Efficacy and safety of acupuncture for sarcopenia in older adults: protocol for a systematic review and meta-analysis

Abstract

Introduction

Sarcopenia is a prevalent skeletal muscle disorder among older adults that can significantly diminish their quality of life. While acupuncture is gaining traction as a treatment for various skeletal muscle disorders, there is currently insufficient evidence supporting its efficacy specifically for sarcopenia. Therefore, this systematic review and meta-analysis aims to evaluate the effectiveness and safety of acupuncture interventions for sarcopenia.

Methods and analysis

A comprehensive search will be conducted across eight databases (PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, China Biology Medicine disc, China Science and Technology Journal Database and Wanfang Database) from their inception until December 31, 2025. Additionally, clinical trial registries and other relevant sources will be searched. All randomised controlled trials (RCTs) related to acupuncture treatment for sarcopenia will be included. Data extraction will encompass study details, design, participant demographics, intervention specifics, outcome measures and reported adverse events. The primary outcomes of interest will be muscle strength, muscle mass and physical performance. The risk of bias will be evaluated using the Cochrane Risk of Bias 2.0 (RoB 2) tool. The study selection, data extraction and risk of bias assessment will be independently carried out by two reviewers. A meta-analysis will be performed using RevMan V.5.4 and STATA V.16.0, while descriptive analyses will be conducted as necessary. The certainty of evidence for the outcomes will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

Ethics and dissemination

Ethical approval is not required since the data for this study were obtained from public databases. The findings will be disseminated in a peer-reviewed journal.

PROSPERO registration number

CRD420251067492.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• This systematic review will integrate both subjective and objective outcome measures for evaluating the effects of acupuncture on sarcopenia in older adults.

• We will conduct a comprehensive search across multiple Chinese and English databases.

• The quality of included studies will be evaluated using the revised Cochrane Risk of Bias 2.0 (RoB 2) tool.

• Detailed subgroup analyses based on different forms of acupuncture, treatment regimens and diagnostic criteria for sarcopenia will help us conduct an in-depth assessment of the efficacy.

• The disparity in quality among included original research represents a potential source of heterogeneity, which may impact the reliability of our findings.

Introduction

Sarcopenia is an age-related skeletal muscle disease characterised by progressive, systemic loss of skeletal muscle mass, strength and function.¹ Hormonal changes, ageing, genetics, malnourishment and inactivity are some of the factors that accelerate sarcopenia; the latter two are risk factors that can be changed.² These factors can lead to negative outcomes, including weakness, loss of independence, increased risk of fractures, chronic diseases and premature death.³ The prevalence of sarcopenia is rising annually throughout the world, which seriously affects people’s quality of life and increases social and medical costs.⁴ According to a systematic review comparing the impact of European Working Group on Sarcopenia in Older People (EWGSOP) and EWGSOP2 criteria on the prevalence of sarcopenia, the prevalence rate was 17.7% according to the EWGSOP and 11% according to EWGSOP2, but EWGSOP2 appeared to predict worse adverse outcomes than EWGSOP.⁵ A meta-analysis from China referred to by the diagnostic criteria of EWGSOP, the Asian Working Group for Sarcopenia (AWGS), the International Working Group on Sarcopenia (IWGS) or the Foundation for the National Institutes of Health (FNIH) found that the prevalence of males in China was 12.9%–29.7% and that of females was 11.2%–33.7%.⁶ There are no specific drugs for the treatment of sarcopenia, and resistance exercise and optimisation of nutritional intake remain the mainstay of treatment.⁷ Nonetheless, insufficient adherence to resistance training and individual differences in improving nutritional intake impede its effectiveness. Conventional Western medications (growth hormone, anabolic or androgen steroids, activating II receptor drugs, beta-blockers and angiotensin-converting enzyme inhibitors, etc.) are constrained by issues such as lack of specificity, limited efficacy, a high risk of side effects and insufficient long-term evidence.8,12 Therefore, there is an urgent need to find new safe and effective therapies.

