Bridging Conventional Sleep Medicine and Root-Cause Care: A Clinical Review

Yoon Hang Kim, MD, MPHBoard-Certified in Preventive Medicine | Integrative & Functional Medicine Physician

Introduction: A Common Complaint, an Underappreciated System

Insomnia is among the most frequently reported symptoms in ambulatory medicine, yet it is often addressed as an isolated nighttime nuisance rather than as a signal of broader physiologic imbalance. Population-based estimates suggest that roughly one-third of adults report at least occasional insomnia symptoms in a given year, and that clinically significant, chronic insomnia disorder affects on the order of 10 to 20 percent of adults worldwide, with a global burden estimated at more than 850 million affected individuals and a disproportionate impact on women and older adults [1,2]. Once established, chronic insomnia tends to persist: longitudinal data indicate that symptoms continue in roughly 40 percent of cases over a five-year follow-up period [1]. Despite this burden, insomnia is frequently under-recognized and under-coded in primary care relative to its true population prevalence, meaning a substantial share of affected individuals never receive a structured evaluation [3].

From an integrative and functional medicine standpoint, insomnia is best understood not as a single disease entity but as a final common pathway through which multiple upstream disturbances can express themselves: dysregulated stress physiology, circadian misalignment, gut-brain axis disruption, and low-grade systemic inflammation. A root-cause framework does not discard conventional, evidence-based sleep medicine; rather, it situates first-line therapies within a broader systems-biology context and asks why the sleep system has become unstable for a given individual.

The Conventional Foundation: CBT-I as First-Line Therapy

Any integrative discussion of insomnia should begin from, not around, the strongest existing evidence base. Cognitive behavioral therapy for insomnia (CBT-I), a multicomponent approach combining stimulus control, sleep restriction, cognitive restructuring, and relaxation training, is recognized by the American College of Physicians and multiple sleep medicine societies as the first-line treatment for chronic insomnia disorder, with effect sizes and durability of benefit that exceed those of pharmacotherapy over the long term [4]. Component network meta-analyses continue to refine which elements of CBT-I drive the greatest benefit, but the multicomponent package remains the recommended starting point before or alongside pharmacologic or nutraceutical strategies [4]. An integrative approach to insomnia is therefore additive to CBT-I, not a substitute for it, and clients who have not yet had access to structured behavioral sleep treatment should generally be offered it as a foundational intervention.

An Integrative Root-Cause Framework

Hyperarousal and HPA Axis Dysregulation

The dominant pathophysiologic model of chronic insomnia is one of 24-hour physiologic hyperarousal, in which heightened cognitive, emotional, and autonomic activation prevents the nervous system from disengaging at night even when the drive for sleep is present [5]. This hyperarousal is closely tied to activity of the hypothalamic-pituitary-adrenal (HPA) axis. Meta-analytic data comparing individuals with chronic insomnia to good sleepers show a pattern of elevated cortisol output across the day and particularly around bedtime, consistent with a stress-axis system that has failed to downshift appropriately in the evening [6]. Because the HPA axis integrates input from psychological stress, blood glucose regulation, circadian signaling, and inflammatory tone, an integrative evaluation of insomnia often includes a functional assessment of stress physiology, using tools such as diurnal salivary cortisol profiling, alongside dietary, mind-body, and adaptogenic strategies aimed at restoring appropriate HPA rhythmicity rather than simply sedating the nervous system at bedtime [7].

Functional Testing: Mapping the Cortisol Cycle, Melatonin, and Neurotransmitters

Because the hyperarousal model implicates stress physiology so directly, an integrative insomnia workup often incorporates functional testing that characterizes the diurnal cortisol curve rather than relying on a single random cortisol value. Diurnal salivary cortisol profiling, in which the individual collects several saliva samples across the day, allows the clinician to see whether the normal pattern, a robust cortisol awakening response followed by a steady decline to a low evening nadir, is intact, blunted, phase-shifted, or elevated at night in a way that would keep the nervous system in a bedtime-inappropriate state of arousal [7]. Peer-reviewed work supports diurnal cortisol profiling as a window into HPA axis function, and integrative frameworks use it to distinguish, for example, a client whose insomnia is driven by an abnormally high late-evening cortisol from one whose pattern suggests a flattened, dysregulated curve [7].

