To evaluate the effect of transcranial direct current stimulation (tDCS) on body weight loss in adults with obesity.

Obesity is a multifactorial disease with limited efficacy from traditional treatments. tDCS can modulate activity in brain regions implicated in appetite control, such as the dorsolateral prefrontal cortex (DLPFC). This updated meta-analysis assesses the effect of tDCS on anthropometric measurements in obese adults.

We conducted a systematic review and meta-analysis, searching four databases (PubMed, Scopus, Embase and Web of Science) through September 2025. Inclusion criteria were randomized controlled trials (RCTs) comparing active tDCS versus control (inactive stimulation or standard care) in adults (≥18 years) with obesity (BMI ≥30 kg/m²). We pre-specified follow-up windows for synthesis: ≤1 month, 1-3 months, and 3-6 months. The primary outcome was the mean difference (MD) in body weight change from baseline, pooled using a random-effects model. PROSPERO ID: CRD420251157581.

Of the seven included RCTs reporting body weight, six studies contributed data to the meta-analysis after stratification by follow-up window, comprising 167 participants (tDCS n=81; control n=86). No eligible studies reported outcomes within the mid-term window (1-3 months). In the short-term (≤1 month; 4 trials; n=107), the pooled MD in change from baseline favored active tDCS but was not statistically significant (MD -1.21 kg, 95% CI -3.12 to 0.70; I²=0%). In the long-term (3-6 months; 2 trials; n=60), the pooled effect was highly imprecise (MD 3.12 kg, 95% CI -13.85 to 20.08; I²=0%). Overall, no statistically significant between-group difference was observed across available time windows.

Active tDCS does not demonstrate a consistent advantage over sham for weight loss in adults with obesity, although tolerability is generally good. These findings should be interpreted cautiously and support the need for longer, larger trials with standardized weight outcomes, transparent reporting of co-interventions, and exploration of alternative stimulation targets beyond the DLPFC.