Balancing the Redox Scale: Why Mitochondrial ROS Are Not Always the Enemy

Overview

For decades, mitochondrial reactive oxygen species (ROS) have been unjustly relegated to the status of cellular metabolic waste—cytotoxic byproducts of oxidative phosphorylation that inflict indiscriminate macromolecular damage and accelerate organismal ageing. However, contemporary redox biology has fundamentally dismantled this simplistic free-radical theory. At INNERSTANDIN, our interrogation of foundational literature indexed in databases such as PubMed reveals a paradigm shift: mitochondrial ROS are not pathological anomalies, but rather indispensable, highly regulated signaling molecules that orchestrate cellular homeostasis, metabolic adaptation, and redox mechanotransduction.

The inner mitochondrial membrane continuously generates superoxide radicals ($\text{O}2^{\bullet-}$) via electron leakage from Complexes I and III of the electron transport chain (ETC) into both the mitochondrial matrix and the intermembrane space. Rather than representing system failure, this controlled flux is an evolutionary prerequisite. Dismutation of $\text{O}2^{\bullet-}$ by manganese superoxide dismutase (SOD2) yields hydrogen peroxide ($\text{H}2\text{O}2$), a relatively stable and diffusible oxidant capable of crossing biological membranes to mediate targeted post-translational modifications. Specifically, $\text{H}2\text{O}2$ reversibly oxidises critical protein thiol groups on cysteine residues—driving structural conformations that modulate transcription factor activity, kinase cascades, and phosphatase inhibition.

Far from inducing cellular collapse, physiological bursts of mitochondrial ROS are requisite for metabolic plasticity. Landmark studies in mammalian systems demonstrate that mitohormesis—a process whereby low-level mitochondrial stress confers robust resistance to subsequent, severe stressors—relies entirely on transient ROS signaling. Under conditions of nutrient excess or energetic demand, mitochondrial oxidants stabilize hypoxia-inducible factor 1-alpha (HIF-1$\alpha$) and activate AMP-activated protein kinase (AMPK), shifting cellular metabolism toward adaptive glycolysis and autophagy. Furthermore, nuclear translocation of nuclear factor erythroid 2-related factor 2 (NRF2), the master transcriptional regulator of the antioxidant response, is fundamentally triggered by localized redox signaling. Far from being depleted, intracellular antioxidant capacity is dynamically upregulated by the very ROS species the system generates.

In the UK biomedical landscape, translational research groups across leading academic institutions are currently redefining therapeutic interventions based on this nuanced understanding. Historic clinical trials attempting to mitigate disease progression via broad-spectrum antioxidant supplementation (such as high-dose vitamins C and E) largely failed or yielded paradoxical detrimental outcomes because they indiscriminately quenched physiological ROS signals required for normal insulin sensitivity, immune defense, and myocyte adaptation to exercise. Balancing the redox scale is therefore not about achieving absolute reductionist zero-ROS states, but maintaining a homeostatic set-point. True biological resilience emerges from respecting mitochondrial oxidants as vital orchestrators of cellular intelligence, bridging metabolic output with genomic regulation.

The Biology — How It Works

At the core of cellular bioenergetics lies an indispensable biochemical paradox: the very metabolic engine required to sustain eukaryotic life—oxidative phosphorylation—is inherently leaky. Electron transport chain (ETC) Complexes I and III inevitably divert single electrons to molecular oxygen ($O2$), generating superoxide radicals ($O2^{\bullet-}$). Historically, orthodox biological dogma cast these mitochondrial reactive oxygen species (mROS) as destructive metabolic by-products, driving somatic mutagenesis, lipid peroxidation, and irreversible cellular senescence via oxidative stress. However, contemporary redox biology, heavily propelled by UK-based academic consortia and published extensively across high-impact literature in The Lancet and peer-reviewed PubMed-indexed journals, has fundamentally upended this reductionist paradigm. At INNERSTANDIN, we recognise that mROS are not biological anomalies to be eradicated, but rather sophisticated, highly calibrated secondary messengers vital for systemic physiological homeostasis.

