Creative Touch Permanent Makeup and Aesthetics

Obstructive sleep apnoea is a condition in which the upper airway partially or completely collapses during sleep, causing repeated interruptions to breathing that fragment sleep architecture and trigger a cascade of oxidative stress, inflammatory signalling, and hormonal dysregulation. It is strongly associated with obesity – with prevalence exceeding 70–80% in patients assessed for bariatric surgery, and substantially elevated even in the general class III BMI population – yet it is estimated that the majority of affected adults remain undiagnosed, presenting instead with fatigue, morning headaches, and poor concentration that rarely prompt investigation. For people on Mounjaro, OSA occupies a specific clinical position: its symptoms are easily attributed to treatment side effects, making it even less likely to be identified; its bidirectional relationship with obesity means tirzepatide may be directly addressing one of its root causes; and the SURMOUNT-OSA trial (Malhotra et al., 2024) demonstrated AHI reductions of approximately 50% – results the investigators described as unprecedented for any single intervention. Beyond the Mounjaro context, OSA systematically disrupts the nocturnal repair window in which the majority of skin collagen synthesis, growth hormone secretion, and barrier recovery occur – making it directly relevant to treatment outcomes across the clinic’s aesthetic portfolio.

Obstructive sleep apnoea occurs when the muscles of the upper airway – the pharyngeal dilators that hold the throat open during wakefulness – relax during sleep and allow the airway to narrow or collapse. The resulting obstruction stops airflow, causing oxygen saturation to fall until a brief arousal (usually too short to be consciously recalled) restores muscle tone, clears the obstruction, and allows breathing to resume. In moderate-to-severe OSA, this sequence repeats 15 to over 100 times per hour across the night – each episode a miniature ischaemia-reperfusion event, each arousal fragmenting sleep architecture before the person has descended into the deeper stages their body requires. ^[16]

How OSA Is Measured and Classified

Severity is quantified by the apnoea-hypopnoea index (AHI), which counts the number of obstructive events per hour of sleep. The clinical thresholds used in the UK and internationally are: mild (AHI 5–14), moderate (15–29), and severe (AHI ≥30). Events per hour is the standard metric, but emerging evidence suggests the depth and cumulative duration of desaturation – the hypoxic burden – may better predict cardiovascular outcomes than event frequency alone, because organs respond differently to intermittent severe drops than to sustained mild ones. ^[16]

Diagnosis in UK clinical practice is made through either overnight polysomnography (PSG, the gold standard, conducted in a sleep laboratory with full physiological monitoring) or a home sleep apnoea test (HSAT, measuring oxygen saturation, nasal airflow, and chest movement without full EEG sleep staging). The latter is increasingly the first-line investigation given NHS capacity constraints, though it can underestimate AHI in mild presentations by missing events that occur during wake time inadvertently included in the recording window.

The Mechanism: Chronic Intermittent Hypoxia and Oxidative Stress

Each apnoeic episode follows a consistent biochemical pattern. Airway collapse → progressive oxygen desaturation → arousal → reoxygenation. That reoxygenation phase is not benign. The rapid restoration of oxygen to tissues that have just been hypoxic generates a burst of reactive oxygen species through mechanisms analogous to the ischaemia-reperfusion injury seen in myocardial infarction – on a smaller scale, but repeated dozens to hundreds of times per night. This is chronic intermittent hypoxia (CIH). ^[16]

In a 2024 clinical study published in Sleep and Biological Rhythms (Tokunou et al.), 42 newly diagnosed severe OSA patients (mean AHI 57.9 events/hour) showed oxidative stress markers (d-ROMs, a measure of serum hydroperoxide concentration) above normal range at baseline, with antioxidant capacity (BAP) below normal range. Critically, the higher the baseline AHI and oxygen desaturation index, the greater the subsequent reduction in d-ROMs following CPAP treatment – confirming a direct, dose-dependent relationship between apnoea severity and oxidative stress burden – with the most severely affected patients showing the greatest post-treatment reductions, though overall group-level d-ROM changes did not reach statistical significance. ^[16]

The ROS generated by CIH activate hypoxia-inducible factor 1-alpha (HIF-1α) and NF-κB – the same pro-inflammatory transcription factor activated by adipose-derived inflammation and UV radiation described in the skin ageing entities of this knowledge base. Downstream effects include elevated IL-6, TNF-alpha, and C-reactive protein. OSA therefore adds an independent and continuous inflammatory burden on top of any obesity-related inflammation already present – the two compounds one another rather than being interchangeable explanations for the same signal. ^[16]

