wrinkles, leathery texture, and pigmentation irregularities. Lifestyle factors further accelerate wrinkle formation by exacerbating oxidative damage and impairing repair. introduces free radicals and toxins that promote , reducing blood flow and oxygen delivery to cells, while simultaneously upregulating MMPs to accelerate breakdown. Diets low in antioxidants, such as vitamins C and E, fail to neutralize free radicals effectively, allowing cumulative to weaken networks and hasten extrinsic aging. Hormonal fluctuations, particularly during , contribute significantly to wrinkle development by altering composition. The decline in levels reduces synthesis and increases its turnover, resulting in up to a 30% loss of within the first five years post-, leading to thinner, drier prone to creasing. Sleep-induced wrinkles form from forces applied during prolonged facial contact with surfaces like pillows. and stresses distort the superficial musculoaponeurotic (SMAS) layer and overlying , creating temporary folds that become more permanent with age as reduced dermal resilience impairs recovery from these distortions. Glycation, accelerated by high-sugar diets, leads to the formation of (AGEs) that covalently molecules, stiffening the and reducing its flexibility. This irreversible modification impairs 's ability to slide and recoil, promoting the rigidity and sagging associated with wrinkles.

Prevention of Wrinkles

Preventing wrinkles involves adopting proactive measures that address key modifiable risk factors, such as (UV) radiation exposure and lifestyle habits, to maintain skin elasticity and integrity over time. Sun protection remains the most effective strategy against , which accelerates wrinkle formation. Daily application of broad-spectrum with at least 30 blocks and UVB rays that degrade and in the . Wearing protective , such as wide-brimmed hats and long sleeves, and avoiding peak sun hours between 10 a.m. and 4 p.m. further reduces cumulative UV damage. These practices, when consistently followed from early adulthood, can significantly delay the onset of fine lines and deeper folds. A targeted skincare routine supports barrier function and counters . Moisturizers with humectants like help retain hydration, preventing the dryness that exacerbates wrinkle visibility. Topical antioxidants, including vitamins C and E, neutralize free radicals generated by environmental exposures, thereby preserving synthesis. Retinoids, such as or tretinoin, stimulate production and epidermal turnover; initiating use in one's 20s or 30s maximizes preventive benefits, though starting gradually minimizes irritation. Lifestyle modifications play a crucial role in fostering skin repair and circulation. A balanced diet rich in fruits, vegetables, and omega-3 fatty acids provides antioxidants and compounds that support dermal health and reduce glycation-related aging. Quitting restores microvascular circulation and halts the enzyme-mediated breakdown of , with visible improvements in skin texture emerging within months. Adequate , ideally 7-9 hours per night and on the back to avoid compression, allows for natural skin regeneration and minimizes sleep-induced creases. Maintaining internal and external counters environmental stressors that promote wrinkle development. Drinking sufficient water—at least 8 glasses daily—enhances and levels, particularly in low-water-intake individuals. Using humidifiers in dry indoor environments prevents , preserving the 's moisture barrier. Limiting consumption avoids and that impair elasticity and accelerate fine line formation. For postmenopausal women, hormonal management can mitigate estrogen decline's impact on structure. (HRT), under medical supervision, increases content and dermal thickness, reducing wrinkle depth compared to non-users. This approach is most beneficial when tailored to individual health profiles to balance skin benefits against potential risks.

