Home›Neurology› Botulinum toxin type A reduces upper-limb tremor severity in patients with essential tremor
Botulinum toxin type A reduces upper-limb tremor severity in patients with essential tremorBotulinum Toxin Type A Reduces Tremor in Upper Limbs
Frontiers in MedicinePublished August 28, 2026DOI ↗Editorial oversight: Dr. Ji-eun Park, MD · Brain, Mind & Pain
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Key Takeaway
Consider botulinum toxin type A for tremor reduction while monitoring for potential muscle weakness and grip strength loss.
This meta-analysis evaluates the efficacy and safety of botulinum toxin type A for managing upper-limb tremor in patients with essential tremor. The analysis included 231 participants and compared botulinum toxin type A against placebo over a 24-week follow-up period. The primary finding was a significant reduction in clinician-rated upper-limb tremor severity (Hedges' g, -0.66; 95% CI, -0.94 to -0.38) compared to placebo.
Secondary outcomes showed that botulinum toxin type A may improve investigator-rated global treatment response (Hedges' g, 0.70; 95% CI, 0.06 to 1.34) and patient-rated global treatment response (Hedges' g, 0.40; 95% CI, 0.14 to 0.67). However, the treatment was associated with a higher incidence of muscular weakness (risk difference, 0.19) and a reduction in maximum grip strength (mean difference, -7.13 kg; 95% CI, -11.42 to -2.85).
The authors note that evidence for muscular weakness, investigator-rated response, patient-rated response, and grip strength is of low-certainty. Furthermore, evidence regarding treatment-related adverse events is very uncertain, and estimates for serious adverse events and discontinuations are too imprecise to exclude clinical harm. Clinicians should weigh the reduction in tremor against the risk of muscle weakness and functional impairment when determining treatment plans.
How this fits prior evidence
This meta-analysis extends the clinical utility of botulinum toxin type A beyond its established role in managing sialorrhea in pediatric and adult neurological disorders. While the previous evidence confirmed that botulinum toxin type A effectively manages sialorrhea, this current finding provides specific evidence for its role in reducing upper-limb tremor severity in essential tremor. It also adds specific data regarding the trade-off between tremor reduction and potential muscular weakness or reduced grip strength.
A meta-analysis of 231 adults with upper-limb essential tremor looked at the effects of botulinum toxin type A. The study found that this treatment significantly reduced tremor severity compared to a placebo over a 24-week period. Both patients and investigators reported that the treatment might improve the overall response to the condition.
However, the study also found that botulinum toxin type A was associated with more frequent muscular weakness and a decrease in maximum grip strength. Because the evidence for these specific side effects and the overall treatment response is of low certainty, the results should be viewed with caution.
Doctors must weigh the benefits of reduced tremors against the risks of muscle weakness and functional changes. Because the data on safety and adverse events are currently very uncertain, patients should discuss these specific trade-offs with their healthcare provider to decide if the treatment is right for them.
What this means for you:
Botulinum toxin type A reduces tremor severity but may cause muscle weakness and lower grip strength.
Common questions
Does botulinum toxin type A reduce tremor severity?
Yes, the study found that botulinum toxin type A significantly reduced clinician-rated upper-limb tremor severity compared to a placebo over 24 weeks. This finding was supported by moderate-certainty evidence, making it a clear finding for managing the physical symptoms of essential tremor.
Are there side effects to this treatment?
The treatment was associated with more frequent muscular weakness and a reduction in maximum grip strength. However, the evidence regarding these specific side effects is currently of low certainty. Additionally, evidence regarding other treatment-related adverse events is currently very uncertain.
How do patients feel about the treatment?
Patient-rated global treatment response may improve with botulinum toxin type A. However, the evidence for this specific improvement is of low certainty. You should talk to your doctor to understand how these results might apply to your specific situation.
BackgroundBotulinum toxin type A (BoNT-A) is used as a targeted treatment for upper-limb essential tremor, but uncertainty remains regarding the magnitude and certainty of its benefits and harms. We evaluated the efficacy and safety of BoNT-A compared with placebo in adults with upper-limb essential tremor.MethodsWe systematically searched bibliographic databases, trial registries, and eligible grey-literature sources from inception to July 20, 2026. We included randomized placebo-controlled trials of BoNT-A in adults with upper-limb essential tremor. Primary outcomes were short-term clinician-rated upper-limb tremor severity and muscular weakness through Week 24. Continuous outcomes were summarized using mean differences or Hedges’ g, and binary safety outcomes using risk differences. Random-effects meta-analyses were performed. Risk of bias was assessed at the result level using the Cochrane Risk of Bias 2 tool, and certainty of evidence was evaluated using GRADE.ResultsThree trials with outcome data from 231 participants contributed to the primary efficacy analysis. BoNT-A reduced short-term clinician-rated upper-limb tremor severity compared with placebo (Hedges’ g, −0.66; 95% CI, −0.94 to −0.38; I2 = 0%; moderate-certainty evidence). Muscular weakness was more frequent with BoNT-A (2 trials; 107 participants; risk difference, 0.19; 95% CI, 0.06 to 0.32; I2 = 29%; low-certainty evidence), approximately 190 more participants per 1,000 treated. BoNT-A may improve investigator-rated global treatment response (Hedges’ g, 0.70; 95% CI, 0.06 to 1.34) and patient-rated global treatment response (Hedges’ g, 0.40; 95% CI, 0.14 to 0.67), although certainty was low. Maximum grip strength was reduced (mean difference, −7.13 kg; 95% CI, −11.42 to −2.85; low-certainty evidence). Evidence regarding treatment-related adverse events was very uncertain, whereas estimates for serious adverse events and discontinuation due to adverse events were too imprecise to exclude clinically important benefit or harm.ConclusionBoNT-A probably reduces short-term clinician-rated upper-limb tremor severity but may increase muscular weakness and reduce grip strength. Evidence for global treatment response and less frequent adverse outcomes remains limited or very uncertain. Treatment decisions should balance the expected reduction in tremor against the individualized risk of weakness and functional impairment.