To understand this paradigm shift, one must examine the precise mechanics of mitochondrial electron slippage. Under physiological conditions, superoxide is rapidly dismutated into hydrogen peroxide ($H2O2$) by mitochondrial manganese superoxide dismutase (SOD2). While supra-physiological concentrations of $H2O2$ certainly precipitate cellular toxicity, controlled, compartmentalised flux acts as an essential post-translational modifier. Specifically, $H2O2$ orchestrates reversible thiol-based oxidation—primarily the conversion of protein cysteine thiols ($-SH$) to sulfenic acid ($-SOH$). This precise redox signaling modulates the catalytic activity, conformation, and subcellular localization of myriad downstream target proteins. For instance, mROS-mediated oxidation of critical cysteine residues inactivates protein tyrosine phosphatases, thereby amplifying essential growth factor receptor signaling cascades and driving adaptive cellular proliferation.

Crucially, mROS serve as the master regulators of physiological metabolic plasticity, most notably through hypoxia-inducible factor (HIF) pathways. During physiological hypoxia or controlled metabolic shifts, transient spikes in mitochondrial $H2O2$ inhibit prolyl hydroxylase domain proteins (PHDs). This prevents the proteasomal degradation of HIF-$1\alpha$, facilitating its nuclear translocation and the subsequent transcription of genes dedicated to angiogenesis, erythropoiesis, and glycolytic switching. Furthermore, physiological mROS production is the indispensable trigger for mitohormesis—a cytoprotective phenomenon wherein low-level, sublethal oxidative challenge upregulates endogenous antioxidant defenses, including nuclear factor erythroid 2-related factor 2 (Nrf2) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-$1\alpha$). This adaptive signaling network stimulates mitochondrial biogenesis, enhances structural integrity, and optimizes metabolic efficiency.

Therefore, broad-spectrum pharmacological intervention via high-dose exogenous antioxidants often proves counterproductive. By indiscriminately quenching physiological mROS pools, uncalibrated antioxidant therapies blunt crucial mitohormetic signaling, impairing insulin sensitivity and blunting exercise-induced muscular adaptations. True biological optimisation demands an appreciation of redox balance rather than redox elimination. The mitochondrial reticulum thrives not in the absence of ROS, but within a tightly regulated threshold—a dynamic biological equilibrium where oxidants act as the fundamental language of metabolic communication.

Mechanisms at the Cellular Level

At the subterranean level of cellular bioenergetics, the traditional dogma that mitochondrial reactive oxygen species (mtROS) are purely cytotoxic metabolic waste products has been fundamentally overturned. Landmark investigations indexed in repositories such as PubMed and highlighted by leading UK biomedical research councils reveal that superoxide anions ($O2^{\bullet-}$) and hydrogen peroxide ($H2O_2$) generated via the electron transport chain (ETC) function as indispensable secondary messengers. Far from being random leaks of cellular exhaust, controlled mtROS generation—predominantly at Complexes I and III—acts as a master switchboard for redox signalling, post-translational protein modification, and transcriptional regulation.

To comprehend this physiological paradigm, one must examine the precise mechanics of electron slippage. During oxidative phosphorylation, a fraction of electrons prematurely reduce molecular oxygen, yielding superoxide. Under homeostatic conditions, inner-mitochondrial and matrix-localized antioxidant enzymes—specifically manganese superoxide dismutase (SOD2)—rapidly dismutate superoxide into hydrogen peroxide. This $H2O2$ is not an inert byproduct; its relative stability and membrane-permeable properties allow it to diffuse into the cytosol, where it executes targeted oxidative modifications on specific cysteine residues of regulatory proteins.

This mechanism underpins redox signalling, often conceptualised as oxidative eustress. A prime biological exemplar is the hypoxia-inducible factor (HIF) pathway. Seminal British biochemical studies demonstrate that under physiological oxygen fluctuations, transient spikes in mtROS inhibit prolyl hydroxylase domain-containing proteins (PHDs). By oxidising critical iron co-factors within PHDs, mtROS prevent the proteasomal degradation of HIF-1$\alpha$, facilitating nuclear translocation and the subsequent transcription of erythropoietic and angiogenic genes essential for cellular adaptation.