Acupuncture is a traditional Chinese medical practice that has received increasing attention in the prevention and treatment of various diseases in recent years.^{13 14} Studies have shown that acupuncture can improve the state of low inflammation, regulate hormone levels and affect autophagy and apoptosis to achieve the effect of treating or preventing sarcopenia.15,17 A clinical study found that, based on conventional treatment, warm acupuncture can increase skeletal muscle mass, enhance muscle strength, improve muscle function and improve the quality of life and self-care ability of patients with sarcopenia.¹⁸ Derived from routine acupuncture, wei three-needle therapy is effective in increasing walking speed, muscle strength and balance in patients with sarcopenia, while at the same time regulating the patient’s symptoms of weakness.¹⁹ Electroacupuncture continuously stimulates local acupoints and muscles with different frequencies of biological current, which may promote the recovery of muscle function and the regeneration of muscle tissues, thereby improving the living ability of patients.²⁰ Therefore, acupuncture has a certain potential in the treatment of sarcopenia.

However, there are few RCTs of acupuncture in the treatment of sarcopenia; the clinical outcomes are different, and the quality of evidence is different. There is no consensus on the efficacy of acupuncture in the treatment of sarcopenia. This systematic review and meta-analysis will evaluate the effectiveness and safety of acupuncture plus conventional treatment versus conventional treatment alone for sarcopenia in older adults, providing clinical evidence across various outcomes.

Methods

The primary objective of the protocol is to synthesise current evidence on the effects of acupuncture techniques on muscle mass, muscle strength and functional outcomes, to promote informed clinical practice and to guide future research. The protocol is compliant with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Protocols guidelines and was registered with the International Prospective Registry of Systematic Reviews (PROSPERO) database on 6 June 2025 (registration number: CRD420251067492).²¹

Inclusion criteria

Participants

Studies will include adult patients aged 60 years or older diagnosed with sarcopenia, as confirmed by standardised criteria such as AWGS and EWGSOP2.^{22 23} Diagnosis must involve objective measures—such as low muscle mass assessed via dual-energy X-ray absorptiometry (DEXA), bioelectrical impedance analysis (BIA) or magnetic resonance imaging (MRI)—and reduced muscle strength or performance. The specific diagnostic criteria are shown in table 1. No restrictions will be placed on gender, ethnicity or disease duration.

Table 1. Sarcopenia definitions and proposed cut-offs.

Professional group	Sarcopenia definition and proposed cut-offs
AWGS (2019)22	Definition	Low muscle mass plus low muscle strength and/or low physical performance
	Cut-offs	Handgrip strength <28 kg for males, <18 kg for females
		Gait speed <1.0 m/s
		Chair stand >12 s for five rises
		Short Physical Performance Battery ≤9 point score
		Calf circumference <34 cm for males, <33 cm for females
		SARC-F ≥4 scores, or SARC-CalF ≥11 scores
		Height adjusted muscle mass <7.0 kg/m2 for males, <5.4 kg/m2 for females by using dual-energy X-ray absorptiometry
		Height-adjusted muscle mass <7.0 kg/m2 for males, <5.7 kg/m2 for females by using bioimpedance
EWGSOP2 (2019)23	Definition	Low muscle strength (probable) Low muscle quantity or quality (confirmed) Low physical performance (severe)
	Cut-offs	Grip strength <27 kg for males, <16 kg for females
		Chair stand >15 s for five rises
		ASM <20 kg for males, <15 kg for females
		ASM/height2 <7.0 kg/m2 for males, <5.5 kg/m2 for females
		Gait speed ≤0.8 m/s
		Short Physical Performance Battery ≤8 point score
		Timed up and go ≥20 s
		400 m walk test non-completion or ≥6 min for completion

ASM, appendicular skeletal muscle mass.

