Exploring the efficacy of acupuncture for tension-type headache: a literature review and insights from traditional Chinese medicine

1. Introduction

Tension-type headache (TTH) is a prevalent primary headache disorder characterized by mild to moderate pressure or tension in the head [1, 2]. Its prevalence in the general population ranges from 30% to 78%, with a higher incidence observed in women compared to men [3, 4]. In China, the prevalence varies between 10.8% and 25.2% and is on the rise [5, 6]. TTH significantly impacts the disability-adjusted life years of young and middle-aged individuals [7], affecting mood, work performance and daily life. It not only diminishes quality of life and impairs physical and mental health [8] but also imposes a substantial economic burden on both society and families. Although current treatment options for TTH include antidepressants, these medications are often associated with adverse effects and poor tolerance, especially in elderly patients [9]. In addition, nonsteroidal anti-inflammatory drugs (NSAIDs) may cause gastrointestinal symptoms as well as liver and kidney toxicity [10].

Acupuncture, a significant component of Traditional Chinese Medicine (TCM), has demonstrated clinical efficacy and safety in managing various neurological disorders and pain-related conditions [11, 12]. Notably, its effectiveness in treating TTH is well-documented, with evidence indicating improvements in blood circulation in the head and neck region, a reduction in disease duration and a high level of patient satisfaction [13]. While previous reviews have addressed the efficacy and safety of acupuncture for TTH [14], they often lack detailed discussions on critical aspects such as acupoint selection, needle retention time, treatment duration, and underlying mechanisms.

In TCM, TTH is classified under the broader category of “headache”, with its earliest references found in The Yellow Emperor’s Classic of Internal Medicine (YECIM) scripts. According to YECIM, headaches are thought to result from external factors such as wind, cold, dampness and heat or from internal imbalances including dampness, heat, blood stasis, weakness and qi stagnation, which disrupt the overall balance of yin and yang in the body [15]. Ancient Chinese practitioners integrated theoretical concepts with clinical experience to classify headaches into various TCM syndromes, characterized by specific headache symptoms, accompanying signs and diagnostic indicators such as tongue appearance and pulse quality [16]. The treatment approaches, including herbal remedies and acupuncture, differ based on the specific TCM syndrome diagnosed. Notably, Zhang Zhongjing, a prominent TCM physician of the Han Dynasty, introduced an alternative diagnostic framework in his Treatise on Febrile Diseases. He categorized headaches based on their location in the meridians—Taiyang, Yangming, Shaoyang and Jueyin—rather than focusing on accompanying symptoms and tongue and pulse characteristics [17].

Acupuncture and herbal therapies are both essential elements of TCM, with acupuncture specifically focusing on the selection and combination of acupoints, each having distinct therapeutic effects. Ancient TCM practitioners, despite differing in their choice of acupoints for headache treatment, based their acupuncture prescriptions on their clinical experience and aligned them with relevant TCM syndromes and meridian theories [17]. This review aims to address these gaps by providing a detailed analysis of these factors from both TCM and Western medicine perspectives and proposes a preliminary therapeutic regimen to assist clinicians in effectively utilizing acupuncture for the treatment of TTH.

2. Modern application and clinical trials on acupuncture in TTH

We conducted a systematic search of PubMed and Web of Science databases for relevant studies up to January 2024. Additionally, we reviewed the reference lists of related studies to identify any potentially eligible clinical trials. The search strategy is outlined in Table 1.

The inclusion criteria included the following: (1) Participants: Adults (age ≥18) diagnosed with TTH according to International Headache Society criteria; (2) Intervention: Acupuncture therapy alone, without additional treatments; (3) Control: Comparisons to sham acupuncture, placebo, herbs or other control conditions (e.g., waiting list, usual care, no treatment); (4) Outcomes: Responder rate (defined as a ≥50% reduction in TTH frequency), TTH frequency, pain intensity, headache duration, medication consumption and related adverse events; (5) Article Type: Clinical trials, including randomized controlled trials (RCTs), crossover RCTs, etc., published in English. However, the following studies were excluded: (1) Nonclinical studies (e.g., animal experiments, reviews, protocols, case reports, letters, comments); (2) Duplicates and studies with incomplete data; (3) Studies focusing on treatments other than acupuncture (e.g., dry needling, moxibustion); (4) Studies not primarily addressing TTH (e.g., migraine, uncertain diagnosis).

