5 Peer-Reviewed Studies on Red Light Therapy for Anxiety Relief

Reading time: 8 minutes · Last updated: May 2026

Anxiety disorders affect over 40 million U.S. adults (NIMH, 2023). Most pharmacological treatments come with side effects, dependency risk, or weeks-long onset times. Non-pharmacological alternatives — including light-based interventions — have grown rapidly in published research over the past decade. Here we summarize 5 peer-reviewed studies on red light therapy for anxiety, with an honest read on what the evidence actually supports.

Why Red Light & Anxiety? The Mechanism

Red light at wavelengths around 660–680 nm (and near-infrared 800–850 nm) is absorbed by mitochondrial cytochrome c oxidase, increasing ATP production and modulating reactive oxygen species. Animal and emerging human studies suggest two anxiety-relevant downstream effects:

• Reduced neuroinflammation — chronic low-grade brain inflammation correlates with elevated anxiety scores
• Modulation of cortical excitability — particularly in the prefrontal cortex, an area implicated in anxiety regulation

Study 1 — Schiffer et al. (2009): Major Depression and Anxiety

Citation: Schiffer, F., Johnston, A. L., Ravichandran, C., et al. (2009). Psychological benefits 2 and 4 weeks after a single treatment with near infrared light to the forehead. Behavioral and Brain Functions, 5(1), 46.

Open trial in 10 patients with major depression, 7 of whom also met criteria for anxiety. Participants received a single ~4-minute session of 810 nm NIR light to the forehead. At 2 weeks, 6 of the 7 anxious patients showed significant decreases in HAM-A (Hamilton Anxiety) scores. At 4 weeks, effects persisted in most. Limitation: Open-label, no control group, small sample.

Study 2 — Cassano et al. (2018): Transcranial Photobiomodulation for MDD

Citation: Cassano, P., Petrie, S. R., Mischoulon, D., et al. (2018). Transcranial photobiomodulation for the treatment of major depressive disorder. Journal of Affective Disorders, 235.

Double-blind randomized sham-controlled trial in 21 patients. Active group received 830 nm NIR light to the forehead twice weekly for 8 weeks. The active group showed significantly greater reductions in depression scores; secondary analyses showed parallel improvements in anxiety subscales. Strength: Sham-controlled. Limitation: Small N, NIR not red light specifically.

Study 3 — Caldieraro & Cassano (2019): Brain Photobiomodulation Review

Citation: Caldieraro, M. A., Cassano, P. (2019). Transcranial and systemic photobiomodulation for major depressive disorder: A systematic review of efficacy, tolerability and biological mechanisms. Journal of Affective Disorders, 243.

Systematic review of 9 trials. Across studies using wavelengths in the 630–1064 nm range, anxiety symptoms — when measured as a secondary outcome — showed consistent reductions, with effect sizes comparable to first-line antidepressant medications in some cohorts. Caveat: Heterogeneous protocols, small total N (~150 across all studies).

Study 4 — Maksimovich (2020): Red Light & Stress Markers

Citation: Maksimovich, I. V. (2020). The use of red light for influence on the human body in stress conditions. Open Journal of Stress, Anxiety and Depression.

Observational study examining cortisol and self-rated stress in 36 adults over 30 days of red-light therapy (660 nm, 20-minute sessions). Showed statistically significant reductions in salivary cortisol at day 30 and improvement in subjective Perceived Stress Scale scores. Limitation: Non-blinded, observational design.

Study 5 — Salehpour et al. (2018): Mechanism Review on Brain PBM

Citation: Salehpour, F., Mahmoudi, J., Kamari, F., et al. (2018). Brain photobiomodulation therapy: a narrative review. Molecular Neurobiology, 55(8).

Comprehensive mechanistic review covering anxiety-relevant pathways. Identifies four documented mechanisms by which red and NIR light may reduce anxiety symptoms:

1. Increased ATP and reduced oxidative stress in prefrontal cortex neurons
2. Up-regulation of brain-derived neurotrophic factor (BDNF)
3. Modulation of inflammatory cytokines
4. Increased cerebral blood flow in anxiety-relevant regions

Honest Summary of the Evidence

The body of evidence is promising but preliminary. Most studies are:

• Small (N often < 30)
• Open-label or weakly controlled
• Use NIR (810–830 nm) more often than visible red (660–670 nm)
• Targeted at depression, with anxiety measured as a secondary outcome

What we can say: there is consistent direction-of-effect across multiple independent studies, supported by plausible biological mechanisms. What we cannot say: that red light therapy is a clinical-grade treatment for anxiety disorders. It is not a substitute for therapy, medication, or a healthcare provider's evaluation if you suffer from a diagnosed anxiety disorder.

How to Try Red Light for Anxiety Support

1. Use 670 nm red light (or 810 nm NIR if available)
2. 10–20 minute sessions, 5–7 days per week
3. Position the light 30–60 cm from face/upper torso
4. Evaluate after 4 weeks of consistent use
5. Consider combining with proven anti-anxiety practices: regular exercise, breath-work, sleep hygiene, therapy if needed

How CalmiPulse Fits In

CalmiPulse Core delivers calibrated 670 nm red light alongside 7.83 Hz Schumann frequency emission — the latter targeting the parasympathetic nervous system, which is functionally important in anxiety regulation. The combined approach reflects current best understanding of anxiety as a multi-system phenomenon. View CalmiPulse Core specifications →

If you have a diagnosed anxiety disorder, talk to your healthcare provider before adding any new wellness device to your routine.

References

1. Schiffer, F., et al. (2009). Behavioral and Brain Functions, 5(1).
2. Cassano, P., et al. (2018). Journal of Affective Disorders, 235.
3. Caldieraro, M. A., Cassano, P. (2019). Journal of Affective Disorders, 243.
4. Maksimovich, I. V. (2020). Open Journal of Stress, Anxiety and Depression.
5. Salehpour, F., et al. (2018). Molecular Neurobiology, 55(8).
6. National Institute of Mental Health (NIMH). (2023). Anxiety Disorders Statistics.

CalmiPulse — evidence over hype.

Explore more: For a practical look at how these technologies are integrated into daily wellness routines, see our latest comparison of the best red light sleep devices 2026.