Treatment of Wrinkles

Treatments for wrinkles in encompass a range of medical, cosmetic, and procedural interventions designed to reduce or eliminate visible lines by addressing underlying structural changes such as and skin laxity. These approaches target both dynamic wrinkles, caused by muscle movement, and static wrinkles, resulting from aging, with selection often depending on wrinkle type for optimal outcomes. Common methods include topical applications, injectables, surgical procedures, energy-based devices, and emerging therapies, each varying in invasiveness, duration of effect, and suitability for different skin concerns. Topical treatments form the foundation of non-invasive wrinkle management, primarily by promoting collagen production, enhancing cell turnover, and improving hydration. Retinoids, such as tretinoin, are among the most established options; tretinoin stimulates synthesis and epidermal renewal, reducing fine lines and improving skin texture, and has been FDA-approved for treatment since 1971 with subsequent recognition for . Complementary ingredients like peptides signal fibroblasts to boost and , while provides immediate hydration by binding water molecules, plumping the skin to minimize wrinkle appearance. These formulations are typically applied daily and show gradual improvements over 3-6 months, though they may cause initial . Injectable treatments offer targeted, temporary corrections for moderate to severe wrinkles. , commonly known as Botox, relaxes underlying muscles to smooth dynamic wrinkles like glabellar lines, with FDA approval for cosmetic use in 2002; effects typically last 3-6 months before requiring re-treatment. Dermal fillers, such as hyaluronic acid-based products like Juvederm, restore volume to static wrinkles and hollow areas by filling space and supporting skin structure, providing results that endure 6-18 months depending on the product's cross-linking and injection site. These minimally invasive procedures are performed in-office with and carry low risks of bruising or swelling. Surgical options provide more dramatic, long-lasting results for advanced wrinkles by physically repositioning tissues. A facelift involves elevating the skin, tightening underlying muscles and connective tissues, and removing excess fat to address sagging and deep folds, often yielding effects lasting 5-10 years. Chemical peels, using agents like , exfoliate the outer skin layers to resurface and stimulate remodeling, effectively reducing superficial wrinkles and uneven texture; light peels with 20-70% offer subtle improvements with minimal . Energy-based devices deliver controlled thermal energy to deeper layers, promoting stimulation through precise injury and healing. Laser resurfacing with CO2 or fractional ablates damaged while heating the to induce new formation, significantly improving wrinkle depth and firmness over 3-6 months post-treatment. Microneedling combined with radiofrequency creates micro-injuries and delivers heat to remodel dermal tissue, enhancing tightness and reducing fine to moderate wrinkles with effects visible after multiple sessions spaced 4-6 weeks apart. Emerging therapies leverage the body's regenerative potential for natural wrinkle reduction. Platelet-rich plasma (PRP) injections, derived from a patient's own blood, release growth factors like PDGF and TGF-β to accelerate production and tissue repair, improving skin elasticity and fine lines when administered in 3-4 sessions. LED light therapy, particularly red and near-infrared wavelengths, penetrates superficially to boost activity and synthesis without heat damage, making it suitable for mild wrinkles and suitable for home or clinical use with cumulative benefits over 8-12 weeks. These options are generally well-tolerated but require multiple treatments for sustained results.

Wrinkles in Other Organisms

Wrinkles in Animals

In non-human animals, wrinkles often represent evolutionary adaptations that enhance survival through , sensory functions, or , though they can also arise from genetic mutations or aging processes similar to those observed in collagen degradation. These skin features vary by , reflecting diverse physiological needs in terrestrial, aquatic, and arboreal environments. In large mammals such as elephants and rhinoceroses, thick, wrinkled serves a critical role in by increasing surface area for heat dissipation and retaining moisture for evaporative cooling. African elephants (Loxodonta africana) possess a cracked that traps water and mud, facilitating prolonged cooling in arid habitats where sweating is absent; this structure enhances heat exchange efficiency by increasing water retention for evaporative cooling, with the sculptured allowing 4-5 to 10 times greater moisture retention than flat surfaces. Similarly, white rhinoceroses (Ceratotherium simum) exhibit folded with a well-developed vascular bed beneath an approximately 1 mm thick , allowing efficient temperature regulation through moisture retention and insulation against environmental extremes. These adaptations likely evolved to mitigate overheating during prolonged activity in hot climates. The Chinese Shar-Pei dog breed exemplifies genetically induced wrinkles resulting from a duplication in the HAS2 gene, which overproduces hyaluronan and leads to excessive skin folding, particularly pronounced in puppies and persisting into adulthood on the head, neck, and limbs. While this trait defines the breed's morphology, the deep folds create moist, enclosed spaces prone to bacterial proliferation, resulting in recurrent skin infections () and , where eyelids invert and irritate the . Pathological consequences often necessitate surgical interventions, such as the Stades forced granulation procedure on the upper or Hotz-Celsus corner tacking, to correct eyelid malposition and prevent corneal ulceration. Functional wrinkles appear in various species for sensory or behavioral purposes. In , water-immersion wrinkling of —triggered by prolonged exposure—enhances grip on wet surfaces by channeling away and increasing , reducing the force needed to handle slippery objects by aligning it with dry conditions; this trait, observed across including macaques, suggests an adaptive response to in rainy environments. Facial skin movements in domestic (Felis catus) and (Canis lupus familiaris), involving subtle folds around the eyes, mouth, and whiskers, contribute to over 270 distinct expressions in and facilitate emotional signaling, such as slow blinks for affiliation or ear flattening for distress, aiding social communication and sensory perception. In avian species like wild turkeys (Meleagris gallopavo), the —a fleshy, vascular lobe beneath the —undergoes dynamic swelling and color changes (from pale to bright red) during mating displays, forming temporary folds that amplify visual signals to attract females and deter rivals by indicating health and arousal. Aging-related wrinkles in animals stem from progressive and degradation in the , paralleling human mechanisms but varying by species due to metabolic rates and lifespan. Small mammals like mice exhibit accelerated thinning and wrinkle formation, with content dropping up to 40% in aged models due to reduced synthesis and increased activity; in contrast, longer-lived species such as axolotls (Ambystoma mexicanum) show slower dermal remodeling with persistent regenerative capacity.

