Acupuncture-related peripheral stimulation as a candidate neuromodulatory model of insomnia: clinical evidence, sleep-wake circuitry, and translational limits.

Acupuncture-related peripheral stimulation is often discussed as a non-pharmacological option for insomnia disorder, but its relevance to sleep neuroscience depends on more than improvement in sleep questionnaires. This critical narrative Review evaluates whether acupuncture and related acupoint-based stimulation methods can serve as testable peripheral models of sleep-wake and hyperarousal circuitry. Across clinical studies, the most consistent signal is improvement in subjective sleep quality and insomnia severity in selected populations. Evidence for objective sleep architecture, multiday sleep-wake stability, relapse prevention, and biomarker-mediated clinical response remains less secure. Human neuroimaging studies provide emerging but still associative evidence involving locus coeruleus, hypothalamic, insular, limbic-prefrontal, and thalamocortical networks. Electrophysiological, autonomic, endocrine, neurochemical, and microbiota-gut-brain findings are biologically plausible, but their proximity to human chronic insomnia disorder varies substantially. Safety is generally favorable when appropriately delivered, although adverse-event reporting remains inconsistent and comparative cost-effectiveness against CBT-I or pharmacotherapy is unestablished. We propose that acupuncture-related stimulation should currently be evaluated as an adjunctive, preference-sensitive, and mechanistically testable approach rather than as a replacement for cognitive behavioral therapy for insomnia. Its translational credibility will depend on credible comparators, objective sleep physiology, expectancy assessment, and prespecified mediation analyses.