Abstract

Background: Skin aging is a complex, multifactorial process governed by both intrinsic and extrinsic mechanisms. Emerging evidence demonstrates that many of these processes are regulated at the epigenetic level—through DNA methylation, histone modification, and non-coding RNA activity—without alterations to the underlying DNA sequence. Crucially, a growing body of peer-reviewed research suggests that established aesthetic treatments, including fractional lasers, injectable biostimulators such as poly-L-lactic acid (PLLA/Sculptra), calcium hydroxylapatite (CaHA/Radiesse), polycaprolactone (PCL/Ellansé), hyaluronic acid (HA) dermal fillers and Skinboosters, microneedling, and exosome-based therapies, exert a component of their regenerative effects through epigenetic or gene-expression pathways.

Objective: To synthesise current peer-reviewed evidence regarding the epigenetic and transcriptomic mechanisms underlying the most commonly used aesthetic and laser-based treatments for skin rejuvenation.

Methods: A narrative review of peer-reviewed literature published primarily between 2015 and 2025, sourced from PubMed, PMC, and major dermatology journals, focusing on studies reporting epigenetic modifications, transcriptomic changes, and gene-expression data from clinical, in vivo, and in vitro models of aesthetic treatments.

Conclusions: Aesthetic treatments operate not merely through volumetric or ablative mechanisms but also by reprogramming gene expression networks involved in extracellular matrix (ECM) synthesis, cellular senescence, and wound repair. This epigenetic dimension represents both a mechanistic explanation for the longevity of treatment effects and a compelling rationale for precision, combination approaches in aesthetic medicine.

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1. Introduction

The science of skin aging has undergone a fundamental paradigm shift. What was once viewed principally as a structural deterioration—progressive collagen loss, elastin fragmentation, and fat atrophy—is now understood to be intimately linked to alterations in gene expression regulated at the epigenetic level.¹ Epigenetics refers to heritable and reversible modifications in gene activity that occur without changes to the underlying DNA sequence.² These modifications include DNA methylation, post-translational histone modifications, and the regulation of gene expression by non-coding RNAs (ncRNAs), including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs).³

Skin is uniquely positioned at the interface between the organism and its environment, rendering it simultaneously subject to intrinsic aging—mediated by telomere attrition, mitochondrial dysfunction, and genomic instability—and extrinsic aging driven by ultraviolet (UV) radiation, pollution, smoking, and psychosocial stress.⁴ Each of these processes leaves a measurable epigenetic signature. The development of epigenetic clocks—mathematical models derived from patterns of CpG methylation at specific genomic loci—has provided researchers with tools to estimate biological skin age independently of chronological age.⁵ Seminal work by Bienkowska and colleagues demonstrated the feasibility of skin-specific epigenetic clocks capable of predicting the visual aging of human skin, and Duan et al. established epigenetic clocks broadly as both biomarkers and practical tools for understanding aging trajectories.^6,7

Within aesthetic medicine, this mechanistic shift carries significant clinical implications. The observation that many aesthetic treatments produce effects that outlast the physical residence of the intervention in the tissue—that the biostimulatory results of PLLA persist for two or more years after degradation of the polymer microspheres, for instance—raises a compelling hypothesis: that these treatments are not merely filling or scaffolding tissue but are actively modifying gene expression in a sustained manner.⁸ If aesthetic interventions are genuinely epigenetic modulators, this transforms how clinicians should conceptualise, sequence, and combine treatments.

This review compiles the peer-reviewed evidence regarding the epigenetic and transcriptomic mechanisms of the most widely used aesthetic and laser-based treatments: fractional laser resurfacing, PLLA (Sculptra), CaHA (Radiesse), PCL (Ellansé), HA dermal fillers and Skinboosters, exosome therapies, and microneedling.