The Undiagnosed Majority – and Why Women Are Particularly Missed

The scale of the diagnostic gap in the UK is striking when the numbers are placed alongside each other. A 2026 population-based study published in Thorax (CPRD primary care records linked to Hospital Episode Statistics, covering approximately 25% of the UK population) found diagnosed OSA prevalence in England in 2019 was 1.40% – approximately 622,528 people. ^[14] The same study reported that diagnosed prevalence “remained substantially lower than published estimates of symptomatic frequency” and explicitly called for initiatives to increase diagnosis rates. Against that 1.40% diagnosed figure, the OSA Partnership Group’s comprehensive review – drawing on multiple UK epidemiological sources – estimates that approximately 5% of adults aged 30–70 have moderate-to-severe OSA on sleep study, with a further 20% having mild OSA: 25% in total, representing approximately eight million people. ^[13] A 2024 England-specific occupational prevalence study published in Sleep Advances estimated overall OSA prevalence at 17.8% (95% CI 15.9–19.9%) for adults aged 40–64. ^[6]

Across these sources, the consistent picture is a diagnosed prevalence of roughly 1–2% against a true prevalence of 17–25% – meaning the overwhelming majority of people with OSA in the UK have no formal diagnosis. In the obese adult population specifically, the figures are sharper: a 2021 UK population analysis using the CPRD database (Erridge et al., Obesity Surgery, Imperial College London, n=276,600) found class III obesity conferred 3.77 times higher odds of OSA compared with normal weight, with an independent dose-response relationship across BMI class. ^[2]

The gap between prevalence and diagnosis is driven by more than low clinical awareness. It is partly structural: OSA is culturally and diagnostically associated with a specific presentation – a middle-aged, overweight man who snores audibly and is witnessed stopping breathing by a partner – that a substantial proportion of affected people, particularly women, do not fit. Women with OSA more frequently present with fatigue, morning headaches, low mood, and insomnia-type symptoms rather than the classic snoring and witnessed apnoeic episodes. Female bed partners of women with OSA report fewer witnessed events than male bed partners report for men, reducing the chance of the condition being raised unprompted. The Thorax 2026 study confirmed sex variation in diagnosed rates, consistent with the well-documented pattern of female under-investigation. ^[14]

For Mounjaro practitioners, this data creates a directly useful clinical frame. The client population is predominantly female, many in the 40–65 age bracket where OSA prevalence in women rises sharply post-menopause. Fatigue in early Mounjaro treatment is expected and frequently attributed to caloric restriction or GI side effects – which means the most common symptom of undiagnosed OSA is the symptom least likely to prompt further investigation in this population. The diagnostic gap is not simply a public health abstraction; it is active in the consulting room.

Clinical Pearl The client who is several months into Mounjaro treatment, past the dose-escalation phase, eating and sleeping tolerably – but still persistently exhausted – is the one who warrants a specific conversation about sleep quality and, if appropriate, a prompt toward GP assessment. OSA does not announce itself.

What OSA Does to the Skin

OSA’s effect on skin operates through two converging mechanisms that are worth distinguishing, because they respond to different interventions.

The first is the CIH-driven ROS pathway described above. A 2023 study published in Respiratory Physiology & Neurobiology (Zhang et al.) examined the effect of chronic intermittent hypoxia on collagen synthesis in mouse genioglossus muscle and found that CIH directly impaired collagen production via ROS accumulation – and that antioxidant intervention reversed the impairment. The mechanism is biologically plausible in human dermal fibroblasts given shared ROS sensitivity, but has not been directly demonstrated in skin tissue. ^[19] The mechanism is consistent with the fibroblast oxidative stress narrative detailed in the OXPHOS entity: ROS damage the OXPHOS complexes that power collagen synthesis, while simultaneously activating the MMP-driven degradation cascade. The skin of someone with uncontrolled moderate-to-severe OSA is receiving a nightly oxidative injury to its fibroblast population, independently of sun exposure, glycation, or any other ageing mechanism.

