Research
tDCS is backed by decades of clinical trials and research.
Halo uses gentle transcranial direct current stimulation (tDCS) to support key brain regions involved in mood, focus, and sleep regulation.
tDCS has been studied for more than two decades and is supported by over 100 peer-reviewed publications demonstrating its safety and its role in enhancing cognitive and emotional performance in healthy adults.
Studies - Mood
Study: Austin et al., 2016 (Front Psychol)
Design: Sham-controlled repeated experiments
Population Type: Healthy
N (participants): 30
Conclusions: Psychological distress (POMS) reduced vs sham
Study: Ironside et al., 2016 (Biol Psychiatry)
Design: Parallel-group RCT
Population Type: Healthy
N (participants): 60
Conclusions: Healthy adults paid less attention to threat signals after one real session (F3→F4) compared with sham; suggests reduced threat vigilance.
Study: Boggio et al., 2008 (Neuropsychologia)
Design: Randomized, counterbalanced
Population Type: Healthy
N (participants): 20
Conclusions: While viewing images of others
in pain, people rated the images as less unpleasant during
left-prefrontal stimulation versus sham—affective/emotion effect (not cognitive focus).
Study: Sanchez-Lopez et al., 2018 (Cogn Affect Behav Neurosci)
Design: Between-subjects RCT
Population Type: Healthy
N (participants): 54
Conclusions: Attentional disengagement
from emotional faces; Improved vs sham
Study: Woodham et al., 2025 (Nat Med.)
Design: Multisite double- blind RCT
Population Type: Clinical
N (participants): 173
Conclusions: HDRS/MADRS; Improved vs sham
Studies - Sleep
Study: McIntire et al., 2020 (Front Hum Neurosci.)
Design: Double-blind placebo-controlled
Population Type: Healthy
N (participants): 36
Conclusions: Group overall tended to sleep less than the other groups in the days after undergoing acute fatigue, potentially indicating faster recovery.
Study: Zhou et al., 2020 (Sleep Med.)
Design: Parallel RCT, double- blind
Population Type: Clinical
N (participants): 47
Conclusions: PSQI; PSG TST, SE, SOL;
Improved vs sham
Study: Zhou et al., 2024 (BMC Med.)
Design: Multicentre RCT (3-arm)
Population Type: Clinical
N (participants): 51
Conclusions: PSQI where reported; Improved vs baseline; combo > mono
Studies - Focus
Study: Keeser et al., 2011 (NeuroImage)
Design: Sham-controlled crossover with EEG
Population Type: Healthy
N (participants): 20
Conclusions: n-back accuracy/RT; rs-fcMRI;
Improved vs sham; connectivity changes
Study: Vanderhasselt et al., 2013 (PLoS ONE)
Design: Within-subjects RCT
Population Type: Healthy
N (participants): 25
Conclusions: Cognitive control for emotional stimuli; Improved vs sham
Study: Metzuyanim-Gorlick
& Mashal, 2016 (Exp Brain Res)
Design: Within-subjects, sham-controlled
Population Type: Healthy
N (participants): 20
Conclusions: Response inhibition (Hayling); Improved vs sham
Study: Bashir et al., 2019 (Physiol Rep.)
Design: Parallel-group RCT (online assessment)
Population Type: Healthy
N (participants): 36
Conclusions: Pattern recognition, stop- signal, RT; Improved vs sham on select measures
Study: Alix-Fages et al., 2023 (BMC
Neurosci.)
Design: Randomized double- blind RCT (hypoxia)
Population Type: Healthy
N (participants): 14
Conclusions: Time to exhaustion; RPE; EMG; CRT; Improved vs sham
Study: Mahesan et al., 2023 (Sci Rep.)
Design: Single-blind crossover
Population Type: Healthy
N (participants): 34
Conclusions: Task shielding (dual-task interference); Improved vs sham
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