FREQUENTLY ASKED
Questions
What is the difference between neurofeedback and neurostimulation?
Neurofeedback shows you your own physiological data so that you learn, through repetition, to self-regulate. The change happens in you. Neurostimulation delivers a current or signal that alters neural activity directly, with no learning required. Some modern devices combine sensing and stimulation, but that combination is closed-loop stimulation rather than neurofeedback unless the user is shown their signal and trained on it.
Is EEG or PPG better for a brain-health wearable?
Neither is universally better, because they measure different systems. EEG measures cortical electrical activity directly and is more precise for brainwave-specific training. PPG measures blood volume pulse, yielding heart rate variability as a proxy for autonomic state, and is far more comfortable for continuous all-day wear. Choose EEG for session-based training and PPG for passive monitoring.
Is tDCS safe to use every day?
Within established parameters — sessions of 40 minutes or less at currents of 4 mA or less — Bikson et al. (2016) documented no serious adverse events across more than 33,200 sessions. Mild tingling, itching, and transient scalp redness are common. Long-term safety data for extended consecutive daily use in unsupervised consumer settings remains limited, so follow the device's disclosed protocol and avoid products that encourage unlimited daily use.
Do binaural beats actually work, or is it placebo?
The evidence is stronger than the reputation for acute anxiety, where a 2025 meta-analysis found binaural audio outperformed both silence and non-binaural music across randomised perioperative trials. For cognitive enhancement in healthy adults, the picture is mixed, with several well-controlled studies finding no effect on vigilance or measurable cortical entrainment. Outcomes depend heavily on beat frequency, carrier tone, and background masking, so results are real but not uniform.
Are brain-health wearables FDA approved?
Almost none are. Nearly all are sold as consumer wellness products, which are legal to sell without FDA review provided they make no disease claims and which therefore carry no independent verification of their benefit claims. The exception is Flow Neuroscience's FL-100, which received FDA premarket approval on December 8, 2025, for moderate-to-severe major depressive disorder as a prescription home-use device. No device holds FDA approval for focus, attention, or cognitive enhancement.
Who should not use a neurostimulation wearable?
Avoid tDCS and similar electrical stimulation if you have metal implants in or near the head, a cardiac pacemaker or defibrillator, a personal or family history of epilepsy or seizures, active skin conditions at the electrode sites, or if you are pregnant. Consult your prescribing physician first if you take medications that lower the seizure threshold.
Can companies sell my brain data?
Many reserve the right to. A 2024 Neurorights Foundation audit of 30 consumer neurotechnology companies found 96.7% claimed the right to transfer neural data to third parties, with fewer than 20% mentioning encryption. Colorado, California, Montana, and Connecticut have since enacted neural data privacy laws, and UNESCO adopted a non-binding global framework in November 2025. Read any device's privacy policy for three things: transfer rights, whether processing happens on-device, and whether you can export and delete your data.
What should I look for in the best brain wearable?
Seven things: whether it senses, stimulates, or both; whether the sensor matches your actual goal; whether the stimulation protocol discloses current, duration, and electrode placement; whether safety limits are enforced in hardware rather than software; whether the brand publishes evidence that contradicts it; what consumables and subscriptions cost in year two; and whether you will realistically wear it daily. The last one decides outcomes more often than the first six.
Does tDCS improve focus?
Not on its own. The most-cited meta-analyses in the field found that single-session tDCS in rested healthy adults produces no reliable cognitive effect, and that tDCS alone does not reliably improve working memory. Effects appear when stimulation is paired with a concurrent cognitive task, at roughly d ≈ 0.3–0.4, with larger sustained transfer effects for multi-session task-congruent protocols. Treat any guaranteed-focus claim with scepticism, from any brand.