Skip to main content
Evidence-Based Supplement Research
Evidence-Based Supplement Research
Pillser
Search
Sign UpLog In

Effects of Combined Transcranial Direct Current Stimulation and Oral Capsaicinoids on Swallowing Function: A Randomized Controlled Trial.

  • 2026-05-05
  • Journal of oral rehabilitation 53(8)
    • Ivy Cheng
    • Sonja Suntrup-Krüger

Study Design

Type
Randomized Controlled Trial (RCT)
Population
21 healthy individuals
Methods
Randomized crossover trial, two conditions: anodal tDCS + oral capsaicinoids vs sham tDCS + oral capsaicinoids, 1 week apart, 1 mA for 20 min (anodal) or 30 s (sham), 15-min break, then 150 mL of 10 μM capsaicinoid solution, TWST assessment
Funding
Unclear

Background

The swallowing biomechanics may be modulated by cortical stimulation through transcranial direct current stimulation (tDCS) or sensory stimulation through oral capsaicinoids. However, the effects of combining these techniques remain relatively unexplored.

Objective

This pilot study investigated the effects of tDCS combined with oral capsaicinoids on swallowing function.

Methods

Twenty-one healthy individuals (mean age = 25.8 ± 9.9 years; 7 males, 14 females) received two experimental conditions: (1) anodal tDCS and oral capsaicinoids, and (2) sham tDCS and oral capsaicinoids. The experimental conditions were randomized in order and conducted at least 1 week apart. Anodal and sham tDCS were applied over the right pharyngeal motor cortex at 1 mA for 20 min and 30 s respectively. A 15-min break was given after tDCS, after which participants drank 150 mL of 10 μM capsaicinoid-containing solution. Swallowing function was assessed using the timed water swallow test (TWST) before, immediately after and 15 min after each experimental condition.

Results

The baseline volume per swallow, duration per swallow and swallowing capacity, as assessed by TWST, were comparable between the two conditions. Combined anodal tDCS and oral capsaicinoids significantly increased the volume per swallow compared with combined sham tDCS and oral capsaicinoids (p = 0.003). There were no significant effects of intervention on duration per swallow or swallowing capacity between the two conditions.

Conclusions

We found that combined anodal tDCS and oral capsaicinoids increased the volume per swallow, suggesting potential changes in swallowing biomechanics. The findings imply that cortical stimulation may enhance the effects of peripheral sensory stimulation on the swallowing system.

Research Insights

  • Chili Pepper→Improved Swallowing Capacity

    There were no significant effects of intervention on duration per swallow or swallowing capacity between the two conditions.

    Effect
    Neutral
    Effect size
    Small
    Dose
    10 μM capsaicinoid-containing solution, 150 mL
  • Chili Pepper→Increased Swallow Volume

    Combined anodal tDCS and oral capsaicinoids significantly increased the volume per swallow compared with combined sham tDCS and oral capsaicinoids (p = 0.003).

    Effect
    Beneficial
    Effect size
    Small
    Dose
    10 μM capsaicinoid solution (150 mL)
  • Chili Pepper→Increased Swallowing Capacity

    There were no significant effects of intervention on duration per swallow or swallowing capacity between the two conditions.

    Effect
    Neutral
    Effect size
    Small
    Dose
    10 μM capsaicinoid solution (150 mL)
  • Chili Pepper→Reduced Swallow Duration

    There were no significant effects of intervention on duration per swallow or swallowing capacity between the two conditions.

    Effect
    Neutral
    Effect size
    Small
    Dose
    10 μM capsaicinoid solution (150 mL)
Back to top