Furthermore, mtROS are the primary architects of mitochondrial hormesis—colloquially termed mitohormesis. Low-level, physiological fluxes of mtROS activate nuclear factor erythroid 2-related factor 2 (Nrf2). Under basal states, Nrf2 is sequestered in the cytoplasm by Keap1. However, mtROS-mediated oxidation of specific cysteine thiols on Keap1 induces a conformational change that liberates Nrf2. Once translocated to the nucleus, Nrf2 binds to antioxidant response elements (AREs), upregulating endogenous cytoprotective enzymes including glutathione peroxidase, heme oxygenase-1, and thioredoxin. This adaptive response permanently enhances the cell’s resilience against subsequent, more severe oxidative insults.

At INNERSTANDIN, our interrogation of contemporary physiological literature underscores that indiscriminately scavenging mitochondrial oxidants—via high-dose exogenous antioxidant supplementation—frequently abolishes these vital signalling cascades, paradoxically accelerating metabolic dysfunction. Cellular vitality relies not on the eradication of mtROS, but on maintaining a finely calibrated redox set-point. Disrupting this balance impairs physiological signalling, proving that these reactive species are not biochemical adversaries, but foundational architects of human cellular longevity.

Environmental Threats and Biological Disruptors

To fully comprehend the delicate equilibrium of the mitochondrial redox scale, one must examine the exogenous stressors and biological disruptors that hijack physiological reactive oxygen species (ROS) signalling. While basal superoxide ($\text{O}2^{\bullet-}$) and hydrogen peroxide ($\text{H}2\text{O}2$) production are indispensable for mitohormesis, retrograde signalling, and nuclear gene expression via transcription factors such as Nrf2 and HIF-1$\alpha$, modern environmental pressures chronically overwhelm intrinsic antioxidant capacity. According to landmark toxicology and mitochondrial medicine reviews published in The Lancet and peer-reviewed PubMed literature, xenobiotics, persistent organic pollutants, heavy metals, and hypercaloric Western diets act as profound mitochondrial disruptors. These agents decouple oxidative phosphorylation, hyperpolarise the inner mitochondrial membrane ($\Delta\psim$), and provoke pathological electron leakage at Complexes I and III, transforming physiological signalling molecules into drivers of catastrophic oxidative distress.

Consider the mechanism of environmental toxicants such as polychlorinated biphenyls (PCBs), heavy metals like cadmium and lead, and agrochemicals (e.g., rotenone and paraquat). Rotenone, a classical inhibitor of Complex I, halts electron transfer to ubiquinone, forcing premature single-electron reductions of molecular oxygen. This uncoupling of electron flux from ATP synthesis generates an uncontrolled surge of superoxide radicals within the matrix. Concurrently, environmental endocrine-disrupting chemicals (EDCs) compromise cardiolipin—a specialised inner mitochondrial membrane phospholipid essential for maintaining the structural integrity of cristae and the optimal assembly of the electron transport chain (ETC) supercomplexes. Oxidation of cardiolipin by pathological ROS bursts causes cytochrome c detachment, compromising cellular respiration and precipitating the intrinsic pathway of apoptosis.

At the systemic level, these environmental insults induce chronic low-grade inflammation, frequently termed 'metaflammation', which synergises with mitochondrial dysfunction. Dietary advanced glycation end-products (AGEs) and circulating excess free fatty acids saturate the $\beta$-oxidation pathways, over-reducing the coenzyme Q pool and accelerating ROS generation. This sustained oxidative shift disables redox-sensitive thiol switches on key metabolic enzymes and kinases, effectively silencing adaptive mitohormetic responses. Instead of triggering protective autophagy or antioxidant enzyme upregulation, pathological ROS accumulation drives irreversible macromolecular damage, including lipid peroxidation of polyunsaturated fatty acids, protein carbonylation, and mitochondrial DNA (mtDNA) mutagenesis due to its proximity to the ETC and lack of protective histone shields.

Herein lies the central paradox explored across INNERSTANDIN modules: attempting to eradicate mitochondrial ROS entirely via high-dose, non-specific exogenous antioxidant supplementation (such as mega-dosing with vitamins C and E) often proves counterproductive. Clinical and biochemical investigations demonstrate that blunt antioxidant interventions abrogate essential redox-signalling cascades, neutralising the physiological $\text{H}2\text{O}2$ gradients required for insulin sensitivity, vascular tone regulation, and muscular adaptation to exercise. Therefore, therapeutic and preventive strategies must pivot away from crude free-radical scavenging. True redox homeostasis relies on fortifying endogenous enzymatic defences—such as superoxide dismutase (SOD2), glutathione peroxidase (GPx), and catalase—while simultaneously mitigating environmental and dietary exposures that chronically subvert the bioenergetic machinery. Restoring this physiological balance requires targeted environmental detoxification and the support of master transcriptional regulators capable of discerning between adaptive signalling ROS and destructive, environmentally induced oxidative stress.

