Phototherapy for Anxiety Relief

• Can light therapy help with anxiety?
• What is photobiomodulation and does it work for anxiety?

By Dr. Douglas Cowan, Psy.D., MFT

The human body has been responding to light since long before we had words for it.

Sunlight regulates our sleep-wake cycles through circadian rhythms coordinated by the pineal gland. It triggers vitamin D production in the skin, which affects mood, immune function, and brain health. Seasonal changes in light availability shift the neurochemistry of a significant percentage of the population toward depression and anxiety. We have known for decades that light is not just something we see — it is something our biology actively uses.

What is newer is the understanding that specific wavelengths of light can be used as a targeted therapeutic tool — a field called photobiomodulation. And within that field, there is growing research on what light-based therapies can do for anxiety and nervous system dysregulation.

This is worth understanding. Not because phototherapy is a replacement for established anxiety treatments, but because it represents a genuinely different mechanism of action — one that works at the cellular and neurochemical level in ways that complement other approaches.

What’s Happening in the Brain

Anxiety, at its biological roots, involves an overactivated sympathetic nervous system — the branch of the autonomic nervous system responsible for the fight-or-flight stress response. Cortisol stays elevated. The amygdala remains hyperreactive. The body stays in a state of chronic preparation for threat, even when no threat is present.

One of the key physiological markers of a regulated nervous system is heart rate variability (HRV) — the natural variation in the time between heartbeats. A high HRV indicates that the autonomic nervous system is flexible and responsive, able to shift between sympathetic and parasympathetic modes appropriately. Chronic anxiety is associated with reduced HRV — a nervous system that is stuck in sympathetic overdrive and unable to shift fluidly into rest-and-restore mode.

Photobiomodulation works by directing specific wavelengths of light — typically in the red and near-infrared spectrum — into biological tissue. These wavelengths penetrate skin and reach the underlying structures, where they interact with photoreceptors in the mitochondria (the energy-producing centers of cells) and trigger a cascade of biological responses. The mitochondria produce more ATP (cellular energy), cellular signaling improves, inflammation decreases, and tissue repair is supported.

When applied near or over specific acupuncture points or energetically active areas of the body, phototherapy appears to influence the nervous system’s signaling pathways — affecting peptide production, cellular communication, and autonomic regulation in ways that promote calm rather than arousal.

Research has documented measurable effects on relevant biological markers: reductions in cortisol (the primary stress hormone), improvements in HRV (indicating better autonomic regulation), and shifts in neurochemical activity associated with mood and stress resilience.

Now You Understand Why

The reason phototherapy is worth considering as a tool for anxiety is that anxiety is a whole-body phenomenon, not just a brain phenomenon — and whole-body interventions can reach it at levels that purely cognitive approaches cannot.

When the body’s cells are running efficiently, producing adequate energy, and communicating well, the nervous system has a better physiological foundation for regulation. When cellular function is compromised by chronic stress, inflammation, or oxidative damage — all of which are associated with prolonged anxiety — the nervous system struggles to find its baseline.

Think of it this way. Anxiety is partly a downstream consequence of a stressed and depleted system. Approaches that address the upstream cellular environment — reducing inflammation, improving cellular energy production, supporting the neurochemical systems that regulate mood — create better conditions for the nervous system to regulate itself.

Light, in the right wavelengths and delivered appropriately, can do some of that upstream work.

The circadian dimension matters too. Many people with anxiety have disrupted sleep — and disrupted sleep, in turn, worsens anxiety. The pineal gland and its melatonin production, which governs the sleep-wake cycle, are directly regulated by light exposure. Evening light exposure at the wrong wavelengths suppresses melatonin and disrupts sleep quality. Appropriately managed light exposure — getting adequate morning light, reducing blue-light exposure in the evening — supports the circadian rhythm that underlies sleep quality and emotional resilience.

What Wisdom Looks Like Here

Phototherapy for anxiety is a category, not a single tool. Different phototherapy approaches work through different mechanisms.

Bright light therapy — the most established form — is the use of a full-spectrum light box at specific times of day. Its evidence base is strongest for Seasonal Affective Disorder (the depression and anxiety that emerges in low-light seasons), though research also shows benefits for non-seasonal depression and mood regulation. A 2023 review found bright light therapy effective not only for seasonal presentations but as an adjunct for non-seasonal depression and anxiety, with a favorable safety profile. The standard protocol is twenty to thirty minutes of bright light exposure (10,000 lux) in the morning, within an hour of waking.

