The connection between light and mood is well-established — SAD (seasonal affective disorder) lamps have been used for decades. But emerging research is exploring whether red and near-infrared light therapy, applied either systemically or directly to the head, can reduce anxiety and improve general mental wellbeing. The science is early but genuinely interesting.

Mechanisms: How Red Light Might Affect Anxiety

Several pathways could explain mood and anxiety effects of photobiomodulation:

  • Transcranial photobiomodulation — Near-infrared light at 810–850 nm can penetrate through the skull and reach cortical brain tissue, where it stimulates mitochondrial function in neurons
  • Cortisol regulation — Some research shows RLT reduces cortisol (the stress hormone) and modulates the HPA (hypothalamic-pituitary-adrenal) axis response
  • Serotonin and dopamine — Light exposure (including NIR) influences monoamine neurotransmitter systems via photoreceptor pathways
  • Improved sleep quality — Red light doesn't suppress melatonin and may support better sleep, which is foundational to anxiety management
  • Anti-inflammatory effects — Neuroinflammation is increasingly linked to anxiety disorders; reducing systemic inflammation may indirectly support mental health

Transcranial Photobiomodulation Research

This is the most directly relevant area of research. A 2021 pilot study found that transcranial near-infrared light (810 nm) applied to the frontal cortex for 8 weeks produced significant reductions in self-reported anxiety and depression scores in participants with major depressive disorder. A 2023 study at Boston University found that transcranial PBM improved cognitive function and reduced anxiety-related behaviors in subjects with PTSD-like responses.

Researchers at Harvard Medical School (Dr. Michael Hamblin's lab) have been among the leaders investigating transcranial PBM for neurological and psychiatric conditions.

Important Context

The evidence for RLT and anxiety is promising but not yet at the level of established treatments. Don't use RLT as a replacement for evidence-based anxiety treatments (CBT, SSRI/SNRI medication, etc.). It may work well as a complement. Always discuss mental health treatment changes with your healthcare provider.

How People Use Red Light for Mental Wellbeing

Two main approaches are emerging:

  • Transcranial application: Handheld NIR devices held 1–4 inches from the forehead/scalp for 10–15 minutes. Some dedicated transcranial devices use 810 nm specifically. This targets the prefrontal cortex — the brain region most implicated in anxiety regulation.
  • Full-body sessions: General full-body RLT produces systemic anti-inflammatory, cortisol-modulating, and sleep-improving effects that support anxiety management indirectly.