Interventions

The experimental group will receive acupuncture combined with conventional treatment. Acupuncture included traditional acupuncture, fire-needle therapy and electroacupuncture, and conventional treatment will be consistent with the control group.

Comparisons

The control group will receive conventional treatment only, or will receive sham acupuncture combined with conventional treatment. Conventional treatment for sarcopenia includes conventional Western medications, exercise, nutritional support and lifestyle changes.

Outcomes

The primary outcomes that align with the core diagnostic criteria of sarcopenia are as follows:

1. Muscle strength: handgrip strength.

2. Muscle mass: appendicular skeletal muscle mass (ASM), measured using MRI, DEXA or BIA.

3. Physical performance: 6-metre walk test, 5-time chair stand test and Short Physical Performance Battery.

A positive result in any primary outcome will be considered evidence of acupuncture’s effectiveness, as each reflects a distinct, clinically relevant domain of sarcopenia.

The other outcomes, which provide supportive information on overall health status and safety, include:

1. Body composition indices: bone mass and body circumferences (e.g., calf circumference, waist circumference).

2. General health status: EuroQol Five Dimensions Questionnaire Five Levels (EQ-5D-5L).²⁴

3. Nutrition: Mini-Nutritional Assessment (MNA).²⁵

4. Incidence of adverse events: any adverse events during treatment.

Study design

Only randomised controlled trials (RCTs) published in peer-reviewed journals will be eligible for inclusion. Both parallel and crossover designs will be considered if they conform to quality standards and provide extractable data.

Exclusion criteria

Studies will be excluded based on the following criteria:

1. Studies focusing on sarcopenia occurring alongside other diseases such as cancer, cachexia, obesity, haemodialysis or neurological disorders will be excluded.

2. Publications meeting the inclusion criteria but lacking accessible data or results, even after attempts to contact the authors, will be excluded.

3. Unpublished protocols, ongoing trials or studies with incomplete results that are not yet available at the time of review will be excluded.

Literature search strategy

A comprehensive search strategy will be developed for each electronic database, combining MeSH and free-text keywords. Core search terms will include “sarcopenia”, “muscle weakness”, “muscle strength”, “acupuncture”, “acupuncture therapy”, “randomized controlled trial”, etc. For example, the search syntax developed for PubMed is as follows: ((Sarcopenia [MeSH Terms] OR Sarcopenias [Title/Abstract] OR Muscle Weakness [Title/Abstract] OR Muscle Strength [Title/Abstract] OR Muscular Strength [Title/Abstract] OR Grip Strength [Title/Abstract] OR Handgrip Strength [Title/Abstract] OR Dynapenia [Title/Abstract] OR Muscle Atrophy [Title/Abstract]) AND (Acupuncture [MeSH Terms] OR Acupuncture Therapy [Title/Abstract] OR Acupuncture Points [Title/Abstract] OR Electroacupuncture [Title/Abstract] OR Body Acupuncture [Title/Abstract] OR Manual Acupuncture [Title/Abstract] OR Auricular Acupuncture [Title/Abstract]) AND (Randomized Controlled Trial [Title/Abstract] OR Controlled Clinical Trial [Title/Abstract] OR RCT [Title/Abstract] OR Randomly [Title/Abstract])). The specific search strategy is shown in table 2.

Table 2. Search strategy.

Number	Search terms
#1	Sarcopenia
#2	Sarcopenias OR Muscle Weakness OR Muscular Weakness OR Muscle Strength OR Muscular Strength OR Grip Strength OR Handgrip Strength OR Dynapenia OR Muscle Atrophy
#3	#1 OR #2
#4	Acupuncture
#5	Acupuncture Therapy OR Acupuncture Points OR Electroacupuncture OR Body Acupuncture OR Manual Acupuncture OR Auricular Acupuncture
#6	#4 OR #5
#7	Randomized Controlled Trial OR Controlled Clinical Trial OR RCT OR Randomly
#8	#3 AND #6 AND #7

RCT, randomised controlled trial.