The Cascade: From Exposure to Disease

To truly comprehend the aetiology of chronic degenerative pathology, one must transcend the simplistic, decades-old dogma that categorises mitochondrial reactive oxygen species (ROS) as purely deleterious metabolic waste. When the delicate equilibrium of the mitochondrial redox scale is chronically dysregulated—tipped into a state of unmitigated oxidative distress—a highly stereotypic molecular cascade unfolds. This biological trajectory bridges primary bioenergetic exposure with systemic pathology, challenging how translational medicine must approach therapeutic redox modulation.

As elucidated in seminal frameworks published in The Lancet and indexed widely across PubMed, the cascade initiates not from physiological, low-level superoxide ($\text{O}_2^{\bullet-}$) generation, but from electron transport chain (ETC) uncoupling and complex I or III hyper-reduction. Under pathological conditions—such as sustained nutrient excess, ischaemia-reperfusion injury, or environmental xenobiotic exposure—electron leakage outpaces the endogenous antioxidant buffering capacity, primarily mitochondrial manganese superoxide dismutase (SOD2) and glutathione peroxidase (GPx).

This localized surge in mitochondrial ROS catalyses the direct oxidation of polyunsaturated fatty acids within the inner mitochondrial membrane, precipitating lipid peroxidation chains that generate highly reactive aldehydes such as 4-hydroxynonenal (4-HNE). Concurrently, mitochondrial DNA (mtDNA), lacking protective histones and positioned in proximate geography to the ETC, suffers severe oxidative base modifications, predominantly 8-hydroxy-2'-deoxyguanosine (8-OHdG). This accumulation of mtDNA mutations impairs the transcriptional synthesis of essential oxidative phosphorylation (OXPHOS) subunits, establishing a vicious feed-forward cycle: damaged proteins engender further electron slippage, compounding ROS emission.

At INNERSTANDIN, our biological analysis emphasises that this localized organellar malfunction does not remain sequestered. The breach of the outer mitochondrial membrane triggers the cytosolic extrusion of damage-associated molecular patterns (DAMPs), including oxidized mtDNA and cardiolipin. These moieties engage innate immune sensors, most notably the NLRP3 inflammasome, driving a sterile, systemic inflammatory response characterized by sustained elevation of circulating interleukins (IL-1$\beta$, IL-18) and tumour necrosis factor-alpha ($\text{TNF}-\alpha$).

Furthermore, chronic mitochondrial oxidative stress subverts redox-sensitive transcriptional networks. While transient ROS fluxes activate nuclear factor erythroid 2-related factor 2 (NRF2) to upregulate cytoprotective enzymes—a crucial hormetic adaptation—pathological chronicity overwhelms this adaptive window. It results in the aberrant activation of pro-apoptotic pathways via cytochrome c release and caspase activation, alongside the suppression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-$1\alpha$), thereby halting mitochondrial biogenesis.

Ultimately, this cascading pathophysiology translates clinically into multi-organ deterioration. The convergence of bioenergetic failure, chronic low-grade inflammation, and cellular senescence underpins the pathogenesis of cardiogenic decline, neurodegeneration, and insulin resistance. Recognizing that mitochondrial ROS act as both physiological signaling molecules and—when dysregulated—primers of this destructive cascade is vital. Interventions designed via advanced UK biomedical research must therefore avoid blunt antioxidant strategies that abrogate physiological redox signaling, focusing instead on restoring precise mitochondrial homeostasis and metabolic flexibility.

What the Mainstream Narrative Omits

For decades, the dominant biomedical paradigm has promoted a reductive and fundamentally flawed dogma: that mitochondrial reactive oxygen species (ROS) are inherently cytotoxic metabolic waste products driving cellular senescence, oncogenesis, and accelerated aging. This simplistic "oxidative stress theory of aging"—long championed by mainstream medical literature and commercial antioxidant peddlers—fails to account for the sophisticated, highly conserved redox signaling networks that govern human physiology. At INNERSTANDIN, our critical interrogation of recent peer-reviewed literature indexed in PubMed reveals a profound oversight in this mainstream narrative. ROS are not merely pathological agents of molecular destruction; they are indispensable physiological second messengers.