We retrieved a total of 793 articles from PubMed, Web of Science and related reference lists. After removing duplicates, 367 studies were included for assessment. Their titles and abstracts were screened, leading to the exclusion of 320 studies that were either not clinical studies or unrelated to acupuncture. A full-text review resulted in the exclusion of 35 additional studies, and the study selection chart is shown in Fig. 1.

Fig. 1.Selection procedures.

3. Results

A total of 12 English-language clinical studies involving 659 participants who received acupuncture, electroacupuncture or laser acupuncture were found eligible. Among these studies, 11 were randomized controlled trials (RCTs), and one was a crossover RCT [18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29]. Of the 12 studies, 6 focused on chronic TTH [18, 20, 21, 23, 25, 28], while the remaining 6 concentrated on mixed TTH [19, 22, 24, 26, 27, 29].

Regarding the selection of acupoints, there was considerable variation among the 12 studies. Chassot et al. [20] did not specify the names of the acupoints used despite employing acupuncture therapy. Tavola et al. [29] provided only approximate descriptions of the acupoints’ locations, such as on the head, hands or feet. Interestingly, many studies incorporated the principles of TCM differentiation by tailoring acupoint selection to each participant’s individual physical condition. For instance, Schiller et al. [19] and Endres et al. [22] categorized TTH based on TCM meridian theory, including Yangming, Taiyang, Shaoyang, and Jueyin meridians. Additionally, three studies used TCM diagnostic methods to identify specific syndromes and then selected acupoints based on these diagnoses [22, 24, 26]. In contrast, two studies provided only general descriptions of the acupoints used [23, 27].

Acupuncture was employed in eight studies [18, 19, 22, 23, 24, 27, 28, 29], electroacupuncture (EA) in three studies [20, 21, 26], and laser acupuncture (LA) in one study [25]. With the exception of White et al. [28], which did not specify the needle retention time, each acupuncture session generally lasted between 20 and 30 minutes and was administered over a period of 5 to 12 weeks. In most studies, the sessions were repeated for 6 to 8 weeks, with treatments taking place once or twice per week.

The results from 11 studies, excluding White et al. [28], demonstrate that acupuncture was effective for treating TTH without causing serious adverse effects. In addition, acupuncture was shown to improve the response rate and quality of life, reduce pain intensity as measured by visual analog scale (VAS) scores, and decrease pain duration. Follow-up assessments in most studies also indicated a sustained beneficial effect of acupuncture on TTH. Additionally, the study by Chassot et al. [20] reported that electroacupuncture not only reduced VAS scores and the need for analgesics in TTH participants but also increased serum levels of brain-derived neurotrophic factor (BDNF).

4. Discussion

According to a Cochrane systematic review, available evidence suggests that acupuncture is effective for treating frequent episodic or chronic TTH [30]. The European Federation of Neurological Societies guidelines also recognize acupuncture as a potentially important option for patients with frequent TTH [31]. However, previous meta-analyses have primarily demonstrated the efficacy of acupuncture for TTH without providing detailed explanations of its mechanisms.

Acupuncture, derived from TCM theory, is a complex, non-pharmacological intervention involving multiple interacting components [32]. Table 2 presents the results of current acupoint selection for TTH in modern clinical trials, reflecting the insights of ancient TCM practitioners. In TTH treatment, acupuncture prescriptions may vary due to individual differences among patients. Practitioners must possess a solid foundation in TCM and tailor treatment based on the patient’s specific symptoms, which accounts for the variability in mandatory and optional acupoints observed across the 12 studies listed in Table 2.

Chinese experts have noted that the efficacy of acupuncture for TTH is influenced by factors such as the selection of acupoints, frequency of sessions, duration of needle retention, and type of acupuncture used [33]. Furthermore, the methods for selecting acupoints are complex and require further exploration. These factors and their potential mechanisms warrant additional discussion to enhance our understanding of acupuncture’s role in treating TTH.