The search will span from database inception until December 31, 2025. The following databases will be searched: PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), China Biology Medicine disc (CBM), China Science and Technology Journal Database (VIP) and Wanfang Database. Additionally, clinical trial registries such as ClinicalTrials.gov and the International Clinical Trial Registry Platform (ICTRP) will be searched to identify relevant trial registration numbers. These numbers will then be used to perform a reverse citation search within electronic databases to locate any associated publications, thereby reducing the risk of omission. Reference lists of key reviews and eligible studies will be manually screened to expand coverage. No restrictions on the language of publication will be applied. For non-English language studies, we will use a combination of translation software (e.g., DeepL, Smartcat) along with artificial intelligence (AI)-assisted tools (ChatGPT). Initially, we will use these specialised medical translation resources to obtain a preliminary understanding of the content, followed by a thorough review and refinement by bilingual researchers with expertise in medical terminology to ensure accuracy and contextual relevance.

Study selection process

All retrieved records will be imported into EndNote. Records that are duplicates due to different literature sources or similar literature content will be manually deleted and verified. Two independent reviewers will screen titles and abstracts for eligibility according to the inclusion/exclusion criteria. Potentially eligible articles will be retrieved in full text and assessed independently by both reviewers. Disagreements will be resolved through discussion or consultation with a third reviewer. A PRISMA flow diagram will be used to document the study selection process (figure 1).

Figure 1. Flow diagram of the study selection process. CBM, China Biology Medicine disc; CNKI, China National Knowledge Infrastructure; ICTRP, International Clinical Trial Registry Platform; RCT, randomized controlled trial; VIP, China Science and Technology Journal Database.

Data extraction

A standardised data extraction form will be developed and pilot tested. Extracted data will encompass the following: study details (authors, publication year, journal and geographic location), study design (randomisation method, blinding procedures, sample size, duration, setting), participant demographics (gender, diagnostic criteria for sarcopenia, baseline muscle or functional status), intervention specifics (acupoint selection, needle type, insertion depth, stimulation methods, session duration, frequency and total treatment duration), outcome measures (measurement tools, timing of assessments, results), adverse events (type, frequency, severity related to acupuncture) and other variables (compliance rates and dropouts). All data extraction will be performed independently by two reviewers. Discrepancies will be addressed via discussion or third-party resolution. Corresponding authors will be contacted if clarification or missing data are identified.

Risk of bias assessment

The methodological quality of the included RCTs will be systematically evaluated by two independent reviewers using the Cochrane RoB 2 tool. This comprehensive assessment covers several key domains to ensure a thorough appraisal of each study’s internal validity. First, the randomisation process will be scrutinised, focusing on how the random sequence was generated and whether allocation concealment was adequately implemented to prevent selection bias. Next, the deviations from the intended intervention domain assess whether blinding of personnel and participants was maintained to avoid performance bias and whether any deviations from the prescribed interventions could have influenced outcomes. The missing outcome data domain examines the extent and reasons for losses to follow-up or incomplete data, as well as how these missing data were handled statistically, to evaluate attrition bias. The measurement of outcomes domain evaluates whether outcome assessors were blinded and whether measurement methods were consistent and appropriate, thereby reducing detection bias. Finally, the selective reporting domain reviews whether the study adhered to its pre-registered protocol to identify reporting bias. Each domain is rated as ‘low risk’, ‘some concerns’ or ‘high risk’, providing a nuanced understanding of potential bias sources. An overall bias judgement is then assigned based on the combined domain ratings. Discrepancies between reviewers will be addressed through discussion or by consulting a third reviewer to reach a consensus, ensuring objectivity and reliability of the bias assessment process.