A more comprehensive option that has become popular in functional and integrative practice is the Dried Urine Test for Comprehensive Hormones (DUTCH). Using dried urine samples collected at four timed points across a single day, this panel measures free cortisol and cortisone across the diurnal cycle, the cortisol awakening response, and total cortisol metabolites, giving a more complete picture of both cortisol output and how the body clears it. Depending on the specific panel ordered, DUTCH testing also reports 6-hydroxymelatonin sulfate (a urinary metabolite reflecting melatonin production), oxidative stress markers such as 8-hydroxy-2'-deoxyguanosine (8-OHdG), and urinary organic-acid metabolites of key neurotransmitters, including homovanillic acid (a dopamine metabolite), vanillylmandelic acid (a metabolite of epinephrine and norepinephrine), and markers along the serotonin and tryptophan pathways [24,25]. In a client with insomnia, a low melatonin metabolite can support a trial of individualized melatonin timing, while a "tired and wired" pattern of catecholamine excess alongside low dopamine turnover can help direct which stress-physiology and neurotransmitter-support strategies to prioritize [24].

It is important to be transparent about the evidence base for these tools. The dried-urine methodology itself has been described in the peer-reviewed literature, and one published analysis found that dried-urine sampling on filter paper is a workable method for assessing cortisol and its metabolites [26]. At the same time, robust independent validation of the full commercial DUTCH panel, and of the clinical decision-making built on it, remains limited, and the model of discrete "adrenal fatigue" that these panels are sometimes marketed to diagnose is not an endorsed medical diagnosis. These tests are therefore best used as one hypothesis-generating input within a broader clinical picture, interpreted by a qualified clinician alongside history, examination, and, where appropriate, conventional laboratory work, rather than as a stand-alone basis for treatment [26].

Circadian Rhythm and Evening Light Exposure

A second pillar of the integrative model concerns circadian entrainment. Specialized retinal cells containing melanopsin are maximally sensitive to short-wavelength (blue) light in the 460 to 480 nanometer range and signal the suprachiasmatic nucleus, the body's master clock, to suppress pineal melatonin secretion when this light is present in the evening [8]. Experimental and meta-analytic evidence confirms that evening exposure to screens and LED lighting delays melatonin onset, prolongs sleep onset latency, and shifts circadian phase later, an effect that is measurable even at relatively low, ambient light levels [8,9]. From a clinical standpoint, this makes evening light hygiene, dimming household lighting, using blue-light-filtering settings on devices, and prioritizing morning bright-light exposure to anchor the circadian clock, a low-cost, mechanistically grounded intervention that complements rather than competes with CBT-I and pharmacologic melatonin support.

The Gut-Brain-Sleep Axis

A growing body of literature describes a bidirectional relationship between the gut microbiome and both circadian biology and sleep architecture. Host circadian genes shape the timing and composition of gut microbial populations, while microbial metabolites, including short-chain fatty acids and tryptophan derivatives, feed back to influence central clock gene expression and HPA axis reactivity [10,11]. Sleep deprivation itself alters microbial composition, and in turn, altered gut microbiota have been associated with disrupted sleep-wake regulation, suggesting a self-reinforcing cycle in individuals with chronic gastrointestinal dysfunction or dysbiosis [12]. Notably, a meaningful proportion of the body's melatonin is synthesized outside the pineal gland by intestinal enterochromaffin cells, and gut microbes can both stimulate this local melatonin production and be shaped by it, adding a plausible mechanistic link between gastrointestinal health and sleep quality that is frequently overlooked in conventional sleep evaluations [11]. This provides rationale for integrative clinicians to consider gastrointestinal history, and where indicated, functional stool or microbiome testing, as part of a comprehensive insomnia workup, particularly in clients with coexisting irritable bowel symptoms, food sensitivities, or a history of antibiotic-heavy medical care.