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2. Epigenetic Mechanisms in Skin Aging

2.1 DNA Methylation

DNA methylation—the addition of a methyl group to cytosine residues at CpG dinucleotides—is the most extensively characterised epigenetic modification in aging skin. Hypermethylation at the promoters of genes encoding collagen crosslinking enzymes such as lysyl oxidase-like 1 (LOXL1) has been demonstrated by Moulin et al. in aged human dermal fibroblasts, with DNA methyltransferase 3A (DNMT3A) identified as the responsible enzyme.⁹ This represents a direct epigenetic mechanism for collagen network deterioration in aging skin. Chronological aging and UV exposure have been shown to produce distinct but overlapping patterns of CpG methylation, with UV-exposed skin exhibiting accelerated epigenetic aging relative to intrinsically aged counterparts.¹⁰

2.2 Histone Modifications and Chromatin Remodelling

The histone code of senescence—alterations in histone acetylation and methylation patterns in aged cells—contributes to the silencing of proliferative and repair genes and the activation of the senescence-associated secretory phenotype (SASP).¹¹ Senescent cells accumulate within the dermis with age, secreting pro-inflammatory cytokines, matrix metalloproteinases (MMPs), and growth factors that collectively impair ECM homeostasis.¹² Histone deacetylase (HDAC) activity is a key regulator of gene expression in this context, and HDAC inhibition has been shown to accelerate wound re-epithelialization through regulation of keratinocyte migration, as demonstrated by Kida et al.¹³

2.3 Non-Coding RNAs

MicroRNAs exert post-transcriptional regulation of gene expression that profoundly affects skin biology. Age-related changes in miRNA profiles modulate the expression of collagen-regulatory genes, inflammatory mediators, and ECM-remodelling enzymes.¹⁴ Long non-coding RNAs (lncRNAs), such as MALAT1, have been shown to decline with age in tissues and to modulate TGF-β1 signalling, a central driver of collagen synthesis.¹⁵ Circular RNAs (circRNAs) represent an emerging category of epigenetic regulators, with comprehensive profiling studies revealing distinct circRNA expression changes associated with skin aging.¹⁶

2.4 The Hallmarks Framework

López-Otín et al. proposed the “Hallmarks of Aging” as an expanding conceptual framework encompassing genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication.¹⁷ Skin is particularly vulnerable to all twelve hallmarks owing to its continuous cellular turnover requirements and direct environmental exposure. The epigenetic hallmark is central—it both reflects cumulative genomic damage and drives transcriptional dysregulation that underpins the structural and functional changes of aged skin.

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3. Fractional Laser Resurfacing and Epigenetic Reprogramming

3.1 Transcriptomic Evidence

Fractional laser resurfacing—particularly ablative CO₂ and Erbium fractional systems—is arguably the best characterised aesthetic treatment from a molecular standpoint. A landmark transcriptomic study by Pinto and colleagues used Affymetrix U219 microarray profiling of skin biopsies from 14 women treated with ablative fractional laser (Fraxel), collecting samples at 1, 3, 7, 14, 21, and 28 days post-treatment.¹⁸ The study demonstrated a large overlap between genes differentially expressed after laser treatment and genes dysregulated in the 50- versus 20-year-old dermis—but crucially, the laser treatment reversed the direction of expression of many aging-associated transcripts. Most strikingly, collagen genes (COL1A1, COL3A1) were among the most highly upregulated genes at day 28 post-laser, yet these same genes showed the greatest declines in expression in aged versus young skin, confirming that ablative fractional laser treatment reverses age-associated transcriptional changes at the molecular level.¹⁸

3.2 Epigenetic Mechanisms of Laser-Induced Rejuvenation

Haykal, Cartier, and colleagues published a comprehensive analysis of the epigenetic modifications induced by medical lasers in 2025, concluding that laser-induced cellular stress initiates a cascade of epigenetic reprogramming in addition to classical wound healing.¹⁹ Laser-induced microdamage causes localised inflammation that alters DNA methylation patterns at CpG islands, effectively silencing age-associated genes and reactivating the expression of collagen synthesis, ECM remodelling, and cellular repair genes.¹⁹ The reduction in MMP activity and heat shock protein expression observed post-laser treatment was interpreted as a signature of altered cellular stress response mediated through epigenetic pathways.¹⁹

Fractionated laser resurfacing (FLR) has additionally demonstrated chemoprevention effects with epigenetic implications. In a clinical study cited by Haykal et al., FLR produced a sustained reduction in actinic keratoses and a dramatic decrease in non-melanoma skin cancers (2 lesions on the treated arm versus 24 on the untreated arm over 36 months), suggesting that the epigenetic reprogramming of keratinocytes and fibroblasts by laser treatment may modify carcinogenic transcriptional programmes.¹⁹ Pedersen et al. further demonstrated that combining ablative fractional laser with topical vismodegib produced distinctive transcriptomic changes in early-stage basal cell carcinomas in murine skin, suggesting that laser therapy can potentiate the efficacy of targeted topical treatments through epigenetic modulation of tumour-associated gene expression.²⁰