Wrinkles in Plants

In xerophytic plants, such as cacti in the family Cactaceae, folded or ribbed stem structures function as wrinkle-like adaptations to minimize water loss through transpiration. These ribs and tubercles allow the plant to expand or contract radially without excessively increasing surface area, thereby limiting exposure to dry air and reducing evaporative loss; for instance, in species like Echinocactus platyacanthus, the thick cortex (up to 300 mm) maintains hydration while the folded epidermis provides mechanical support during volume changes. Similarly, leaf venation patterns in many plants create natural creases and ridges that enhance structural integrity, acting as trusses to resist bending and wind damage while optimizing light capture for photosynthesis. In monocot leaves, for example, longitudinal V-folds or crosswise pleats form ridge-and-valley configurations that increase flexural stiffness without adding substantial mass. Developmental wrinkling occurs in young leaves due to differential growth rates between layers, leading to mechanical that puckers the surface and expands the effective area for light interception. This uneven expansion, driven by anisotropic stresses in the and mesophyll, helps young leaves achieve a three-dimensional form that boosts during early , as seen in various dicot and monocot species. In pathological contexts, viral infections like (CMV) induce leaf wrinkling as a stress response by disrupting function and signaling, causing distortion and reduced ; symptoms include mottled, puckered leaves that reflect cellular imbalance and impaired growth. Environmental similarly triggers temporary furrowing or rolling in leaves, such as in (Triticum aestivum), where turgor loss in bulliform cells folds the lamina to decrease exposed surface area, conserving and maintaining viability during midday . Wrinkling in aging fruits, exemplified by prunes (dried plums) and raisins (dried grapes), results from dehydration-induced collapse of walls, particularly through and reconfiguration of networks. As water is lost, calcium-crosslinked low-methoxyl aggregates irreversibly, reducing the tissue's ability to reswell and causing surface folding due to microstructural shrinkage and loss of turgor; this process alters mechanical properties, making the skin brittle while concentrating sugars. Evolutionarily, wrinkled in trees like oaks (Quercus spp.) serves protective roles against herbivores and , with thick, furrowed layers insulating the from heat and deterring browsing by creating an uneven, tannin-rich barrier. Cracks form as the expands annually, generating tension that splits the outer , a that enhances resistance in pyrophytic species by allowing rapid wound closure.

Wrinkles in Materials and Physics

Wrinkles in Fabrics and Textiles

Wrinkles in fabrics and textiles form primarily through the disruption of bonds within structures, particularly in cellulosic materials like . When exposed to and moisture, such as during washing or wear, water molecules penetrate between polymer chains in the , breaking the intermolecular bonds that maintain the fabric's smooth alignment. This allows the chains to slip and shift under mechanical stress, creating creases. Upon drying, the bonds reform in the new, folded positions, locking in the wrinkles. Natural fibers, such as and , are particularly prone to wrinkling due to their hydrophilic properties, which facilitate absorption and bond disruption. 's cellulose structure readily swells with water, promoting chain slippage, while 's protein-based offers slightly more resilience but still yields under prolonged stress. In contrast, synthetic fibers like exhibit greater resistance to wrinkling owing to their non-polar, smooth molecular chains that form fewer bonds and repel , maintaining structural integrity even after compression or drying. Several factors exacerbate wrinkle formation in textiles, including environmental conditions and handling practices. High promotes moisture retention in fibers, softening them and increasing to creasing during activities like prolonged sitting or improper in folded states. actions, such as tumbling in dryers, further induce wrinkles by combining with uneven . Fabric weave also plays a role; plain weaves, common in shirting, are more wrinkle-prone than weaves, which distribute stress more evenly due to their diagonal interlacing pattern. To mitigate wrinkling, chemical finishes have been developed since the , with dimethylol dihydroxyethyleneurea (DMDHEU) emerging as a key agent that cross-links cellulose chains, restricting their slippage and enhancing recovery from deformation. This urea-formaldehyde derivative, applied via padding and curing, forms a rigid within the fiber, improving durability to laundering. Permanent press fabrics extend this approach by incorporating treatments during , where thermosetting resins are impregnated into the material post-weaving but pre-sewing, then cured under heat to set shape retention properties. In fashion and daily use, wrinkles compromise aesthetic appeal by conveying dishevelment, prompting reliance on to restore flatness. applies (typically 100–200°C, varying by type) and to soften bonds, allowing manual realignment before they reform upon cooling, thus smoothing the fabric. This practice underscores broader cultural preferences for crisp appearances in and contexts, though recent trends occasionally embrace subtle creases for a relaxed aesthetic.

