Creative Touch Permanent Makeup and Aesthetics

Coenzyme Q10 occupies a position in skin biology that few other molecules share: it is simultaneously a metabolic infrastructure component and an antioxidant defence molecule, performing both functions within the same cellular location – the inner mitochondrial membrane – and with both functions declining in tandem as skin ages. Its age-related decline in the epidermis has a measurable consequence that is rarely framed plainly in consumer content: ageing skin does not just produce less energy – it shifts from predominantly aerobic (mitochondrial, efficient) to predominantly anaerobic (glycolytic, inefficient) energy generation, a metabolic state that increases advanced glycation end product formation and accelerates multiple structural ageing mechanisms simultaneously. Topical CoQ10 is one of the more thoroughly evidenced cosmeceutical actives: it demonstrably penetrates to the viable epidermis, is metabolically converted within the tissue confirming biological activity, and has clinical trial data for wrinkle depth reduction and fibroblast collagen and elastin synthesis stimulation. The most clinically important finding for anyone choosing between oral and topical CoQ10 for skin is clear: oral supplementation does not enhance CoQ10 in skin surface lipids, making topical delivery the specifically relevant route for skin-directed effect.

The Ubiquinone / Ubiquinol Redox Cycle

CoQ10 exists in two interconvertible forms determined by its oxidation state. Ubiquinone is the oxidised form – the electron acceptor, receiving electrons from the upstream respiratory chain complexes. Ubiquinol is the reduced form – produced when ubiquinone accepts electrons and is reduced, and the form that exerts the primary direct antioxidant activity outside the mitochondria. ^[1] The two forms cycle continuously: ubiquinone accepts electrons and becomes ubiquinol in the electron transport chain; ubiquinol donates electrons to free radicals and is oxidised back to ubiquinone. This redox cycling is the physical mechanism through which CoQ10 performs both its bioenergetic and antioxidant functions with the same molecule.

In human epidermis, approximately 46% of total CoQ10 is present as ubiquinol – considerably less than in plasma (where ~96% is ubiquinol) – reflecting the higher oxidative burden in UV-exposed skin tissue compared to circulating blood. With advancing age, total CoQ10 content in the epidermis declines; unlike plasma, where an age-dependent shift toward the oxidised ubiquinone form is observed alongside total decline, the epidermal decline involves both forms proportionally. ^[1]

The Electron Transport Chain Role

CoQ10 functions as the mobile electron carrier between the three principal enzyme complexes of the mitochondrial inner membrane: accepting electrons from Complex I ( NADH dehydrogenase) and Complex II (succinate dehydrogenase), and donating them to Complex III (cytochrome bc₁ complex). ^[2] This electron shuttling generates the proton gradient across the inner mitochondrial membrane that drives ATP synthase – the enzyme that produces ATP from ADP and inorganic phosphate. CoQ10 is not a catalyst in this process; it is a physical carrier, and its concentration in the inner membrane directly influences the rate at which electron transfer – and therefore ATP production – can proceed. Even small reductions in CoQ10 concentration produce disproportionately large reductions in mitochondrial respiratory rate because of the saturation kinetics of the CoQ10-dependent complexes.

In ageing skin, the decline in mitochondrial CoQ10 produces a measurable and clinically significant consequence: keratinocytes shift their primary energy generation pathway from mitochondrial aerobic respiration to non-mitochondrial anaerobic glycolysis in an attempt to compensate for reduced mitochondrial output. ^[2] This anaerobic shift is not metabolically neutral – glycolysis is substantially less efficient than oxidative phosphorylation (producing ~2 ATP per glucose vs. ~30–32 via the full mitochondrial pathway), and it preferentially generates pyruvate that is converted to lactate rather than entering the citric acid cycle. The Prahl et al. 2008 study characterised this state directly – measuring keratinocyte energy metabolism in biopsied skin samples from donors across age groups and coining the phrase “ageing skin is functionally anaerobic” to describe the finding. ^[4] Topical CoQ10 application reversed this shift, rapidly restoring aerobic mitochondrial energy generation in keratinocytes – with the oxygen consumption rate (OCR, the direct measure of mitochondrial respiration) increasing significantly from 2.79 to 3.84 fmol/min/cell in treated keratinocytes exposed to concentrations equivalent to those measured in the epidermis after two weeks of topical application. ^[1]

Clinical Pearl The anaerobic shift matters beyond energy efficiency. Anaerobic glycolysis generates pyruvate and its derivatives that react with proteins to form advanced glycation end products (AGEs) – the same cross-linking compounds addressed in the Glycation entity. Preserving mitochondrial respiration through CoQ10 replenishment reduces the intracellular substrate driving AGE formation, connecting CoQ10 to the glycation ageing pathway through an indirect but mechanistically direct route. ^[2]

The Antioxidant Role

CoQ10 is notable among endogenous antioxidants for two reasons: it is the only endogenously synthesised lipid-soluble antioxidant that operates within intracellular membranes – specifically the mitochondrial inner membrane, where lipid peroxidation chain reactions directly impair respiratory function – and it is the only antioxidant that serves a simultaneous structural role in ATP synthesis. Vitamin E and vitamin C are diet-derived; squalene, whilst also synthesised endogenously, operates primarily at the skin surface in sebum and is itself susceptible to UV-induced peroxidation.