3.3 Non-Ablative Fractional Lasers

Non-ablative fractional laser systems (e.g., 1540 nm and 1550 nm Erbium devices) operate through a different mechanism—generating coagulation zones without epidermal ablation—but similarly induce fibroblast activation and neocollagenesis. In vitro studies using 1540 nm fractional laser treatment of cultured human dermal fibroblasts demonstrated increased proliferation, collagen type I and III gene expression, and ECM remodelling activity, consistent with downstream epigenetic changes driven by mechanotransduction and growth factor signalling.²¹ The activation of TGF-β, VEGF, EGF, and bFGF signalling cascades observed post-laser correlates with well-characterised epigenetic programmes of wound repair.²¹

3.4 The Concept of Laser-Induced Epigenetic Clock Reset

Haykal et al. proposed, based on cumulative evidence, that fractional laser resurfacing may reduce the biological skin age as measured by epigenetic clocks.⁴ This is a provocative and important hypothesis: not only does laser treatment clinically improve the appearance of aged skin but it may also reverse measurable epigenetic age markers in the treated tissue. If validated in prospective studies incorporating epigenetic clock measurements pre- and post-treatment, this would represent a paradigm shift in how fractional laser procedures are understood and positioned within regenerative medicine.

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4. Collagen Biostimulators: Injectable Epigenetic Modulators

4.1 Poly-L-Lactic Acid (PLLA/Sculptra)

4.1.1 Gene Expression and Signal Transduction

Poly-L-lactic acid (PLLA), commercially available as Sculptra (Galderma), has been used in aesthetic medicine for over 25 years, originally for the treatment of HIV-associated facial lipoatrophy.²² Classically, its mechanism of action was described as induction of a self-limiting foreign body reaction, whereby macrophage phagocytosis of PLLA microparticles recruits fibroblasts that subsequently synthesise new collagen type I. However, recent molecular studies have substantially revised this understanding.

Kim et al. were the first to characterise the intracellular signalling pathways through which PLLA drives collagen synthesis, demonstrating in human dermal fibroblasts (Hs68 cell line) that PLLA significantly upregulates collagen type I gene expression and procollagen synthesis within 48 hours of exposure.²³ The mechanistic drivers were identified as phosphorylation of p38 MAPK, JNK, and Akt—critical second-messenger pathways that transduce cell-surface signals into nuclear gene expression changes.²³ This is a fundamentally epigenetic mechanism: PLLA activates specific kinase cascades that, through their nuclear substrates, alter transcription factor binding and chromatin accessibility at collagen gene promoters.

Zhu and colleagues extended this work, demonstrating dose-dependent upregulation of COL1A1 and COL1A2 mRNA and protein in response to PLLA, alongside changes in elastin (ELN) gene expression, tissue inhibitors of metalloprotease (TIMP-1, TIMP-2), and MMP-1.²⁴ The net effect was an anabolic shift in ECM gene expression that favoured collagen and elastin synthesis while reducing degradative enzyme activity.

4.1.2 Broader Epigenetic Effects of PLLA

The most recent and comprehensive molecular characterisation of PLLA-SCA (Sculptra) by Avelar and colleagues, published in the Journal of Cosmetic Dermatology in 2025, identifies broader epigenetic effects beyond collagen gene activation.²⁵ Gene expression studies reveal that PLLA regulates antioxidant pathways (including metallothionein 1A, MT1A), elastin synthesis (ELN), and adipocyte-related metabolic genes (MARCO, VS1GA), indicating that PLLA’s regenerative effects extend throughout the dermis, hypodermis, and adipose tissue compartments.²⁵ A concurrent paper by the same group confirmed these findings using volumetric 3D analysis, demonstrating soft-tissue formation and skin firming persisting for at least two years post-treatment and contextualising the longevity of effect as consistent with sustained epigenetic reprogramming rather than simple mechanical augmentation.²⁶

The macrophage-fibroblast axis is central to PLLA’s epigenetic mechanism. Oh et al. demonstrated that PLLA polarises macrophages towards the M2 phenotype, which is characterised by anti-inflammatory, tissue-regenerating properties and secretion of TGF-β.²⁷ TGF-β is itself a potent epigenetic modulator, activating the TGF-β/SMAD signalling cascade that drives transcription of collagen, fibronectin, and elastin genes through histone H3 acetylation and chromatin remodelling at ECM gene promoters.