Physics of Wrinkling

Wrinkling in thin sheets arises as a instability when compressive stresses surpass the material's , resulting in the formation of periodic out-of-plane folds that relieve in-plane . This phenomenon is governed by the competition between bending energy, which favors smoother surfaces, and energy, which is minimized by allowing localized deformations under . In the seminal analysis by Cerda and Mahadevan, the wrinkling pattern emerges far from the instability threshold, where nonlinear geometric effects dominate, leading to a wavelength determined by the sheet's thickness and the applied confinement. For thin films deposited on compliant substrates, the wrinkle pattern is characterized by a critical that balances the film's resistance against the substrate's response. The governing relation is given by \lambda = 2\pi \left( \frac{B h}{Y} \right)^{1/4}, where B is the film's , Y is the of the substrate, and h is the substrate thickness; this formula arises in the elastic foundation model, where the substrate provides a restoring proportional to Y/h. Experimental validation of this scaling has been observed in systems where the substrate thickness modulates the wrinkle periodicity, confirming the theoretical prediction for moderate compressions. In natural systems, such as the pruney wrinkles on fingertips after prolonged immersion, epidermal relative to the underlying mimics this film-on-substrate instability, producing periodic folds with wavelengths on the order of millimeters. Technologically, engineered wrinkled surfaces exploit these principles for functional applications; for instance, controlled in thin films creates hierarchical topographies that enhance , such as gratings for tunable antireflection coatings, or improve in dry-contact systems, including gecko-inspired tapes where wrinkles facilitate conformal contact on rough substrates. Under sustained or increasing compression, initial delocalized wrinkles can transition to localized creases, where deformation concentrates into sharp, permanent folds to further minimize the total . This post-buckling behavior is modeled through energy minimization, accounting for the nonlinear coupling between and , with the crease forming when the compressive exceeds a determined by the sheet's and properties. The localization arises from an in the wrinkle , driven by the geometric nonlinearity that amplifies release in folded regions. Experimental studies illustrate these principles across diverse systems; for example, wrinkles form in drying coatings due to differential shrinkage between surface and bulk layers, producing hierarchical patterns as compressive stresses build during solvent evaporation. Similarly, in stretched sheets, out-of-plane ripples emerge under tensile loading, with their evolution governed by van der Waals interactions and substrate effects, leading to periodic undulations that persist even at low strains. In both cases, large deformations highlight the role of nonlinear geometry, where the out-of-plane deflection introduces higher-order terms in the strain energy, enabling stable wrinkled states far beyond linear predictions.