4.2 Acupoint selection of corresponding meridian distal to the focus

Distal acupoint selection involves choosing acupoints located away from the primary lesion, reflecting the meridian theory of TCM [38]. As shown in Table 2, among the mandatory acupoints, Taichong (LR 3) and Xingjian (LR 2) are located on the foot and correspond to the foot-Shaoyin liver meridian, while Hegu (LI 4) is located on the hand and corresponds to the hand-Yangming large intestine meridian. According to TCM meridian theory, the pathways of both the foot-Jueyin liver meridian and the hand-Yangming large intestine meridian extend through the head. Both Schiller et al. [19] and Endres et al. [22] utilized TCM meridian theory in their selection of optional acupoints. They aligned the specific headache locations with the corresponding meridian pathways in TCM, categorizing them into Yangming meridian headache, Shaoyang meridian headache, Taiyang headache and Jueyin meridian headache. Acupoints corresponding to these meridians were selected for treatment. In practice, distal acupoints are often used in conjunction with local acupoints, guided by meridian theory (Fig. 2).

Fig. 2.Local Acupoint Selection and Distal Acupoint Selection Based on Meridian Theory. Note: The meridian theory of TCM categorizes headaches into Taiyang meridian, Shaoyang meridian, Yangming meridian, and Jueyin meridian headaches. The four red areas represent the regions covered by the corresponding meridians. (Created with Biorender.com).

5. Limitation

Although this review aimed to explore the role of acupuncture in treating TTH from the perspective of TCM and related mechanisms, several limitations must be acknowledged. First, the study is constrained by a small sample size and overall low quality of evidence, which may affect the reliability of the conclusions. Second, there is significant variability in acupoint selection due to differing diagnostic approaches among studies. This lack of consensus on effective acupoints complicates efforts to determine the most beneficial acupoints for TTH treatment. Third, there was a lack of research examining the quantitative effects of acupuncture sessions, the duration of needle retention, and the comparative efficacy of different types of acupuncture. Fourth, there is also a lack of large-sample, multicenter, high-quality clinical studies, leading to generally low methodological and evidence quality. Fifth, the absence of standardized guidelines for acupuncture treatment of TTH further complicates clinical practice. Lastly, acupuncture for TTH remains relatively understudied in terms of its mechanisms, which necessitates further investigation in future research.

6. Conclusion

This review represents the first attempt to analyze the therapeutic role of acupuncture in treating TTH from both TCM perspectives and potential underlying mechanisms. It provides a foundation for future research and offers practical insights for clinicians utilizing acupuncture to manage TTH. Based on the current evidence, a preliminary therapeutic regimen is suggested: First, acupuncturists should select acupoints based on both local and distal sites, guided by TCM syndrome differentiation and the individual characteristics of each patient. Second, the acupuncture treatment course should be extended for no less than four weeks to ensure efficacy. Third, each acupuncture session should last at least 20 minutes, with a recommended duration of 30 minutes to optimize therapeutic outcomes.

7. Key findings

Based on current literature, patients with TTH may benefit from acupuncture therapy. Key factors contributing to effective treatment include the precise selection of acupoints, the duration of needle retention, the type of acupuncture used, and the overall length of the treatment course. These elements are essential for optimizing therapeutic outcomes in TTH management.

Availability of data and materials

The data are contained within this article.

Author contributions

HW, HYC and DCL—took responsibility for the accuracy of the data acquisition and its integrity. HW, HYC and AMW—prepared the initial manuscript draft, revised the article. JWZ and XPS—contributed to the conception and design. CH and JFH—contributed to data interpretation and figures. All authors read and approved the final manuscript.

Ethics approval and consent to participate

Not applicable.

Acknowledgment

The authors would like to thank Biorender.com for its providing material for Fig. 2.

Funding

This work was financed by the State Administration of traditional Chinese medicine high-level key discipline construction project (No. zyyzdxk-2023238).

Conflict of interest

The authors declare no conflict of interest.