The second mechanism is sympathetic nervous system activation. Each arousal during an apnoeic event triggers an acute sympathetic discharge – a brief but real surge in adrenaline and cortisol. In severe OSA, nocturnal cortisol patterns are substantially disrupted, with the normal overnight nadir replaced by repeated spikes that interfere with the anti-inflammatory cortisol rhythm. The sympathetic surges also drive cutaneous vasoconstriction, reducing dermal blood flow and nutrient delivery during the window when skin perfusion should be at its peak. ^[11]

Visible correlates noted in the dermatology literature include periorbital darkening and oedema (driven by impaired nocturnal venous drainage and increased hydrostatic pressure), chronic facial pallor, and a dull skin surface texture consistent with impaired barrier recovery. Associations have been documented between OSA and inflammatory skin conditions including psoriasis and atopic dermatitis, mediated through elevated systemic IL-1, IL-6, IL-12, and TNF-alpha – inflammatory cytokines that both exacerbate these conditions and are themselves amplified by OSA-driven sleep disruption. ^[11] The upstream driver is NF-κB activation: a controlled study measuring NF-κB binding activity in circulating neutrophils found 4.8-fold greater activity in mild-to-moderate OSA patients and 7.9-fold greater activity in severe OSA patients compared to matched controls – a dose-response relationship that directly implicates apnoea severity as the inflammatory input. ^[4]

The Nocturnal Repair Window

The skin’s primary regenerative activity is concentrated in sleep, and specifically in the deep stages of it. During N3 slow-wave sleep, growth hormone reaches its largest secretory pulse of the twenty-four-hour cycle – in young adults, GH release during sleep accounts for up to two-thirds of total daily GH output, with the most reproducible pulse occurring shortly after sleep onset in association with the first N3 period. ^[17] GH drives IGF-1 production in the liver and locally in skin tissue, and IGF-1 is the principal growth factor stimulating fibroblast collagen synthesis. Cortisol reaches its nadir in the early hours of the night, removing its inhibitory effect on fibroblast activity and on barrier lipid synthesis. Melatonin, rising through the first half of the night, coordinates antioxidant enzyme activity and DNA repair – specifically addressing the UV-induced oxidative damage that accumulated during the day. ^[8]

Cutaneous blood flow increases as core body temperature falls and peripheral vasodilation compensates, improving dermal perfusion and nutrient delivery. Keratinocyte proliferation follows a circadian peak in the early hours of the morning. Skin permeability – measured as transepidermal water loss – rises in the evening and overnight, reaching its daily maximum during the night. ^[18] This is not barrier failure; it is the opening of the transcutaneous delivery window that makes overnight application of actives more effective than daytime application, and reflects the stratum corneum’s circadian rhythm of aquaporin-3 regulation and lipid processing activity. The barrier is not passively losing water – it is actively remodelling. ^[8]

This is the biological framework our nighttime skin rejuvenation article describes – the sleep window as the skin’s primary repair period, and the mechanisms that make it one. OSA disrupts this window directly and specifically. Apnoeic arousals fragment N3 sleep preferentially, because the greatest pharyngeal muscle relaxation – and therefore the greatest airway collapse susceptibility – occurs precisely during slow-wave sleep. The consequence is not simply that a client with OSA sleeps poorly in a general sense; it is that the specific stage of sleep in which the GH/IGF-1 axis drives collagen synthesis, cortisol is at its lowest, and melatonin coordinates repair is the stage being most actively and repeatedly interrupted. ^[5]

Every professional collagen-stimulating treatment – iPRF, RF microneedling, thulium laser – delivers signals that expect functional fibroblasts operating within a competent nocturnal repair window to consolidate results over the following nights. An unresolved OSA reduces the efficacy of that window in proportion to its severity, every night between sessions.

The Obesity–OSA Bidirectional Loop

The relationship between obesity and OSA is not simply that obesity causes OSA mechanically through fat deposition in upper airway tissues – though it does. It is bidirectional in a way that is clinically important, and the metabolic pathway is better understood through leptin and insulin resistance than through the ghrelin mechanism that often appears in simplified accounts.