References

  1. [1]
    Wrinkles - Symptoms and causes - Mayo Clinic
    Dec 12, 2023 · Wrinkles are a natural part of aging. These lines and creases in the skin are most likely to form on skin that's often exposed to the sun.
  2. [2]
    Skin Care and Aging - National Institute on Aging - NIH
    Feb 11, 2025 · Age-related changes such as a loss of elastic fibers (elastin) and collagen cause the skin to look older, develop wrinkles, and be more fragile.
  3. [3]
    Skin anti-aging strategies - PMC - NIH
    Skin aging is a complex biological process influenced by a combination of endogenous or intrinsic and exogenous or extrinsic factors.<|control11|><|separator|>
  4. [4]
    Wrinkles & Fine Lines: Types, Causes & Prevention - Cleveland Clinic
    Wrinkles are lines or creases on your skin. It's a normal part of aging. Wrinkles that occur early in life could be the result of smoking or sun damage.
  5. [5]
    Wrinkles - PMC - PubMed Central - NIH
    Wrinkles less than 1 mm in width and depth are defined as fine wrinkles. Wrinkles that are 1 mm or more in width and depth are defined as coarse wrinkles. Most ...Missing: human | Show results with:human
  6. [6]
    Facial lines and wrinkles - DermNet
    Mild – Few wrinkles, requires little or no make-up for coverage · Moderate – Early wrinkling, sallow complexion, requires little makeup · Advanced – Persistent ...
  7. [7]
    Wrinkles & Volume Loss | University of Utah Health
    There are two types of wrinkles: Dynamic wrinkles occur when you smile, laugh, frown, or squint.Missing: human | Show results with:human
  8. [8]
    Fighting against Skin Aging: The Way from Bench to Bedside - PMC
    Exposure to UV radiation is the primary factor of extrinsic skin aging; it accounts for about 80% of facial aging. In contrast to the thinner epidermis in ...
  9. [9]
    Intrinsic and extrinsic factors in skin ageing: a review - Farage - 2008
    Mar 13, 2008 · Intrinsic structural changes occur as a natural consequence of ageing and are genetically determined. The rate of ageing is significantly different among ...
  10. [10]
    Effect of the sun on visible clinical signs of aging in Caucasian skin
    Sep 27, 2013 · Clinical signs of aging are essentially influenced by extrinsic factors, especially sun exposure. Indeed UV exposure seems to be responsible for 80% of visible ...Missing: source | Show results with:source
  11. [11]
    Role of Matrix Metalloproteinases in Photoaging and ... - MDPI
    UV radiation increases the expression of matrix metalloproteinases (MMPs) in human skin. MMPs are responsible for degrading the extracellular matrix (ECM) ...
  12. [12]
    Tobacco smoke causes premature skin aging - PubMed
    Tobacco smoke impairs collagen production, increases MMPs that degrade matrix proteins, and causes abnormal elastosis, leading to accelerated skin aging.
  13. [13]
    Diet and Skin Aging—From the Perspective of Food Nutrition - PMC
    Modern science has proven that an imbalance in nutrition and poor eating habits are important causes of skin aging. ... However, due to the instability, poor ...
  14. [14]
    Estrogens and aging skin - PMC - NIH
    Type I and III skin collagen is thought to decrease by as much as 30% in the first five years after menopause,, which parallels the reduction in bone mass ...
  15. [15]
    Sleep Wrinkles: Facial Aging and Facial Distortion During Sleep
    Jun 21, 2016 · Compression, shear, and stress forces result in facial distortion in side or stomach sleeping positions. In contrast, the only external forces ...
  16. [16]
    Sleep lines - PubMed
    We have confirmed Dr. Stegman's hallmark work on sleep wrinkles. They are accentuated by pillow contact and the underlying SMAS.Missing: compression shear forces layer<|control11|><|separator|>
  17. [17]
    Why Does Skin Go Wrinkly in Water? - News-Medical
    When a person stays in a water bath for a prolonged time, osmosis occurs and the water flows into the upper skin cells, which then take up the water.
  18. [18]
    Water-immersion finger-wrinkling improves grip efficiency in ...
    The results showed that wrinkly fingers reduce the grip force needed to grip a wet object, bringing that force in line with what is needed for handling a dry ...Missing: osmosis | Show results with:osmosis
  19. [19]
    Nutrition and aging skin: sugar and glycation - PubMed
    The effect of sugars on aging skin is governed by the simple act of covalently cross-linking two collagen fibers, which renders both of them incapable of easy ...
  20. [20]
    Wrinkle remedies - American Academy of Dermatology
    Use sunscreen, avoid tanning, moisturize, test products, limit irritating products, and allow time for products to work to reduce wrinkles.
  21. [21]
    Approaches in line with human physiology to prevent skin aging - PMC
    Oct 25, 2023 · These include avoiding prolonged and unprotected sun exposure, minimizing exposure to pollutants and polluted environments, managing temperature ...<|control11|><|separator|>