Systemic Inflammation

Sleep and inflammation are linked in both directions. A meta-analysis pooling more than seventy studies and over fifty thousand participants found that self-reported sleep disturbance is associated with higher circulating levels of C-reactive protein (CRP) and interleukin-6 (IL-6), two principal biomarkers of systemic inflammation [13]. Conversely, correcting insomnia through behavioral treatment appears to modestly reduce some of these same inflammatory markers, with a review of CBT-I trials reporting consistent CRP improvement across studies [14]. This bidirectional relationship is clinically relevant because it means chronic insomnia should be treated, in part, as a driver of downstream inflammatory and cardiometabolic risk, and that individuals with insomnia superimposed on autoimmune disease, mast cell activation syndrome, or other inflammatory conditions may experience mutual aggravation of both processes until the sleep disturbance itself is addressed.

Evidence-Informed Integrative Interventions

Magnesium

Magnesium has plausible mechanistic support for a role in sleep regulation through its action on GABA-A receptors and its influence on HPA axis activity. A recent, well-powered randomized, double-blind, placebo-controlled trial of magnesium bisglycinate (250 mg elemental magnesium daily) in 155 adults with self-reported poor sleep found a statistically significant, though modest, reduction in Insomnia Severity Index scores compared with placebo over four weeks [15]. Smaller crossover trials of higher-dose magnesium and of magnesium L-threonate have similarly reported improvements in sleep efficiency, sleep duration, and next-day mood, though effect sizes across the literature remain small to moderate and are most pronounced in individuals with lower baseline dietary magnesium intake [16,17].

Melatonin

Exogenous melatonin has one of the deeper evidence bases among integrative sleep agents. Pooled meta-analytic data across 19 to 26 randomized controlled trials consistently show that melatonin modestly reduces sleep onset latency and increases total sleep time compared with placebo, with dose-response modeling suggesting effects that increase up to roughly 4 mg per day and that are influenced by the timing of administration relative to the target sleep window [18,19]. The magnitude of benefit is smaller than that seen with prescription hypnotics, but melatonin carries a comparatively favorable long-term safety profile, and its greatest evidence of benefit for sleep-onset difficulty is seen when timing and dose are individualized rather than applied as a fixed, generic regimen [18,19].

Ashwagandha (Withania somnifera)

Ashwagandha, an adaptogenic botanical used traditionally in Ayurvedic medicine, has accumulating randomized controlled trial evidence for sleep benefit, plausibly mediated through cortisol reduction and GABAergic activity. A systematic review and meta-analysis of five randomized controlled trials totaling 400 participants found a statistically significant, small-to-moderate improvement in overall sleep quality with ashwagandha extract compared with placebo, with the strongest effects observed in individuals with a diagnosis of insomnia, at doses of 600 mg per day or greater, and with treatment courses of eight weeks or longer [20]. A dedicated randomized, placebo-controlled trial in adults with diagnosed insomnia and anxiety similarly found significant improvements in sleep onset latency, sleep efficiency, and subjective sleep quality with a standardized ashwagandha root extract over ten weeks [21].

Mind-Body and Mindfulness-Based Approaches

Mindfulness-based interventions occupy a useful middle ground between behavioral sleep medicine and integrative stress-reduction strategies. In a randomized clinical trial of older adults with moderate sleep disturbance, a structured mindfulness meditation program produced clinically meaningful improvements in sleep quality that were superior to a sleep hygiene education control at the end of treatment [22]. A separate three-arm randomized trial comparing mindfulness-based stress reduction and mindfulness-based therapy for insomnia against a self-monitoring control found significantly greater reductions in total wake time, pre-sleep arousal, and Insomnia Severity Index scores in both mindfulness arms, reinforcing the mechanistic link between cognitive-emotional hyperarousal and sleep continuity described earlier in this review [23]. These approaches are particularly well suited to clients whose insomnia is closely tied to rumination, anxiety, or an inability to downshift from daytime stress physiology at night.

