An umbrella review sits at the very top of the evidence hierarchy. Rather than analyzing individual clinical trials, it systematically collects and critically appraises all of the existing systematic reviews on a topic, effectively auditing the audits. The research team, led by Adrian Kużdżał of the University of Rzeszów in Poland and including Edzard Ernst of the University of Exeter, a longtime and often pointed critic of unsubstantiated complementary therapies, searched eight major databases including PubMed, MEDLINE, Embase, the Cochrane Database of Systematic Reviews, Web of Science, Scopus, PEDro and Epistemonikos. Their search window stretched from January 2000 to December 2025, capturing a quarter century of accumulated review literature on dry needling delivered with or without usual care by a range of healthcare professionals for musculoskeletal or non-musculoskeletal pain and dysfunction in human subjects. Narrative and non-systematic reviews were excluded, and the team strictly followed the PRIOR reporting guidelines for overviews of reviews.

The scale of the enterprise is striking. The researchers identified 75 systematic reviews that met their eligibility criteria, collectively covering 45,032 individual participants. That is an enormous evidence base by any standard, and it reflects just how much clinical and academic energy has been poured into dry needling over the past two decades. Yet the headline numbers tell a story of deep division within that literature. Fifty of the 75 reviews, or 66.6 percent, reported conclusions favoring dry needling. Seventeen reviews, or 22.6 percent, came down on the fence with equivocal conclusions, while eight reviews, or 10.6 percent, reported outright negative conclusions. On the surface, two thirds of the review literature appears to endorse the technique, and it is easy to see how advocates might cite that figure as proof of effectiveness.

But the authors dug one level deeper, and this is where the picture changes dramatically. Using the ROBIS tool, a validated instrument for assessing the risk of bias in systematic reviews, they found that 57 of the 75 reviews, a full 76 percent, demonstrated a high risk of bias across multiple domains. The problems clustered in the most consequential stages of the review process: study selection, where reviewers may cherry-pick which trials to include; data appraisal, where the quality of the underlying trials is judged; and synthesis, where results are pooled and interpreted. In other words, the machinery that is supposed to make systematic reviews trustworthy was itself frequently compromised. A review with high risk of bias in these domains can produce optimistic conclusions that simply do not survive rigorous scrutiny.

The most telling analysis concerns the minority of reviews that passed the quality test. Among the 18 systematic reviews judged to be at low risk of bias, the picture was far less rosy than the raw numbers suggested. Twelve of those 18, or 66.6 percent, still reported favorable conclusions, but five, or 27.7 percent, were equivocal and one, or 5.5 percent, was negative. Even among the best-conducted reviews, a third failed to find clear benefit, and the authors emphasize that the certainty of the evidence underpinning the favorable conclusions remained limited because of high risk of bias in the primary trials and substantial statistical heterogeneity between studies. Heterogeneity, in the language of meta-analysis, means that the pooled effect sizes extracted from the reviews varied widely across conditions, outcome measures and comparison groups, making it difficult to state with confidence what a typical patient should expect.

The umbrella review also examined the degree to which the 75 reviews were recycling the same primary trials, a problem known in evidence synthesis as overlap. When many reviews analyze overlapping pools of studies, the apparent volume of evidence is inflated and the reviews are not independent tests of the hypothesis. The researchers quantified this using the Corrected Covered Area, or CCA, a standard metric for overlap assessment. The result was a CCA of 1.09, which the authors classify as slight overlap. That finding is genuinely reassuring in one respect: the 75 reviews are largely built on different combinations of primary studies rather than repeatedly reanalyzing the same small trial set. The problem, then, is not redundancy but quality, since the sheer breadth of the literature has not translated into methodological rigor.

Safety is where the review delivers perhaps its most practical warning. Dry needling involves penetrating the skin with needles, and like any invasive procedure it carries potential for adverse effects, ranging from common transient soreness and bleeding at the needle site to rarer but more serious events such as pneumothorax when needles are placed near the chest wall. Yet the review found that only 36 of the 75 systematic reviews, or 48 percent, reported any adverse-effect data at all. The remaining 39 reviews, more than half, failed to provide any information on harms. This pattern of underreporting is a well-recognized blind spot in the complementary and manual therapy literature, where enthusiasm for benefit often outpaces systematic attention to risk. Patients and clinicians cannot make genuinely informed decisions when half of the evidence synthesis literature is silent on safety.

Putting all of this together, the authors conclude that no definitive judgments about the clinical effectiveness of dry needling in reducing pain and disability can currently be drawn, and that the existing findings should be interpreted with caution. That is not the same as declaring the technique useless; it is a statement about the state of the evidence. The favorable conclusions reported by many reviews may reflect real effects, but they may equally reflect biased trial design, small samples, unblinded outcome assessment, publication bias and the methodological weaknesses that pervade three quarters of the review literature itself. The authors call for high-quality, condition-specific systematic reviews and randomized clinical trials to resolve the uncertainty, and their work is registered in PROSPERO under identifier CRD420251058215, underscoring the transparency of their own protocol.

For clinicians, the implications are nuanced. Dry needling is often used for conditions such as myofascial pain syndrome, low back pain, tension-type headache, cervicogenic headache and fibromyalgia, and outcome measures in the reviewed literature included familiar instruments such as the Numeric Pain Rating Scale, the Visual Analog Scale, the Neck Disability Index, the Oswestry Disability Index, the Roland-Morris Disability Questionnaire and the WOMAC osteoarthritis index. The umbrella review does not show that the technique harms patients in the conditions studied, and the slight overlap analysis suggests the field has genuinely explored a wide range of clinical questions. But a therapy whose evidence base is dominated by high-risk-of-bias reviews cannot be presented to patients as proven, and the inconsistent safety reporting means that even the risk profile is incompletely mapped.

For the broader public, the study is a masterclass in why the phrase systematic review alone should not end an argument. Seventy-five reviews and forty-five thousand participants sound like overwhelming evidence, yet the umbrella review demonstrates that the architecture of that evidence, not just its quantity, determines what can be believed. The work, funded by the Statutory Research Fund of the Collegium Medicum at the University of Rzeszów with support from the Polish Ministry of Science and Higher Education, and published open access under a Creative Commons license, offers a comprehensive map of where dry needling research stands and where it must go. Until better trials and better reviews arrive, the needles may keep going in, but the verdict on dry needling remains, scientifically speaking, an open question.

Subject of Research: Effectiveness and safety of dry needling for pain and dysfunction, evaluated through an umbrella review of systematic reviews

Article Title: How effective is dry needling? an umbrella review

Article References: Kużdżał, A., Ernst, E., Trybulski, R., & Posadzki, P. (2026). How effective is dry needling? an umbrella review. BMC Complementary Medicine and Therapies. https://doi.org/10.1186/s12906-026-05607-9

Image Credits: AI Generated

DOI: 10.1186/s12906-026-05607-9

Keywords: dry needling, umbrella review, systematic review, myofascial trigger points, pain, disability, risk of bias, ROBIS, adverse effects, physical therapy, evidence-based medicine, musculoskeletal conditions