  22. [22]
    Skin care for aging skin: Minimizing age spots, wrinkles, and ...
    Dec 12, 2024 · Care for aging skin includes gentle cleansing, moisturizing, daily sunscreen, and adding antioxidants. Exfoliate gently, and use products with ...
  23. [23]
    The Real Story on Anti-Aging: Dermatologists' Expert Tips for ...
    Poor Nutrition: Diets lacking antioxidants, healthy fats, and essential vitamins can deprive the skin of the nutrients needed for repair and regeneration. Lack ...
  24. [24]
    Can your diet slow skin aging? New review reveals what helps and ...
    May 6, 2025 · However, extrinsic aging is driven by environmental stressors like ultraviolet radiation, pollution, smoking, poor sleep, and an unhealthy diet, ...
  25. [25]
    The Potential of Exercise on Lifestyle and Skin Function: Narrative ...
    Mar 14, 2024 · It has been found that smoking increases the risk of wrinkles, while excessive fat and sugar intake leads to skin aging. Lack of sleep and ...
  26. [26]
    Dietary water affects human skin hydration and biomechanics - PMC
    In this study, it is clear that higher water inputs in regular diet might positively impact normal skin physiology, in particular in those individuals with ...Missing: alcohol | Show results with:alcohol
  27. [27]
    What does alcohol do to your body and skin? - Women's Health
    Jan 2, 2025 · Well, when you drink alcohol, you increase chances of cell damage and increased skin ageing. 'Dehydration weakens the skin barrier, which can ...
  28. [28]
    Effect of estrogens on skin aging and the potential role of SERMs - NIH
    In post-menopausal women skin wrinkling has also been shown to be improved by topical estrogen therapy after a 24-week treatment period (Creidi et al 1994).Hormone Replacement Therapy · Selective Estrogen Receptor... · Serms And Skin Biology
  29. [29]
    Menopause and the effects of Hormone Replacement Therapy on ...
    Apr 17, 2024 · demonstrated that postmenopausal women receiving some form of HRT showed increased skin collagen levels, as opposed to a control group, with the ...Hrt, Collagen And Skin... · Hrt And Skin Elasticity · Hrt And Skin Water Content
  30. [30]
    Wrinkles - Diagnosis and treatment - Mayo Clinic
    Dec 12, 2023 · Wrinkle treatments include prescription creams, Botox, chemical peels, facial fillers, laser resurfacing, and face-lift surgery.
  31. [31]
    Chemical Peels for Skin Resurfacing - StatPearls - NCBI Bookshelf
    Oct 29, 2023 · Skin resurfacing with a chemical peel can restore a youthful appearance of the aging face, neck, and hands while addressing medical conditions ...
  32. [32]
    Perceived Age and Life Style. The Specific Contributions of Seven ...
    According to Kadunce (72), smoking is an independent risk factor for premature facial wrinkling, after controlling sun exposure, age, sex, and skin pigmentation ...
  33. [33]
    Benefits of topical hyaluronic acid for skin quality and signs of ... - NIH
    Oct 21, 2022 · The findings support that HA‐filler serum lengthened the duration of BoNTA's effect in reducing wrinkles, was well tolerated, and led to high ...
  34. [34]
    Advances and challenges in retinoid delivery systems in ...
    Aug 26, 2020 · ATRA is used clinically for treating photoaging, acne, and psoriasis. Indeed, ATRA was approved for acne vulgaris treatment in 1971, and since ...
  35. [35]
    Botulinum toxin (Botox) A for reducing the appearance of facial ... - NIH
    In 2002, it was recommended to be used as a cosmetic treatment for glabellar frown lines by the Food and Drug Administration (FDA).,, The second ...
  36. [36]
    Onset and Duration of AbobotulinumtoxinA for Aesthetic Use in the ...
    Dec 1, 2020 · CONCLUSION: This review indicates that aboBoNT-A has a median onset of efficacy of 2 to 3 days and a longer duration of action (3–6 months ...
  37. [37]
    Dermal fillers in aesthetics: an overview of adverse events and ...
    Dec 12, 2013 · HA derivatives are the most widely used biodegradable fillers in both Europe and the USA,, and generally have effects lasting 6–18 months ...
  38. [38]
    Face-lift - Mayo Clinic
    Aug 4, 2022 · In general, a face-lift involves elevating the skin and tightening the tissues and muscles. Fat in the face and neck may be sculpted ...
  39. [39]
    Glycolic acid peel therapy – a current review - PMC - NIH
    Some specimens showed an increase in collagen thickness in the dermis. Glycolic acid peels do not affect deep wrinkles or deep pigmentations.
  40. [40]
    Laser resurfacing - Mayo Clinic
    a ...
  41. [41]
    Fractional Laser Resurfacing Treats Photoaging by Promoting ...
    Both ablative and nonablative Erbium fractional laser resurfacing stimulate collagen reorganization and fibroblast activation in photoaged skin. However ...
  42. [42]