4.2 Calcium Hydroxylapatite (CaHA/Radiesse)

Calcium hydroxylapatite (CaHA, Radiesse, Merz Aesthetics) consists of synthetic CaHA microspheres (25–45 μm) suspended in a carboxymethylcellulose (CMC) gel carrier.²⁸ Upon injection, the CMC gel provides immediate volumetric correction before resorption, while the CaHA microspheres act as a scaffold activating fibroblasts through direct mechanotransduction.

Nowag and colleagues published a key in vitro and ex vivo study in 2023 demonstrating that fibroblast activation by CaHA microspheres requires direct physical contact between fibroblasts and microspheres.²⁹ Sufficient inter-microsphere spacing—allowing fibroblasts to physically contact individual CaHA particles and deform against them—was identified as the critical variable determining the magnitude of neocollagenesis. This contact activates fibroblast mechanoreceptors, triggering intracellular mechanotransduction cascades that alter gene expression for collagen type I and III synthesis.²⁹

Fan et al. demonstrated that CaHA injection results in elevated procollagen gene expression and increased activity of epidermal growth factor receptor (EGFR) signalling in murine models at four weeks, consistent with activation of growth factor-mediated transcriptional programmes.³⁰ Yutskovskaya et al., in a randomised split-face histomorphological study, demonstrated that CaHA produced significantly greater collagen I and elastin synthesis than HA-based dermal filler, with cell proliferation (measured by Ki-67 marker) being greater in the CaHA group at nine months—a timeline consistent with epigenetic rather than simple inflammatory mechanism.³⁰

A comprehensive narrative review by Aguilera and colleagues (Aesthetic Surgery Journal, 2023) contextualised CaHA as a regenerative aesthetic treatment, documenting increases in collagen, elastin, proteoglycans, fibroblast populations, and neovasculature (evidenced by anti-CD31 staining) following injection.³¹ The generation of new vasculature—reflecting activation of angiogenic gene expression programmes including VEGF—is a strong indicator of sustained epigenetic reprogramming rather than simple mechanical tissue response.

4.3 Polycaprolactone (PCL/Ellansé)

Polycaprolactone (PCL, Ellansé, Sinclair Pharma) represents the third major class of injectable biostimulatory collagen stimulator. Composed of smooth PCL microspheres (25–50 μm) in a CMC carrier gel, PCL fillers degrade slowly via bulk hydrolysis of ester bonds, with longevity ranging from one to four years depending on polymer chain length.³²

Christen and Vercesi identified mechanotransduction as the primary driver of PCL’s biostimulatory mechanism, highlighting the mechanobiology of cell-matrix and cell-biomaterial interactions as central to collagen induction.³³ PCL microspheres activate fibroblast mechanoreceptors through cell-biomaterial contact, triggering intracellular signalling via multiple pathways—likely overlapping with those identified for CaHA—that convert mechanical force into transcriptional activity at ECM gene promoters.³³

A study employing injectable PEG-PCL-PEG copolymers by Liu et al. provided gene expression profiling over 24 weeks post-injection, demonstrating significant upregulation of TGF-β (peaking at 16 weeks) and COL3 (synchronously elevated), indicative of active collagen biosynthesis and sustained tissue regeneration.³⁴ The temporal pattern of gene expression—with TGF-β elevation peaking weeks after injection and collagen gene expression rising in concert—is consistent with a sustained epigenetic programme rather than a transient inflammatory spike. IL-1β and MMP-1 showed a dynamic pattern consistent with an initial inflammatory response and subsequent resolution, supporting a model of controlled epigenetic switching from a catabolic to an anabolic tissue state.³⁴

Comparative animal studies have shown that PCL produces collagen and elastin stimulation equivalent to CaHA, with the advantage of longer duration due to slower polymer degradation kinetics.³⁵ Both materials engage the fibroblast through mechanotransduction-mediated gene activation, but differ in their degradation profiles and the duration of the epigenetic stimulus they provide.