Toward an Integrated Clinical Model

Taken together, the evidence supports a layered, individualized approach to insomnia care rather than a single algorithm. Structured behavioral therapy (CBT-I) remains the appropriate first-line intervention for most clients with chronic insomnia disorder. Layered onto this foundation, an integrative evaluation looks for and addresses the upstream drivers most relevant to a given individual: HPA axis dysregulation and hyperarousal, addressed through diurnal cortisol and, where indicated, comprehensive dried-urine (DUTCH-type) testing that also profiles melatonin and neurotransmitter metabolites, combined with adaptogenic support and mind-body practice; circadian misalignment, addressed through light hygiene and individualized melatonin timing; gut-brain axis disruption, addressed through gastrointestinal history and, where indicated, functional testing; and systemic inflammation, addressed by treating comorbid inflammatory conditions and recognizing insomnia itself as a modifiable inflammatory driver. This model does not ask whether conventional or integrative sleep medicine is correct; it asks which combination of evidence-based tools best fits the physiology of the individual client in front of the clinician.

Conclusion

Insomnia is rarely a disorder of the bedroom alone. It sits at the intersection of stress physiology, circadian biology, gastrointestinal health, and systemic inflammation, and durable improvement often requires attention to each of these systems rather than reliance on a single hypnotic agent. A functional and integrative medicine framework, applied alongside rather than instead of evidence-based behavioral sleep medicine, offers a coherent way to organize this complexity and to individualize care for clients whose sleep has not responded to a purely symptomatic approach.

References

1. Morin CM, Jarrin DC. Epidemiology of insomnia: prevalence, course, risk factors, and public health burden. Sleep Med Clin. 2022;17(2):173-191.

2. Benjafield AV, Sert Kuniyoshi FH, Malhotra A, Martin JL, Morin CM, Maurer LF, Cistulli PA, Pépin JL, Wickwire EM. Estimation of the global prevalence and burden of insomnia: a systematic literature review-based analysis. Sleep Med Rev. 2025;82:102121. doi:10.1016/j.smrv.2025.102121.

3. Pujol Salud J, García-Serrano C, de Entrambasaguas M, Malla Montagut M, Martínez Redondo J, et al. Primary care records and population prevalence of chronic insomnia: do they match? Healthcare (Basel). 2025;13(23):3152. doi:10.3390/healthcare13233152.

4. Dismantling cognitive-behavioural therapy for chronic insomnia in adults with or without comorbidities: a systematic review and component network meta-analysis. medRxiv. 2023.

5. Elder GJ, et al. Stress and the hypothalamic-pituitary-adrenal axis: how can the COVID-19 pandemic inform our understanding and treatment of acute insomnia? J Sleep Res. 2023.

6. HPA axis activity in patients with chronic insomnia: a systematic review and meta-analysis of case-control studies. Sleep Med Rev. 2022.

7. An integrative approach to HPA axis dysfunction: from recognition to recovery. Am J Med. 2025.

8. Efficacy of blue-light blocking glasses on actigraphic sleep outcomes: a systematic review and meta-analysis of randomized controlled crossover trials. Front Neurol. 2025.

9. Interventions to reduce short-wavelength ("blue") light exposure at night and their effects on sleep: a systematic review and meta-analysis. Sleep Adv. 2020;1(1):zpaa002.

10. The molecular interplay between the gut microbiome and circadian rhythms: an integrated review. Front Microbiol. 2025.

11. Bidirectional interactions between circadian rhythms and the gut microbiome. Appl Microbiol Biotechnol. 2025.

12. Li Y, Hao Y, Fan F, Zhang B. Clinical review: sleep, circadian rhythm, and gut microbiota. Sleep Med Rev. 2020.

13. Irwin MR, Olmstead R, Carroll JE. Sleep disturbance, sleep duration, and inflammation: a systematic review and meta-analysis of cohort studies and experimental sleep deprivation. Biol Psychiatry. 2016;80(1):40-52.