    Clinical and histologic evaluation of a fractional radiofrequency ...
    Fractional radiofrequency (RF) microneedling technologies have shown effectiveness in treating skin laxity and wrinkles. We report the first experience ...
  43. [43]
    Use of platelet rich plasma for skin rejuvenation - PubMed Central
    Apr 22, 2024 · Platelet‐rich plasma (PRP) is recognized as a safe and effective therapy for regenerative skin healing and rejuvenation, utilizing autologous blood enriched ...
  44. [44]
    Phototherapy with Light Emitting Diodes: Treating a Broad Range of ...
    Feb 1, 2018 · Phototherapy using LEDs is beneficial for a broad range of medical and aesthetic conditions encountered in the dermatology practice.
  45. [45]
    Elephants develop wrinkles through both form and function - PMC
    Elephant skin is known for some simple gross mechanical properties, such as a cracked epidermis for thermoregulation [8] in African elephants and entangled ...
  46. [46]
    Heat transfer in elephants: Thermal partitioning based on skin ...
    Aug 7, 2025 · The present study used a non-invasive technique, infrared thermography, to measure skin temperatures of each elephant.
  47. [47]
    Histological study of white rhinoceros integument - PMC - NIH
    Apr 25, 2017 · In this study, we report findings from a microscopic analysis of the white rhinoceros (Ceratotherium simum) integumentary ultrastructure.
  48. [48]
    Temperature regulation in the white rhinoceros - RRC
    The skin is well adapted for temprature regulation, having an epidermis about 1 mm thick, with a well-developed subjacent vascular bed.Missing: wrinkled | Show results with:wrinkled
  49. [49]
    Researchers Discover the Genetic Cause of Shar-Pei Fever
    Wrinkled skin in Shar-Pei dogs is caused by overproduction of hyaluronan, linked to the HAS2 gene. · A duplicated DNA segment near HAS2 increases risk for Shar- ...Missing: camouflage resistance
  50. [50]
    Shar-pei Special Needs and Cautions - Veterinary Partner - VIN
    Jan 1, 2001 · The enclosed spaces between the Shar-Pei's wrinkles form excellent incubators for Staphylococci and other bacteria. Skin fold infections may ...Missing: camouflage | Show results with:camouflage
  51. [51]
    Surgical management of bilateral, upper and lower eyelid entropion ...
    The forced granulation procedure performed on the upper eyelid only was effective for correction of entropion in the Shar Pei dogs included in this study.Missing: wrinkles | Show results with:wrinkles
  52. [52]
    Entropion in Shar-Pei - Wurtsboro Veterinary Clinic
    Feb 22, 2016 · Free from entropion.” Treatment of Entropion Surgical correction is indicated for hereditary entropion in the adult dog. Uncorrected entropion ...Missing: pathological | Show results with:pathological
  53. [53]
    Water-induced finger wrinkles improve handling of wet objects - NIH
    In this study, we show that submerged objects are handled more quickly with wrinkled fingers than with unwrinkled fingers, whereas wrinkles make no difference ...<|separator|>
  54. [54]
    Current Advances in Assessment of Dog's Emotions, Facial ...
    Nov 22, 2021 · This article will discuss the available literature on dogs' facial expressions, anatomy and neurophysiology, and their association with emotions and adverse ...
  55. [55]
    Cats Make Nearly 300 Different Facial Expressions
    Nov 3, 2023 · Cats have 26 different facial movements that combine to make 276 distinct expressions, according to a new study.
  56. [56]
    What's the Purpose of a Turkey's Wattle? - Mental Floss
    Oct 27, 2023 · According to some studies, the part atop a turkey's beak, called a snood, helps hens determine which toms to mate with. The longer the snood, ...
  57. [57]
    What's a turkey wattle for anyway?
    Nov 25, 2019 · A turkey wattle helps males attract hens, releases excess heat, and its color changes to show fear or illness.
  58. [58]
    A Comparative Study of Skin Changes in Different Species of Mice ...
    Jun 28, 2023 · In summary, KM mice have higher levels of abnormal elastic fibers, inflammation, cellular senescence, and oxidative stress than ICR mice, and ...
  59. [59]
    Molecular Mechanisms and In Vivo Mouse Models of Skin Aging ...
    Mar 25, 2011 · In this study, the dermatopontin-null mice showed that the skin collagen content was 40% lower and the initial elastic modulus was 57% lower ...
  60. [60]
    Collagen fiber and cellular dynamics of axolotl skin with aging - Shima
    Mar 24, 2025 · This study highlights how aging affects both the structural integrity of dermal collagen and cellular dynamics.
  61. [61]
    Structure–Function Relationships in Highly Modified Shoots of ...
    This review explains cactus shoot structure, discusses relationships between structure, ecology, development and evolution
  62. [62]
    Leaves Resist Bending — Biological Strategy - AskNature