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5. Hyaluronic Acid Dermal Fillers and Skinboosters

5.1 Beyond Volumetric Augmentation

Hyaluronic acid (HA) is the most widely used injectable dermal filler globally and has conventionally been understood as a space-filling, hydrophilic material rather than a biostimulator. However, evidence accumulated over the past decade has increasingly demonstrated that HA—particularly in its cross-linked, injectable forms—exerts biologically meaningful effects on fibroblast gene expression and ECM remodelling.

Landau and Fagien provided a pivotal conceptual reframing, demonstrating that cross-linked HA can substitute for fragmented collagen in restoring the mechanical substrate required for normal fibroblast function.³⁶ Aged dermis contains mechanically deficient, fragmented collagen that fails to maintain fibroblast tensional homeostasis; fibroblasts in this environment downregulate TGF-β type II receptor expression—a key epigenetic change that reduces collagen synthesis. HA injection restores the mechanical environment, re-engaging mechanotransduction pathways that upregulate ECM synthesis.³⁶ This mechanism—mechanobiology-driven epigenetic restoration—is conceptually analogous to that described for the particulate biostimulators, though quantitatively of lower magnitude.

5.2 Skinboosters and Gene Expression

The category of HA-based Skinboosters—low cross-linked, intradermal HA preparations designed to improve skin quality rather than restore volume—includes products such as Restylane Skinboosters, Profhilo, and Skinvive (Volite).

Polycomponent injectable Skinboosters such as NCTF135HA (Filorga) add further dimensions to gene expression modulation. An in vitro study by Jäger and colleagues demonstrated that NCTF135HA increases mRNA expression of type I collagen, MMP-1, and TIMP-1 in cultured fibroblasts over 11 days, with the balance between MMP-1 (collagen-degrading) and TIMP-1 (MMP-inhibitor) enabling dynamic ECM remodelling rather than static collagen deposition.³⁷ This coordinated gene expression pattern—simultaneously upregulating both collagen synthesis and regulated turnover—is characteristic of a tissue repair programme rather than fibrosis, consistent with epigenetic activation of wound healing transcriptional networks.³⁷

Profhilo, containing 64 mg/mL HA in a thermally stabilised non-chemically crosslinked form with a unique high/low molecular weight distribution, has been proposed to modulate fibroblast activity through HA receptor (CD44, RHAMM) signalling as well as mechanical means.³⁸ The interaction between high molecular weight HA and CD44 activates Wnt and PI3K/Akt signalling pathways known to regulate gene expression for fibroblast proliferation, collagen synthesis, and stem cell recruitment—a cascade with clear epigenetic implications.

Mechanotransduction is a unifying mechanism across Skinbooster products. Yi and colleagues articulated how the mechanical deformation of fibroblast cell walls by the needle during Skinbooster injection transmits signals to the nucleus, driving cell differentiation, growth factor production, and cytoskeletal remodelling through mechanosensitive transcription.³⁹ Langevin’s experiments demonstrating increased fibroblast activity in response to needle-induced tissue deformation support the concept that even the physical act of intradermal injection contributes to gene expression changes that underpin treatment outcomes.³⁹

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6. Exosomes as Epigenetic Delivery Vehicles

6.1 Biogenesis and Cargo

Exosomes are lipid bilayer vesicles (30–100 nm) secreted by virtually all cell types via endosomal multivesicular body formation and subsequent fusion with the plasma membrane.⁴⁰ Their cargo—miRNAs, lncRNAs, mRNAs, DNA fragments, proteins, and lipids—constitutes a highly specific intercellular communication signal that can modulate gene expression and epigenetic state in recipient cells.⁴¹ This cargo is fundamentally epigenetic: miRNAs regulate gene expression post-transcriptionally, and exosome-delivered lncRNAs can interact directly with chromatin remodelling complexes.⁴¹