The foundational sleep restriction evidence comes from Spiegel et al. (2004, Annals of Internal Medicine): in healthy young men, experimental restriction to four hours of sleep per night produced an 18% reduction in leptin (P=0.04), a 28% increase in ghrelin (P<0.04), a 24% increase in hunger ratings, and a 33–45% increase in appetite specifically for calorie-dense, high-carbohydrate foods. ^[12] This establishes sleep fragmentation as an independent driver of appetite dysregulation – but it is important to note this was experimental total sleep restriction in healthy adults, and the evidence that OSA-specific sleep fragmentation produces the same ghrelin response is considerably less consistent; a 2021 meta-analysis pooling seven controlled studies found no significant difference in ghrelin levels between OSA patients and controls overall. ^[15]

The more robust hormonal mechanism in OSA is through leptin resistance. OSA patients show elevated circulating leptin disproportionate to their BMI – a pattern that some researchers interpret as consistent with leptin resistance, in which the satiety signal is present but the hypothalamic response to it is blunted, though a causal relationship has not been definitively established. ^{[7] [3]} OSA also independently worsens insulin resistance through the intermittent hypoxia pathway, contributing to the same metabolic deterioration that makes weight management harder. The net effect is a metabolic environment that works against dietary adherence and weight loss – not through a single clean hormonal mechanism, but through compounding impairments to satiety signalling and glucose regulation.

Tirzepatide’s dual GIP/GLP-1 mechanism addresses the mechanical end of this loop directly. As adipose loading of the upper airway reduces with weight loss, airway geometry and collapse resistance improve. In SURMOUNT-OSA, participants lost an average of approximately 20% of body weight over 52 weeks, and investigators noted that AHI improvement appeared greater than weight loss magnitude alone would predict – suggesting possible additional effects of GLP-1 and GIP receptor activity on respiratory drive or airway muscle tone, though the mechanistic evidence for this remains preliminary. ^[10]

SURMOUNT-OSA: The Evidence

SURMOUNT-OSA was a 52-week Phase 3 randomised, double-blind, placebo-controlled trial (Malhotra et al., 2024; ClinicalTrials.gov NCT05412004) conducted across two parallel studies. Trial 1 enrolled adults with moderate-to-severe OSA (AHI ≥15 events per hour) and obesity who were not receiving positive airway pressure therapy at baseline. Trial 2 enrolled adults with the same OSA severity and obesity who were established on and continuing positive airway pressure (PAP) therapy. Both trials randomised participants 1:1 to tirzepatide at the maximum tolerated dose (10 mg or 15 mg weekly) or placebo for 52 weeks, with lifestyle intervention for weight management throughout. The primary endpoint was change in AHI from baseline to week 52. Mean baseline AHI was 51.5 events per hour in Trial 1 and 49.5 events per hour in Trial 2 – both firmly in the severe range. ^{[10] [1]}

Results were consistent across both trials. In Trial 1, tirzepatide produced a mean AHI reduction of 25.3 events per hour (95% CI −29.3 to −21.2) versus 5.3 events per hour with placebo, giving an estimated treatment difference of −20.0 events per hour (95% CI −25.8 to −14.2; P<0.001). In Trial 2, tirzepatide produced a mean AHI reduction of 29.3 events per hour (95% CI −33.2 to −25.4) versus 5.5 events per hour with placebo, for a treatment difference of −23.8 events per hour (95% CI −29.6 to −17.9; P<0.001). ^[10] Expressed as a proportion of baseline severity, these reductions represent approximately 49% and 59% respectively – meaning a participant entering Trial 1 with severe OSA (AHI 51.5) would, on average, move into the mild range. All prespecified key secondary endpoints showed statistically significant improvements with tirzepatide versus placebo, including hypoxic burden, high-sensitivity C-reactive protein (hsCRP; approximately 40% reduction in Trial 1 and 48% in Trial 2 versus placebo), systolic blood pressure (−9.5 mmHg versus −1.8 mmHg in Trial 1), and patient-reported sleep impairment and disturbance scores. [pubmed.ncbi.nlm.nih.gov/38912654/] The cardiometabolic secondary findings were further analysed in a prespecified secondary analysis published in Nature Medicine (Malhotra et al., January 2026), confirming that improvements in insulin resistance (assessed by the Homeostatic Model Assessment of Insulin Resistance, HOMA-IR) were mediated through both weight reduction and AHI resolution as independent pathways. ^[9]

Two important caveats apply. First, tirzepatide does not currently hold a specific MHRA licence for the treatment of OSA in the UK. CPAP therapy and clinically supervised weight management remain the NICE first-line interventions. SURMOUNT-OSA provides robust Phase 3 evidence of meaningful benefit, but it is properly understood as a significant secondary benefit in a population already receiving tirzepatide for obesity – not grounds for prescribing it with OSA as the primary indication. Second, the trial was funded by Eli Lilly and Company, with four of the named authors employed by Eli Lilly at the time of publication; this is standard for industry-funded Phase 3 development programmes but is relevant context for interpreting the magnitude of reported benefits. ^[10]