    Sep 14, 2016 · Veins may provide supporting trusses (a), the whole leaf may be cambered lengthwise (b), or pleats can make a ridge-and-valley self-trussing ...
  63. [63]
    Leaf morphogenesis: The multifaceted roles of mechanics
    ### Summary of Developmental Wrinkling/Puckering in Young Leaves
  64. [64]
    Unraveling the Mechanisms of Virus-Induced Symptom ...
    The consequences of viral infection can manifest in a variety of symptoms, including leaf discoloration, stunted growth, wilting, necrosis, and deformities in ...
  65. [65]
    Wetting mechanism and morphological adaptation; leaf rolling ... - NIH
    Feb 1, 2022 · Leaf rolling is a common adaptive response to drought stress in plants. Leaf rolling is caused by a change in the water potential within the ...
  66. [66]
    Pectin self-assembly and its disruption by water: insights into plant ...
    Plant cell walls undergo multiple cycles of dehydration and rehydration during their life. Calcium crosslinked low methoxy pectin is a major constituent of ...<|separator|>
  67. [67]
    Suites of fire-adapted traits of oaks in the southeastern USA
    Sep 26, 2016 · Authors identified a strong correlation between traits that protect oaks against fire, such as thick bark and quick wound closure, and traits ...
  68. [68]
    The Chemistry of Ironing | American Scientist
    Water molecules insert themselves between the cellulose molecules, break up the hydrogen bonds, and act as a lubricant, allowing the cellulose molecules to ...
  69. [69]
    Why Do Clothes Wrinkle? - ThoughtCo
    Feb 8, 2020 · Absorbent fabrics allow water molecules to penetrate the areas between the polymer chains, permitting the formation of new hydrogen bonds.
  70. [70]
    News - Why Is Natural Fiber Fabric Easier to wrinkle?
    Apr 14, 2025 · Why is natural fiber fabric easier to wrinkle than synthetic fiber fabric? This is mainly related to the molecular structure, hydrophilicity ...
  71. [71]
    Origin and Properties of Synthetic and Natural Fibers
    Synthetic fibers wrinkle less, are less absorbent, don't shrink, and can be hard to dye. If you completed the burn test, natural fibers produce ash, while ...
  72. [72]
    Fabric Creases Explained: What's Behind the Wrinkles? - Aung Crown
    Sep 4, 2024 · If the storage environment is too humid, fabrics absorb water and become soft, increasing the possibility of creasing. If the environment is ...
  73. [73]
    Influence of Drying Conditions on the Wrinkling of Fabrics
    Dec 26, 2020 · Wrinkles are formed in fabrics because of mechanical action and the physicochemical effects of water and heat during washing and drying ...
  74. [74]
    [PDF] TRI-3013-Wrinkle-Resistant-Finishing-of-Cotton-Fabrics-and ...
    The construction of the garment itself will have a significant influence on wrinkle-resistant properties. Sewing thread with minimum shrinkage is important ...<|separator|>
  75. [75]
    Cotton Products Research - National Historic Chemical Landmark
    In the late 1950s, SRRC scientists initiated work on wrinkle resistance so that fewer wrinkles would form and those that did would fall out on hanging. In other ...
  76. [76]
    [PDF] Anti-crease finishing of cotton fabrics based on crosslinking of ...
    Wrinkle resistance property of treated fabrics was obtained by the follow- ing three reactions: (1) esterification between cotton cellulose and. AMA; (2) ...<|separator|>
  77. [77]
    Permanent press - MFA Cameo
    Aug 10, 2022 · Permanent press finishing is usually accomplished by impregnating the fiber with a thermosetting resin. Once the fabric is sewn and pressed ...
  78. [78]
    https://www.slate.com/human-interest/2012/10/why-do-we-iron-our-clothes-lets-just-wear-wrinkled-ones.html
  79. [79]
    How to Select the Right Iron Settings for Any Fabric - The Spruce
    Oct 21, 2025 · Recommended Ironing Temperatures ; Linen, 445°F · 230°C ; Cotton, 400°F · 204°C ; Triacetate, 390°F · 200°C ; Viscose/Rayon, 375°F · 190°C.
  80. [80]
    Geometry and Physics of Wrinkling | Phys. Rev. Lett.
    Feb 19, 2003 · We deduce a general theory of wrinkling, valid far from the onset of the instability, using elementary geometry and the physics of bending and stretching.
  81. [81]
    Wrinkled, rippled and crumpled graphene: an overview of formation ...
    This review outlines the different mechanisms of wrinkle, ripple and crumple formation, and the interplay between wrinkles' and ripples' attributes.
  82. [82]
    From wrinkles to creases in elastomers: the instability and ... - Journals
    Aug 24, 2011 · It is shown that wrinkling is highly unstable owing to the nonlinear interaction among the multiple modes associated with the critical compressive state.
  83. [83]
    Emergence of Wrinkles during the Curing of Coatings - PMC - NIH
    Wrinkle formation occurs when the first layer absorbs organic solvent from the second layer. We set up experiments to mimic the double-coating process, focusing ...