14. Savin KL, Clark TL, Perez-Ramirez P, Allen TS, Tristão Parra M, Gallo LC. The effect of cognitive behavioral therapy for insomnia (CBT-I) on cardiometabolic health biomarkers: a systematic review of randomized controlled trials. Behav Sleep Med. 2023;21(6):671-694. doi:10.1080/15402002.2022.2154213.

15. Schuster J, Cycelskij I, Lopresti AL, Hahn A. Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nat Sci Sleep. 2025;17. doi:10.2147/NSS.S524348.

16. Breus MJ, Hooper S, Lynch T, Hausenblas HA. Effectiveness of magnesium supplementation on sleep quality and mood for adults with poor sleep quality: a randomized double-blind placebo-controlled crossover pilot trial. Med Res Arch. 2024;12(7). doi:10.18103/mra.v12i7.5410.

17. Hausenblas HA, Lynch T, Hooper S, Shrestha A, Rosendale D, Gu J. Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: a randomized controlled trial. Sleep Med X. 2024;8:100121. doi:10.1016/j.sleepx.2024.100121.

18. Ferracioli-Oda E, Qawasmi A, Bloch MH. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS One. 2013;8(5):e63773.

19. Optimizing the time and dose of melatonin as a sleep-promoting drug: a systematic review of randomized controlled trials and dose-response meta-analysis. J Pineal Res. 2024. doi:10.1111/jpi.12985.

20. Cheah KL, Norhayati MN, Yaacob LH, Rahman RA. Effect of Ashwagandha (Withania somnifera) extract on sleep: a systematic review and meta-analysis. PLoS One. 2021;16(9):e0257843.

21. Langade D, Kanchi S, Salve J, Debnath K, Ambegaokar D. Efficacy and safety of Ashwagandha (Withania somnifera) root extract in insomnia and anxiety: a double-blind, randomized, placebo-controlled study. Cureus. 2019.

22. Black DS, O'Reilly GA, Olmstead R, Breen EC, Irwin MR. Mindfulness meditation and improvement in sleep quality and daytime impairment among older adults with sleep disturbances: a randomized clinical trial. JAMA Intern Med. 2015;175(4):494-501.

23. Ong JC, Manber R, Segal Z, Xia Y, Shapiro S, Wyatt JK. A randomized controlled trial of mindfulness meditation for chronic insomnia. Sleep. 2014;37(9):1553-1563.

24. Precision Analytical (DUTCH Test). DUTCH Complete and DUTCH Plus panels: measured analytes including diurnal free cortisol and cortisone, cortisol metabolites, cortisol awakening response, 6-hydroxymelatonin sulfate, 8-OHdG, and neurotransmitter organic-acid metabolites (HVA, VMA, 5-HIAA). Manufacturer test documentation. Accessed 2026.

25. Rupa Health. DUTCH Test (Dried Urine Test for Comprehensive Hormones): overview of measured hormones, cortisol rhythm, melatonin, and organic-acid neurotransmitter metabolites. Laboratory reference resource. Accessed 2026.

26. Newman M, Curran DA, Mayfield BP. Dried urine and salivary profiling for complete assessment of cortisol and cortisol metabolites. J Clin Transl Endocrinol. 2020;22:100243. doi:10.1016/j.jcte.2020.100243. (See also: Newman M, Curran DA. Reliability of a dried urine test for comprehensive assessment of urine hormones and metabolites. BMC Chem. 2021;15:18. doi:10.1186/s13065-021-00744-3.)

About Dr. Kim

Dr. Yoon Hang "John" Kim is a board-certified physician with more than twenty years of experience in preventive, integrative, and functional medicine. He completed an integrative medicine fellowship under Dr. Andrew Weil at the University of Arizona, holds certification in medical acupuncture from UCLA, and is a Scholar of the Institute for Functional Medicine. His clinical focus includes low-dose naltrexone therapy, autoimmune disease, chronic pain, integrative oncology, fibromyalgia, chronic fatigue syndrome, mast cell activation syndrome, and mold/biotoxin illness. He is the author of three books and more than twenty articles in these fields.

Professional site: www.yoonhangkim.com   |   Clinical practice: www.directintegrativecare.com