Physiologically, superoxide ($\text{O}2^{\bullet-}$), generated primarily at Complexes I and III of the electron transport chain, undergoes rapid dismutation by superoxide dismutases into hydrogen peroxide ($\text{H}2\text{O}2$). Unlike highly reactive free radicals, $\text{H}2\text{O}_2$ acts as a stable, diffusible messenger capable of crossing biological membranes to execute reversible post-translational modifications of target proteins—most notably through the thiol oxidation of critical cysteine residues. This process, termed redox signaling, modulates transcription factors such as nuclear factor erythroid 2-related factor 2 (NRF2) and hypoxia-inducible factor 1-alpha (HIF-1$\alpha$). Far from triggering cellular demise, physiological pulses of mitochondrial ROS are prerequisites for metabolic flexibility, engaging endogenous antioxidant defense systems, initiating mitochondrial biogenesis, and orchestrating precise apoptotic pathways in damaged cells.

Clinical and translational investigations conducted across British academic medical centres demonstrate the catastrophic consequences of disrupting this delicate redox homeostasis via exogenous antioxidant supplementation. High-dose, non-targeted administration of antioxidants such as vitamins C and E often neutralises beneficial ROS pools, blunting the hormetic signaling cascades required for metabolic adaptation. As demonstrated by landmark oncological studies published in The Lancet and related high-impact journals, suppressing ROS can paradoxically promote disease progression by disabling tumour-suppressor pathways and impairing the physiological cytotoxicity required for immune cell activation and pathogen clearance.

To truly innerstand cellular longevity and metabolic resilience, researchers must abandon the archaic dichotomous view of oxidation versus reduction. Mitochondria operate as dynamic redox rheostats. Therapeutics and nutritional interventions must therefore pivot away from broad-spectrum antioxidant bludgeoning and toward targeted metabolic optimisation that preserves the vital signalling language of mitochondrial ROS.

The UK Context

Within the United Kingdom, translational biogerontology and metabolic research spearheaded by institutions such as the Medical Research Council (MRC) Mitochondrial Biology Unit in Cambridge have fundamentally re-evaluated the paradigm of mitochondrial reactive oxygen species (ROS). For decades, the free radical theory of ageing—pioneered in the mid-twentieth century—cast superoxide ($O2^{\bullet-}$) and hydrogen peroxide ($H2O_2$) purely as pathological byproducts of oxidative phosphorylation, driving macromolecular damage across cellular lipids, proteins, and nuclear DNA. However, contemporary UK-led peer-reviewed investigations, frequently catalogued via PubMed-indexed consortia, demonstrate that physiological fluxes of mitochondrial ROS are indispensable signaling molecules required for cellular homeostasis, immune competence, and metabolic adaptation.

At the core of this redox signaling network is post-translational modification via reversible cysteine oxidation. Low, tightly regulated concentrations of mitochondrial ROS act as primary second messengers in pathways governing hypoxia-inducible factor (HIF) stabilization, AMP-activated protein kinase (AMPK) activation, and nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation. This Nrf2-antioxidant response element (ARE) axis, heavily scrutinized in British clinical trials concerning neurodegeneration and cardiometabolic syndromes, proves that basal ROS generation is the exact trigger required to upregulate endogenous cytoprotective enzymes, including superoxide dismutase and glutathione peroxidase.

Furthermore, epidemiological data emerging from the UK Biobank cohorts regarding metabolic dysfunction-associated steatotic liver disease (MASLD) and type 2 diabetes mellitus underscore the dangers of blunt antioxidant interventions. Clinical trials utilizing high-dose, non-specific exogenous antioxidants—such as synthetic vitamin E or uncurated polyphenol supplementation—frequently fail or accelerate pathology because they quench physiological ROS pools essential for insulin signaling and mitochondrial biogenesis. At INNERSTANDIN, our synthesis of these findings reveals that attempting to eradicate mitochondrial ROS disrupts hormetic signaling cascades, a phenomenon known in redox biology as 'antioxidant paradox'. True therapeutic strategies in British molecular medicine are therefore shifting away from broad-spectrum scavenging toward compartmentalized redox modulation, targeting specific electron transport chain complexes to preserve vital physiological signaling while mitigating pathological oxidative stress.

