Herbal Sleep Aids Show Promise for Older Adults With Insomnia, but Evidence Quality Raises Red Flags

A sweeping analysis of clinical trials in China has found that adding commercial Chinese polyherbal preparations to conventional sleep medication may improve sleep quality and reduce reported side effects in older adults with primary insomnia. The systematic review and meta-analysis, published in Frontiers in Pharmacology by researchers affiliated with Changchun University of Chinese Medicine, pooled data from sixteen randomized controlled trials involving 1,353 participants aged 60 to 89. Yet the authors themselves urge caution: the certainty of the evidence for efficacy outcomes was rated low to very low, and a sophisticated statistical tool revealed that one of the headline findings may be unreliable.

The team searched seven biomedical databases, including PubMed, Embase, the Cochrane Library and four Chinese-language databases, for randomized controlled trials published up to November 2025. From 4,392 initial records, sixteen trials conducted in China between 2011 and 2025 met the strict eligibility criteria. Only trials of officially marketed, standardized multi-ingredient herbal products—known as commercial Chinese polyherbal preparations, or CCPPs—combined with conventional hypnotic drugs were included. Hospital-prepared formulas, individualized herbal decoctions, and non-pharmacological interventions such as acupuncture were excluded. The comparator in every trial was biomedical monotherapy, typically benzodiazepines such as estazolam and alprazolam or non-benzodiazepines such as zopiclone and eszopiclone, which are first-line drugs for geriatric insomnia.

The primary outcome was sleep quality measured by the Pittsburgh Sleep Quality Index, a validated 0-to-21-point questionnaire. Across eight trials encompassing 630 participants, combination therapy was associated with a significantly lower PSQI score, with a mean difference of −2.09 points (95 percent confidence interval −2.62 to −1.57). On its face, that suggests meaningful symptomatic improvement over hypnotic drugs alone. However, the between-study heterogeneity was extreme—an I-squared statistic of 90 percent—prompting the authors to recommend considerable caution when interpreting the pooled estimate. A related measure, the Sleep Dysfunction Rating Scale, showed a directionally favorable but statistically non-significant reduction across three studies, with similarly high heterogeneity.

Secondary outcomes painted a more complicated picture. The total clinical effectiveness rate, a dichotomous endpoint derived from symptom-score reduction thresholds, appeared strongly favorable to the combination approach: across fifteen studies, the risk ratio was 1.21 (95 percent confidence interval 1.15 to 1.27), with low heterogeneity. The proportion of patients rated cured or markedly effective rose from 47.6 percent in the monotherapy group to 64.7 percent in the combination group, and treatment failure fell from 23.8 percent to 7.8 percent. But the P-curve analysis—a technique that examines the distribution of statistically significant p-values to detect whether a body of findings reflects genuine evidential value or selective reporting—delivered a striking verdict. While the PSQI results showed robust evidential value with 99 percent power, the total clinical effectiveness rate showed insufficient evidential value, with only 9 percent power, implying potential publication bias or p-hacking behind that superficially impressive result.

Safety findings were among the most consistent in the review. Eleven trials reporting adverse events, covering 1,006 participants, showed remarkably low heterogeneity (I-squared of 0.4 percent). Documented adverse events occurred in 11.3 percent of the combination group (57 of 506 patients) versus 24.4 percent of the monotherapy group (122 of 500), yielding a risk ratio of 0.47—a 53 percent relative reduction. The events most commonly reported were mild nausea, dizziness and somnolence, all described as transient. The GRADE framework rated the certainty of evidence for adverse events as moderate, the highest rating of any outcome in the analysis.

The safety picture, however, comes with major caveats that the authors detail candidly. None of the included trials prospectively assessed geriatric-specific high-risk outcomes such as falls, cognitive impairment, excessive sedation, drug dependence or withdrawal reactions—the very complications that make long-term hypnotic use problematic in older adults. No study systematically monitored hepatic or renal function, and none investigated potential drug-drug interactions between botanical metabolites and prescription hypnotics. Four trials reported that adjunctive herbal therapy allowed lower doses of biomedical hypnotics, which the authors speculate might partly explain the lower adverse-event rate, but this observation rests on a small subset of studies. Selective underreporting of side effects may also have inflated the apparent safety advantage.