Data synthesis and statistical analysis

To synthesise the data extracted from eligible studies, RevMan V.5.4 and STATA V.16.0 will be employed. Continuous outcomes will be summarised using weighted mean differences (MD) when measurement scales are consistent across studies. If different measurement scales are used, standardized mean differences (SMD) will be calculated to enable comparison. Dichotomous outcomes, such as the incidence of adverse events, will be expressed as risk ratios (RR) with 95% CIs.

Prior to pooling data, heterogeneity among studies will be assessed using the Chi-square test (with a significance threshold set at p-value <0.05) and quantified through the I² statistic. An I² value of 0–25% will be regarded as low heterogeneity, 25–50% as moderate heterogeneity, 50–75% as substantial heterogeneity and above 75% as considerable heterogeneity. When heterogeneity is low (I²<50%), a fixed-effects model will be used; in cases where heterogeneity is moderate or high (I²≥50%), a random-effects model will be adopted to account for variability across studies. If heterogeneity remains high or if the data are too heterogeneous to pool meaningfully, a narrative synthesis will be performed describing the patterns and trends observed in the various studies.

Heterogeneity analysis

Meta-regression analysis

Meta-regression analysis will be employed to investigate the potential sources of heterogeneity across the included studies. This statistical technique enables researchers to assess how certain study-level characteristics may influence the overall effect of acupuncture interventions on sarcopenia outcomes. Key variables such as gender, duration of intervention and baseline characteristics will be considered covariates in this analysis. For instance, gender differences could lead to variations in treatment efficacy, as hormonal and metabolic factors may influence muscle health differently in men and women. By systematically examining these variables, meta-regression analysis will help identify specific factors that contribute to the effectiveness of acupuncture, thereby guiding future research and clinical practice.

Subgroup analysis

Subgroup analyses will be conducted based on predefined characteristics to further explore the effectiveness of acupuncture interventions among different populations. Clinical heterogeneities (diagnostic criteria, acupuncture type, sarcopenia severity, primary disease, control treatment) will be addressed through subgroup analyses. For diagnostic criteria (AWGS and EWGSOP2), we will classify studies and evaluate the impact of these definitions on indicators of muscle mass, strength and physical function performance. Acupuncture-type subgroups will include traditional acupuncture, fire-needle therapy and electroacupuncture. Sarcopenia severity will also be analysed in subgroups. We will conduct separate analyses for different primary diseases to determine disease-specific treatment effects. Control treatment regimen subgroups (exercise, nutritional support, pharmacological interventions) will assess the impact of control interventions. If subgroups lack sufficient studies, we will combine categories or perform descriptive analyses.

Leave-one-out sensitivity analysis

To assess the robustness of our findings, sensitivity analyses will be performed using a leave-one-out approach. This method involves systematically excluding one study at a time from the meta-analysis to evaluate its impact on the overall effect size. The purpose is to determine whether any single study disproportionately influences the overall results, which could suggest bias, methodological flaws or heterogeneity sources. If the overall effect size remains consistent despite the exclusion of individual studies, we can be more confident in the validity of our findings. Conversely, if the removal of a particular study leads to significant changes in the effect size, it may indicate that this study has unique characteristics or biases that warrant further investigation. The results of the sensitivity analyses will provide valuable insights into the stability of our conclusions regarding the effectiveness of acupuncture for sarcopenia.

Publication bias

Potential publication bias will be visually examined using funnel plots when ≥10 studies are available for a specific outcome. Asymmetry may indicate bias, which will be statistically tested via Egger’s regression asymmetry test. A p-value <0.05 suggests significant bias. When bias is suspected, the trim-and-fill method will be applied to estimate the number of missing studies and adjust the pooled effect accordingly, providing a more accurate estimate of the true effect size.