6.2 Stem Cell-Derived Exosomes in Skin Aging

Exosomes derived from mesenchymal stem cells (MSCs)—from bone marrow, adipose tissue, umbilical cord, and dental pulp sources—have demonstrated significant anti-aging effects on aged and photoaged skin through multiple epigenetic mechanisms.⁴² Bone marrow MSC-derived exosomes containing miR-29b-3p have been shown to alleviate UV-induced photoaging in skin fibroblasts, with this miRNA likely acting by modulating methylation of collagen gene regulatory elements.⁴³ MSC exosomes modulate DNA methylation levels in target cells to reduce inflammation, through the transfer of miR-191, miR-222, and miR-21 that regulate cell proliferation, and Let-7a, miR-222, and miR-21 that promote angiogenesis.⁴⁴

The lncRNA H19, packaged into exosomes, has been shown to ameliorate UVB-induced photoaging by upregulating SIRT1 (a histone deacetylase with pro-longevity properties) through sponging miR-138—a classic ceRNA (competing endogenous RNA) mechanism that is quintessentially epigenetic.⁴⁵ Similarly, extracellular vesicles from human dermal fibroblasts have been shown to reduce photoaging markers through the miRNA-22-5p/GDF11 axis, again illustrating how miRNA cargo functions as an epigenetic signal.⁴⁶

6.3 Exosome Effects on Key Signalling Pathways

Skin-derived and MSC-derived exosomes modulate critical epigenetically regulated pathways including MAPK, NF-κB, and TGF-β/SMAD signalling.⁴² NF-κB pathway suppression by exosomal miRNAs reduces the SASP of senescent dermal fibroblasts, attenuating the inflammatory environment that perpetuates epigenetic aging. TGF-β/SMAD pathway activation by exosome cargo drives collagen and elastin gene transcription in recipient fibroblasts.

The combination of exosomes with microneedling or other delivery technologies amplifies their efficacy. Microneedle-mediated transdermal exosome delivery creates intradermal depots of bioactive vesicles at concentrations achievable only with physical breach of the stratum corneum, enabling delivery of epigenetic cargo directly to dermal fibroblasts and keratinocytes.⁴²

6.4 Regulatory and Clinical Considerations

Exosome-based therapies represent a frontier in aesthetic medicine, with substantial regulatory variation across jurisdictions. The distinction between exosome preparations derived from defined, cGMP-manufactured cell sources and heterogeneous “conditioned media” preparations is critical for both safety and reproducibility of epigenetic effects. Standardisation of exosome isolation, characterisation (by nanoparticle tracking analysis, western blot for tetraspanin markers, and cargo profiling), and clinical delivery protocols is an active area of investigation.

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7. Microneedling and Epigenetic Wound Repair

7.1 Mechanism of Collagen Induction

Microneedling (percutaneous collagen induction, PCI) creates controlled micro-injuries within the dermis, activating the classical wound healing cascade—haemostasis, inflammation, proliferation, and remodelling—without epidermal ablation.⁴⁷ These microinjuries trigger epigenetic reprogramming through multiple overlapping mechanisms.

7.2 Growth Factor-Mediated Gene Expression Changes

Liebl and Kloth articulated the epigenetic dimension of microneedling in 2012, describing how electrotaxis signals from the wound create electrical gradients that enhance cell motility through epigenetic DNA-mediated signalling, promoting migration of epithelial and endothelial cells and initiating gene expression of wound healing growth factors.⁴⁸ The wound healing cascade recruits platelets and neutrophils that release TGF-α, TGF-β, platelet-derived growth factor (PDGF), connective tissue growth factor (CTGF), FGF, VEGF, and EGF—each capable of driving transcription factor binding and histone modification at target gene promoters.⁴⁷

The TGF-β isoforms play a particularly important and differentiated role. TGF-β1 and β2, which promote pro-fibrotic collagen deposition, show upregulation peaking at two weeks post-microneedling but decline by four weeks. TGF-β3, which promotes the anti-fibrotic, physiological lattice pattern of collagen characteristic of normal (rather than scar) skin, remains upregulated past eight weeks.⁴⁹ This isoform-selective regulation is consistent with an epigenetic programme that progressively resolves inflammatory gene expression and transitions to a regenerative, architectural collagen programme.