Ubiquinol’s antioxidant mechanism in the membrane involves direct radical scavenging: it donates a hydrogen atom to lipid peroxy radicals, interrupting the chain propagation of lipid peroxidation before membrane phospholipids are oxidised. It also regenerates oxidised vitamin E (tocopheroxyl radical) back to active alpha-tocopherol – making it an indirect recycler of the vitamin E that vitamin C is simultaneously regenerating from a different position in the antioxidant network. This cooperative antioxidant network – CoQ10 in lipid membranes, vitamin E at the lipid-water interface, vitamin C in the aqueous phase – is the skin’s layered defence against oxidative damage. ^[2]

The connection to MMP-mediated collagen degradation runs through the MAPK pathway. ROS generated by UV exposure and mitochondrial dysfunction activate the mitogen-activated protein kinase (MAPK) signalling cascade, which upregulates the AP-1 transcription factor complex, driving MMP-1 (collagenase), MMP-3 (stromelysin), and MMP-9 (gelatinase) expression. ^[2] By reducing the ROS load that initiates this cascade, CoQ10 suppresses MMP expression through the same upstream ROS → MAPK → AP-1 pathway that vitamin C addresses through a parallel mechanism. The combination of the two actives – CoQ10 providing lipid membrane ROS scavenging and mitochondrial support, vitamin C providing aqueous-phase ascorbyl radical reduction and direct MMP-1 suppression – covers the ROS-to-MMP pathway more completely than either alone.

Age-Related Decline and UV Depletion

CoQ10 levels in the epidermis decline measurably across the age range of 20 to 66 years – the range studied in the Knott et al. 2015 controlled RCT (n=73). Aged epidermis showed significantly lower total quinone content (8.04 ± 0.26 ng/µg cholesterol) compared to young epidermis (9.45 ± 0.37 ng/µg cholesterol). ^[1] This decline is compounded by UV irradiation – both acute UV exposure and cumulative photoageing deplete skin CoQ10, creating an additive deficit in sun-exposed skin that exceeds chronological ageing alone.

The self-reinforcing nature of the CoQ10 decline cycle matters: reduced CoQ10 → reduced mitochondrial function → increased ROS from impaired electron transport → ROS damage further depletes CoQ10 and damages mitochondrial DNA → further mitochondrial dysfunction. This is not a linear decline but a compounding one, where the initial CoQ10 reduction accelerates the loss of the capacity to maintain CoQ10 levels.

The Statin Connection: A Shared Biosynthetic Pathway

CoQ10 is synthesised via the mevalonate pathway – the same metabolic route that produces cholesterol. The rate-limiting enzyme of the mevalonate pathway is HMG- CoA reductase, the target of statin medications. ^[3] Because statins inhibit HMG-CoA reductase to reduce cholesterol synthesis, they simultaneously reduce CoQ10 biosynthesis – an unavoidable consequence of targeting the shared upstream pathway.

The Marcheggiani et al. 2019 study modelled this directly in human dermal fibroblasts using statin concentrations across a clinically relevant range. At moderate concentrations, CoQ10 depletion produced a mitohormetic response – a compensatory adaptive increase in mitochondrial efficiency. At higher concentrations, this compensation failed, and fibroblasts entered a senescent phenotype characterised by increased SA-β-galactosidase positivity, elevated p21 (a cell cycle arrest marker), and reduced collagen and elastin expression at both gene and protein levels. ^[3] CoQ10 replenishment – particularly using ubiquinol rather than ubiquinone – reversed these senescence markers, with ubiquinol demonstrating superior subcellular mitochondrial penetration and biological activity at equivalent dose.

Ubiquinone vs. Ubiquinol: The Formulation Distinction

In topical formulations, CoQ10 is predominantly labelled as ubiquinone – the oxidised form – because it is chemically more stable and easier to incorporate into cosmetic matrices than ubiquinol. Both reach the viable epidermis following topical application, and importantly, topically applied ubiquinone is partially converted to ubiquinol within the epidermis – the Knott et al. RCT confirmed simultaneous elevation of both ubiquinone and ubiquinol in deeper epidermal layers after treatment, with the ubiquinol increase confirming active metabolic processing rather than passive accumulation. ^[1]

However, where the distinction matters most is for oral supplementation. Ubiquinol has superior gastrointestinal absorption compared to ubiquinone – owing to more efficient micellarisation during digestion and greater GSH-dependent uptake in intestinal cells – making ubiquinol the preferred oral form for systemic CoQ10 replenishment in the context of statin-associated depletion or general supplementation. For topical application specifically, the intracellular enzymatic conversion of ubiquinone to ubiquinol observed in the Knott et al. study confirms that the distinction is less critical when applying directly to skin – but products specifying ubiquinol still deliver the active antioxidant form without requiring the intracellular reduction step.