Certainty of evidence

The certainty of evidence for the outcomes will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, a widely recognised and robust framework for evaluating the quality of evidence in healthcare research. The GRADE approach systematically examines several critical factors that contribute to the overall quality of evidence.²⁶ Evidence quality assessment encompasses multiple critical factors. RCT studies are generally considered the gold standard, but quality may decline if research is primarily observational.²⁷ Assessing risk of bias involves scrutinising methodological flaws such as selection bias.²⁸ Analysing inconsistencies in results requires examining differences between studies.²⁹ Considering indirectness involves assessing applicability between study subjects and the target population.²⁹ Evaluate imprecision by examining confidence intervals and sample size.³⁰ Assess publication bias by scrutinising selective reporting of positive results.³¹ Ultimately, the certainty of each finding is rated as high, moderate, low or very low, providing reliable evidence for clinical decision-making.²⁶

Discussion

Sarcopenia is a progressive muscular dystrophy with a high prevalence in older adults.³² As the global elderly population increases, the incidence of sarcopenia is expected to rise in tandem.⁴ The pathogenesis of sarcopenia is complex, and exercise and nutritional supplementation appear to be the only two effective strategies for slowing the progression of sarcopenia and improving symptoms. However, these two methods are often faced with the dilemma of poor compliance among older adults, and the effect varies from person to person. Acupuncture is a complementary and alternative medical technology, and its potential therapeutic value has been recognised. Some research results show that acupuncture has a positive impact on the treatment of sarcopenia.^{33 34} Therefore, this systematic review and meta-analysis aims to assess the efficacy and safety of acupuncture interventions for sarcopenia in older adults, which guides future research and clinical practice in the treatment of sarcopenia.

We anticipate that acupuncture therapy may have a positive impact on the treatment of sarcopenia. At the efficacy level, acupuncture is expected to increase skeletal muscle mass and strength and improve gait speed, balance assessments and other physical performance. At the micro level, acupuncture may decrease the release of pro-inflammatory factors, elevate the levels of hormones such as testosterone and insulin-like growth factor and improve the imbalance of autophagy and apoptosis. At the safety level, the incidence of adverse effects occurring during acupuncture treatment, such as localised reactions like pain and bruising, needle sickness and transient weakness, is relatively low. In addition, some studies have reported that the acupuncture intervention programme may not have any significant impact on the study population, but the older adults who received acupuncture intervention expressed subjective improvement, which may be related to the acupoint selection and course of acupuncture.³⁵ Therefore, the differences in acupoint selection, course of treatment, acupuncture methods and other factors are included in the heterogeneity analysis, which can reveal the differential characteristics under different conditions and improve the prediction effect and accuracy.

This systematic evaluation and meta-analysis still has some limitations that may affect the results of the study. First, the inclusion criteria only consider RCTs published in peer-reviewed journals, but the overall quantity and quality of available RCTs for acupuncture and moxibustion treatment of sarcopenia are still limited, and studies with negative or uncertain results are unlikely to be published. Second, the intervention measures included in the research are diverse, and this heterogeneity of treatment methods may lead to differences in results. The possibility of differences in skills and experience of practitioners in acupuncture may further complicate the interpretation of results. In addition, short-term studies may not be able to capture long-term benefits or adverse events. Another limitation is that the results measured in this review cover a wide range of physical and health-related parameters. The differences in measurement tools and evaluation time between different studies may lead to inconsistencies, making the synthesis of results more complex. Finally, although the planned meta-regression and subgroup analysis are valuable, they rely on the availability of sufficient data included in the study. Based on the results of this systematic evaluation and meta-analysis, future research should focus on optimising acupuncture protocols to improve comparability between studies and address heterogeneity associated with technique variability and treatment duration. Larger multicentre RCTs are needed to explore the long-term effects of acupuncture on sarcopenia, with a particular focus on diverse populations to improve generalisability. Exploring the biological mechanisms underlying the effects of acupuncture on muscle tissue could provide deeper insights into its physiologic benefits. In addition, qualitative studies examining patients’ experiences and perceptions of acupuncture in the treatment of sarcopenia could inform clinical practice and improve patient adherence to treatment.