7.3 Molecular Profiling of Microneedling in 3D Skin Models

Schmitt and colleagues provided the first comprehensive molecular characterisation of microneedling in standardised human 3D full-thickness skin models, employing qRT-PCR and whole-transcriptome microarray analysis.⁵⁰ Microneedling upregulated genes associated with tissue remodelling (COL3A1, COL8A1, TIMP3), epithelial proliferation, and differentiation, while the epidermis showed near-complete recovery within five days. The data demonstrated that microneedling drives gene expression changes in both epidermal keratinocytes and dermal fibroblasts, establishing a molecular basis for the dual-compartment regenerative effects of the treatment.⁵⁰

A subsequent ex vivo human skin study (Scientific Reports, 2022) confirmed that microneedling increases inflammatory cytokines and angiogenic growth factors (including TGF-β, measured by ELISA) in a time-dependent fashion, alongside stimulation of epidermal proliferation and barrier renewal.⁵¹ The temporally regulated, sequential activation of these mediators is characteristic of coordinated transcriptional programmes likely governed by epigenetic switches.

7.4 Microneedling as a Delivery Platform

An important clinical consideration is microneedling’s utility as a delivery platform for topically applied epigenetically active agents. Growth factors, exosomes, PLLA-containing solutions, and nucleic acid-based therapies that cannot penetrate the intact stratum corneum can be delivered intradermally via microchannel formation. This synergy—physical access plus biological cargo—represents one of the most promising frontiers in epigenetically targeted aesthetic medicine.

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8. Discussion

8.1 Common Epigenetic Pathways Across Aesthetic Treatments

Reviewing the evidence across all treatment modalities, several common epigenetic themes emerge. First, mechanotransduction is a central mechanism shared by fractional lasers, biostimulator injectables, Skinboosters, and microneedling: the conversion of mechanical or thermal energy into intracellular signals that alter gene expression. Second, TGF-β signalling, as the master regulator of ECM gene expression, is activated by virtually all of these treatments, driving collagen and elastin synthesis through downstream SMAD-mediated chromatin remodelling. Third, modulation of the MMP/TIMP balance—the epigenetic regulation of matrix degradation versus deposition—is a consistent finding across laser, injectable, and microneedling studies, underpinning the remodelling of aged ECM. Fourth, inflammatory polarisation—particularly the promotion of M2 macrophage phenotypes by PLLA and the resolution of inflammatory programmes by exosomes—represents a shared epigenetic strategy of attenuating SASP while activating repair programmes.

8.2 The Epigenetic Clock as an Outcome Measure

The application of validated epigenetic clocks—such as Horvath’s Clock (based on 353 CpG sites), GrimAge, and the skin-specific clock developed by Bienkowska and colleagues—to aesthetic treatment research represents a transformative opportunity.^5,6 If prospective studies incorporating skin biopsies before and after fractional laser, PLLA injection, or combined treatment protocols demonstrate measurable reductions in epigenetic skin age, this would constitute the most mechanistically compelling evidence base for aesthetic medicine yet assembled. Kabacik et al. demonstrated that epigenetic age correlates directly with all hallmarks of aging in human cells, providing conceptual validation for this approach.⁵²

8.3 Combination Strategies and Epigenetic Synergy

The emerging concept of regenerative aesthetics recognises that combining treatments targeting different epigenetic pathways may produce synergistic effects. For example, fractional laser—which resets the collagen gene expression programme through thermal micro-damage—combined with intradermal PLLA injection—which provides sustained macrophage-mediated TGF-β signalling—addresses both the transcriptional dysregulation of aging fibroblasts and the compromised cellular signalling environment of aged dermis. Adding exosome delivery via microneedling introduces further epigenetic cargo (miRNAs, lncRNAs) that can modulate senescent fibroblast phenotypes and promote stem cell recruitment. This layered approach is epigenetically rational rather than empirically cumulative.

8.4 Limitations and Future Directions

The primary limitation of the current evidence base is the scarcity of prospective, controlled human studies that directly measure epigenetic endpoints (DNA methylation, histone modifications, epigenetic clock age) before and after aesthetic treatment. Most available data come from in vitro models, animal studies, or transcriptomic analyses that infer epigenetic mechanisms from gene expression patterns without direct measurement of epigenetic marks. Standardisation of epigenetic measurement methods—particularly whole methylome sequencing versus targeted CpG arrays—and the development of non-invasive or minimally invasive sampling approaches (e.g., using tape-stripping of epidermis rather than punch biopsy) are prerequisites for large-scale clinical epigenetic studies in aesthetics.