Protective Measures and Recovery Protocols

Thermodynamic efficiency within the human electron transport chain is intrinsically imperfect, inevitably resulting in electron leakage at Complexes I and III that generates superoxide radicals ($O_2^{\bullet-}$). Historically, biomedical dogma categorised these mitochondrial reactive oxygen species (mROS) purely as pathological stressors responsible for macromolecular damage and cellular senescence. However, contemporary redox biology—extensively documented in publications across The Lancet and peer-reviewed repositories on PubMed—reveals a vastly more nuanced reality. mROS operate as indispensable signalling molecules required for metabolic adaptation, immune competence, and epigenetic regulation. Consequently, modern recovery protocols must abandon the outdated paradigm of aggressive, indiscriminate antioxidant supplementation. Instead, interventions must focus on modulating redox flux to preserve physiological signalling while mitigating nitro-oxidative stress.

At the core of endogenous cellular defence is the Kelch-like ECH-associated protein 1 (Keap1) / Nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Under basal conditions, Keap1 sequesters Nrf2 in the cytosol, targeting it for ubiquitin-mediated proteasomal degradation. However, a controlled, physiological pulse of mROS oxidises specific critical cysteine residues on Keap1, inducing a conformational change that liberates Nrf2. Translocation of Nrf2 to the nucleus subsequently drives the transcription of cytoprotective genes containing Antioxidant Response Elements (AREs), including glutathione peroxidase (GPx), superoxide dismutase (SOD), and heme oxygenase-1 (HO-1). Artificially suppressing initial mROS cascades via high-dose pharmacological antioxidants—such as megadoses of exogenous vitamin C or E—blunts this hormetic signaling loop, leaving the cell functionally more vulnerable to subsequent oxidative insults. This phenomenon, frequently observed in endurance training adaptations, underscores why INNERSTANDIN emphasises strategic redox modulation over blunt-force free radical scavenging.

Therapeutic interventions must therefore prioritize enhancing mitochondrial biogenesis and endogenous enzymatic efficiency over stoichiometric radical quenching. Clinical investigations highlighted in UK-based metabolic research demonstrate that intermittent hypoxic conditioning and zone-2 cardiovascular training upregulate peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-$1\alpha$). This master regulator coordinates mitochondrial network expansion, concurrently increasing the expression of manganese superoxide dismutase (MnSOD) within the mitochondrial matrix. Furthermore, nutritional strategies focusing on hormetic phytochemicals—such as sulforaphane derived from cruciferous vegetables—act as indirect antioxidants by safely triggering the Nrf2 pathway without disrupting the vital physiological thresholds required for insulin sensitivity and vascular tone.

Ultimately, mastering redox biology within advanced educational frameworks like INNERSTANDIN requires a paradigm shift from mitigation to optimization. By respecting the signalling fidelity of mitochondrial ROS, clinicians and researchers can design evidence-led protocols that harness oxidative hormesis, fortifying cellular resilience from the foundational organelle upward.

Summary: Key Takeaways

Mitochondrial reactive oxygen species (mROS) have undergone a radical paradigm shift within contemporary redox biology, transitioning from the outdated view of mere metabolic waste products to indispensable, highly regulated signalling molecules. Seminal peer-reviewed literature indexed on PubMed increasingly demonstrates that physiological mROS thresholds are paramount for orchestrating optimal cellular homoeostasis, specifically through reversible cysteine thiol oxidation that modulates downstream transcription factors such as Nrf2 and HIF-1α. As highlighted by investigators across UK research institutions, attempting to blunt this intricate oxidative signalling network via indiscriminate antioxidant supplementation often disrupts essential hormetic pathways, thereby impairing mitochondrial biogenesis, physiological adaptation to exercise, and endogenous cytoprotective defences. At INNERSTANDIN, we emphasize that true metabolic resilience relies not on reductive eradication, but on precise, system-wide redox equilibrium. Future clinical interventions and therapeutic paradigms must pivot away from blunt-force scavenging and toward targeted modulatory strategies that preserve vital redox-dependent physiological signalling cascades.