Methodological quality of the primary trials was uniformly poor. Under the Cochrane Risk of Bias 2 tool, every one of the sixteen studies was judged at overall high risk of bias. Not a single trial blinded participants or researchers to the treatment allocation, a serious problem given that the main outcomes relied on subjective symptom assessment, opening the door to performance and detection bias. Eight studies did not specify their randomization method, five could not demonstrate prespecified outcome reporting because they lacked prospective trial registration, and nearly all had no registration at all. These flaws drove the GRADE certainty ratings down to low or very low for the efficacy outcomes, even as the pooled estimates remained nominally significant after trim-and-fill adjustment for missing studies.

The subgroup analyses offered a potentially important clinical clue. When patients were stratified by disease duration, heterogeneity in the PSQI outcome vanished entirely (I-squared of 0 percent) in the subgroup with insomnia lasting less than one year, while remaining severe in the one-to-three-year subgroup, though the between-subgroup difference itself was not statistically significant. For treatment duration, the difference between subgroups was significant: trials lasting more than eight weeks showed no heterogeneity, whereas shorter trials showed substantial variability. The authors interpret this as evidence that early intervention with integrated therapy may produce more consistent results, while chronic insomnia may involve harder-to-reverse neurobiological changes. An exploratory analysis by traditional Chinese medicine syndrome pattern found no significant between-group differences, though individual subgroups such as heart-liver blood deficiency showed significant pooled benefit; most syndrome subgroups contained only one or two trials, limiting statistical power, and syndrome classification relied on product indications rather than patient-specific diagnosis.

The rationale for combining approaches is pharmacologically plausible. Conventional hypnotics act mainly on the GABA-ergic neurotransmitter system to produce rapid sedation, whereas CCPPs follow the traditional Chinese medicine principle of syndrome differentiation, aiming to regulate visceral function, qi-blood and yin-yang to restore homeostasis. Preclinical studies have suggested some of these preparations may modulate the gut-brain axis and tryptophan metabolism. In China, where more than 190 million people are aged 65 and above and sleep disturbance prevalence in that cohort ranges from 40 to 70 percent, the search for safer adjuncts carries real public health weight, given that long-term hypnotic use in the elderly is associated with dependency, cognitive blunting, falls and rebound insomnia.

Still, the authors’ conclusions are deliberately measured. All sixteen trials were conducted in China, limiting generalizability to other populations, and the universal absence of blinding constitutes a critical methodological gap even if it is practically difficult to disguise botanical preparations. The meta-analysis, registered prospectively with PROSPERO and conducted under PRISMA 2020 guidelines, concludes that combination therapy may help improve sleep quality and may reduce reported adverse events in elderly patients with primary insomnia—but that clinicians should prioritize scale-based outcomes like the PSQI when weighing the literature, since the total clinical effectiveness rate cannot be trusted. What is needed next, the team argues, are large-scale, multicenter, double-blind, placebo-controlled randomized trials that also track falls, cognition, sedation, dependence and organ function. Until such studies arrive, the promise of polyherbal adjuncts for aging insomniacs remains an intriguing but unproven hypothesis.

Subject of Research: Systematic review and meta-analysis of commercial Chinese polyherbal preparations combined with biomedicine for primary insomnia in elderly patients

Article Title: Efficacy and safety of commercial Chinese polyherbal preparations combined with biomedicine for elderly patients with primary insomnia: a systematic review and meta-analysis of randomized controlled trials

Article References: Wu, Y., Liu, F., Shi, M., Yu, L., Zhang, Y., Cui, H., Zhang, R., Xu, P., & Nan, H. (2026). Efficacy and safety of commercial Chinese polyherbal preparations combined with biomedicine for elderly patients with primary insomnia: a systematic review and meta-analysis of randomized controlled trials. Frontiers in Pharmacology, 17, Article 1841014. https://doi.org/10.3389/fphar.2026.1841014

Image Credits: AI Generated

DOI: 10.3389/fphar.2026.1841014

Keywords: primary insomnia, elderly patients, commercial Chinese polyherbal preparations, meta-analysis, systematic review, PSQI, adverse events, publication bias, traditional Chinese medicine, GRADE, P-curve analysis, randomized controlled trials