Furthermore, the dose-response relationships between treatment parameters (laser fluence, microneedle depth, injectable concentration) and epigenetic outcomes are poorly characterised. Future research should establish minimum epigenetically effective doses and investigate how treatment intervals influence the durability of epigenetic reprogramming.

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9. Conclusions

The evidence reviewed here supports a new mechanistic paradigm for aesthetic medicine: that established treatments—from fractional lasers to collagen biostimulators, from Skinboosters to exosomes—operate, in part, by modifying the epigenetic state of dermal and epidermal cells. This does not invalidate conventional biomechanical explanations (volumisation, scaffold provision, collagen induction via inflammatory signalling) but adds a deeper layer of understanding that explains the longevity, breadth, and occasionally unexpected efficacy of these treatments.

The practical implications are substantial. Epigenetic understanding enables clinicians to select and sequence treatments based on their molecular mechanism rather than their phenomenological outcome, to identify synergistic combinations, and to anticipate the biological duration of effect. In the longer term, epigenetic biomarkers—particularly validated skin epigenetic clocks—offer the prospect of objectively measuring biological treatment response beyond clinical photography and patient-reported outcomes.

Aesthetic medicine stands at the threshold of a convergence with regenerative biology. As this convergence deepens, treatments that are today classified as “cosmetic” will increasingly be recognised as genuine interventions in the molecular biology of aging skin.

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Key Takeaways

• Skin aging is governed by epigenetic mechanisms including DNA methylation, histone modification, and non-coding RNA regulation—and these are measurable using validated epigenetic clocks.
• Fractional laser resurfacing (CO₂ and Erbium, ablative and non-ablative) reverses age-associated gene expression changes in both epidermal and dermal compartments, including upregulation of collagen genes (COL1A1, COL3A1) that are most downregulated in aged skin. Evidence suggests laser may reduce skin’s biological epigenetic age.
• PLLA (Sculptra) activates collagen type I gene expression via p38 MAPK/JNK/Akt signalling cascades, and gene expression studies reveal broader epigenetic effects including regulation of elastin, antioxidant, and adipogenic pathways—explaining results that persist long after polymer degradation.
• Calcium hydroxylapatite (Radiesse) induces neocollagenesis through direct fibroblast-microsphere mechanotransduction, upregulating procollagen gene expression, EGFR signalling, and angiogenic programmes, with effects persisting to nine months.
• Polycaprolactone (Ellansé) similarly activates TGF-β and COL3 gene expression via mechanotransduction, with peak TGF-β expression at 16 weeks post-injection in vivo and duration of effect exceeding that of CaHA due to slower polymer degradation.
• Hyaluronic acid Skinboosters (Restylane, Profhilo) restore fibroblast mechanotransduction signalling by substituting for fragmented collagen in aged dermis, upregulating TGF-β type II receptor and ECM synthesis genes; polycomponent Skinboosters (NCTF135HA) additionally upregulate COL1 mRNA and regulate MMP-1/TIMP-1 balance.
• Exosomes—particularly MSC-derived vesicles—deliver miRNA cargo (including miR-29b-3p, lncRNA H19) that modulates methylation, SIRT1 activity, and collagen gene expression in recipient skin cells, representing the most directly epigenetic aesthetic treatment modality.
• Microneedling activates a temporally regulated gene expression programme including TGF-β isoform-selective upregulation (anti-fibrotic TGF-β3 predominating after 4 weeks), COL3A1, TIMP3, FGF7, and VEGF, and serves as a delivery platform for exosomes, growth factors, and other epigenetically active agents.
• A unifying mechanistic theme across all modalities is mechanotransduction-driven epigenetic reprogramming of dermal fibroblasts, converging on TGF-β/SMAD, MAPK, and NF-κB signalling axes.
• Direct measurement of epigenetic endpoints (methylation clocks, histone marks) in prospective aesthetic treatment trials is a critical unmet research need.

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Conflict of interest: None declared. Funding: None. Ethics approval: Not applicable (narrative review).

(c) Copyright Ravi Jain 2026

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