Photobiomodulation with red and near-infrared light is a newer and more targeted approach. Devices ranging from panel lights to handheld devices to wearable patches can deliver specific wavelengths into tissue. Research is ongoing, but published studies show benefits for brain function, inflammation reduction, mood, and stress markers. A 2024 study in Photobiomodulation, Photomedicine, and Laser Surgery found significant improvements in anxiety, depression, and sleep quality in participants using near-infrared photobiomodulation.

Phototherapy patches — wearable devices that use specific materials to reflect particular wavelengths of the body’s own infrared light — represent an emerging subcategory. The theory is that these patches redirect the body’s own radiated heat toward specific biological targets, stimulating peptide production and cellular signaling without introducing anything into the body. Research into this approach is still developing. Some studies have shown reductions in cortisol and improvements in HRV with certain patch formulations. The products section of this site has detailed information on specific phototherapy patch options and what the available research shows for each.

What To Do Starting Today

• Start with morning light. This is free, requires no device, and has the strongest evidence base. Get outside within an hour of waking and spend twenty to thirty minutes in natural daylight — even on overcast days, outdoor light is far brighter than indoor light. This single practice supports circadian rhythm, cortisol regulation, serotonin production, and sleep quality. It is not a small thing. Many people with anxiety are chronically under-exposed to morning light.

• Manage evening light deliberately. Blue-spectrum light from screens and overhead lighting in the hours before bed suppresses melatonin and disrupts sleep quality. Use warm, dim lighting in the two hours before sleep. Consider blue-light blocking glasses in the evening if screen use is unavoidable. Better sleep is one of the most effective anxiety interventions available — and light management is the most accessible path to better sleep for many people.

• Look into bright light therapy if your anxiety has a seasonal pattern or if your sleep is significantly disrupted. A 10,000-lux light box used for twenty to thirty minutes in the morning has a well-established evidence base. It is non-pharmacological, inexpensive relative to medication, and can be done while eating breakfast. For people whose anxiety worsens in fall and winter, this is worth trying before adding medication.

• Explore photobiomodulation with an open but discerning eye. Red and near-infrared light therapy devices are increasingly available and increasingly studied. Look for products that specify their wavelengths (the most studied range is 600–1100 nanometers) and that have at least some published peer-reviewed research behind them. Discuss with a clinician, particularly if you have photosensitivity or are on any medications that increase light sensitivity.

• Recognize where phototherapy fits in a broader plan. Phototherapy — in any form — is a supporting player, not the whole team. It works best alongside adequate sleep, regular movement, good nutrition, and, where needed, psychological support. It is a tool for improving the biological conditions under which the nervous system operates. That is genuinely useful — but it is not a standalone solution.

Light has been shaping human biology since the beginning. The science of using it deliberately and therapeutically is young but moving fast. What the research already supports is that managing your relationship with light — getting the right light at the right time, avoiding the wrong light at the wrong time, and exploring targeted light-based therapies with appropriate guidance — is one of the more accessible ways to support a nervous system that has been running too hot for too long.

The body already knows how to use light. We’re just learning to work with that knowledge more intentionally.

References

1. Terman, M., & Terman, J. S. (2005). Light therapy for seasonal and nonseasonal depression: Efficacy, protocol, safety, and side effects. CNS Spectrums, 10(8), 647–663.
2. Hamblin, M. R. (2016). Shining light on the head: Photobiomodulation for brain disorders. BBA Clinical, 6, 113–124.
3. Salehpour, F., et al. (2019). Brain photobiomodulation therapy: A narrative review. Molecular Neurobiology, 56(4), 2778–2800.
4. Cassano, P., et al. (2021). Transcranial photobiomodulation for anxiety and mood disorders. Photobiomodulation, Photomedicine, and Laser Surgery, 39(10), 681–692.
5. Koo, T. K., & Nussbaum, E. L. (2024). Red and near-infrared photobiomodulation for anxiety, depression, and sleep: A prospective study. Photobiomodulation, Photomedicine, and Laser Surgery, 42(3), 201–211.
6. Golden, R. N., et al. (2005). The efficacy of light therapy in the treatment of mood disorders: A review and meta-analysis. American Journal of Psychiatry, 162(4), 656–662.
7. Wehr, T. A., & Rosenthal, N. E. (1989). Seasonality and affective illness. American Journal of Psychiatry, 146(7), 829–839.