Red Light Therapy & Mood: What the Research Really Shows
- Sam Morley
- Dec 10
- 5 min read
"It is during our darkest moments that we must focus to see the light." – Aristotle
In a modern day “tech-filled” world surrounded by artificial light – from early morning alarm clocks and blue light during late-night scrolling, our bodies seem to be paying the price. Blue light exposure, irregular routines, and indoor lifestyles have disrupted the circadian rhythms our ancestors relied on for physical and mental wellbeing. Light is not always a bad thing, but the wrong light at the wrong time can dysregulate sleep, energy, hormones, and mood. And the right type of light, used intentionally, can do the opposite. Light is one of the most powerful signals to our brain and body.
Why Light Matters for Mental Health:
Mental health is a serious topic that has become a wider topic of conversation over social media, partially to destigmatize the matter and also due to its rising prevalence, especially after the COVID-19 pandemic. However, traditional treatments for MDD (major depressive disorder) have consistently involved both pharmacological interventions as well as psychological therapy, such as cognitive behavioral therapy. Although these are promising interventions, antidepressants come with side effects and remission rates remain at about 50% of cases (Farrokh, 2021).
Over the past few years of research, several types of light-based therapies have become popular for mood, energy, and sleep. The most well-studied is bright white morning light (10,000 lux), typically used with “happy light” boxes which help treat seasonal and non-seasonal depression by aligning the circadian clock. There are also blue-enriched light devices, which are especially powerful for boosting alertness and shifting circadian rhythms (helpful in the morning, but potentially disruptive at night). On the other end of the spectrum is red and near-infrared light (photobiomodulation), used less for circadian shifting and more for cellular energy, inflammation, pain, and emerging mood benefits. Other types of light/therapies include dawn simulations (gradually brightening alarm clocks), blue-blocking night glasses or “night mode” filters to reduce evening light exposure, and UV-based therapies for skin or Vitamin D, though those are not typically used directly for mood. Here, I focus on morning bright light, blue light, and red light therapy as they are the most common, currently researched, and accessible in relation to cardiac health, mood regulation, and depression-related symptoms.
What the Research Shows:
Research continues to show that morning light exposure helps regulate our circadian rhythm, improve our mood, and support better sleep and energy throughout the day. Two majors studies, Lao et al, 2020 (PMID: 32622169) and Bais et al, 2021 (PMID: 34266611) highlight the growing evidence for light therapy as an effective tool to both enhance mood and reduce depression symptoms.
A 2020 meta-analysis published in Journal of Affective Disorders examined 23 randomized control trials (RCTs) and found that light therapy significantly reduced depressive symptoms, especially in non-seasonal depression. The best outcomes were when participants practiced consistent exposure, 20-40 minutes of bright light (around 10,000 lux) daily within the first hour of waking up.
A 2021 review in Frontiers in Psychiatry found that morning light exposure acts as a natural mood regulator, helping synchronize internal biological clocks and improve both mental focus and emotional well-being.
What About Red Light Therapy?:
Red light therapy, also known as Photobiomodulation (PBM) = A medical therapy that uses low-wavelength red (660 nm) and near-infrared (850 nm) light to enhance cellular function. This has emerging evidence in mood and brain health.
How It Works:
PBM uses red (660 nm) and near-infrared light (850 nm) to stimulate mitochondria:
ATP production (cellular energy)
Cerebral blood flow
Reduction in inflammatory cytokines
Neuroprotection
Improved sleep quality
While PBM is not a stand-alone treatment for depression, research suggests it can be a helpful adjunct tool when paired with therapy, medication, and lifestyle interventions, especially when used regularly and in the morning (PMID: 39744683).
Blue Light: A Hidden Mood Disruptor
Blue light plays a very powerful role in regulating our circadian rhythm: the internal 24-hour clock which governs sleep, hormone release, digestion and mood. During the day blue light (from the sun) helps keep us alert and aligned with the natural light/dark cycle. At night, exposure to artificial blue light (from phones, laptops, TVs, LEDs, or indoor lights) sends a misleading “daytime” signal to the brain’s master clock, the suprachiasmatic nucleus (SCN). (PMID: 32066704). This research shows that even very low levels of nighttime light (as little as 3 lux – about the brightness of a dim nightlight), can suppress melatonin production and shift the timing of the circadian rhythm.
The takeaway from this research?
Just like other adjunct therapies, this therapy alone should not be treated as a monotherapeutic approach for depression, however it can be hugely successfully in using it as a consistent treatment modality if used properly. Just as if you were to step outside in the sunlight for your daily dose of Vitamin D on a perfectly summer day, if one were to use this approach every day at the same time in the morning, alongside other treatment modalities, the benefits might be huge.
If you are interested in normalizing your natural circadian rhythm and reducing “blue light” at night but still want to utilize your phone, try this hack:
Open Settings.
Tap Accessibility.
Tap Display & Text Size.
Tap Color Filters.
Turn on Color Filters.
Select Color Tint.
Adjust Intensity and Hue sliders all the way to the right
Once the setting is on, you can alternate between blue light and this red light feature by clicking 3 times on your side button on your phone. I use this at night!
Other Recommend Devices:
“Happy Light” with 10,000 LUX LED Bright white light:
“Red Light Therapy, Dual Chip Clinical Grade LED Device with Near-Infrared Light 660nm 850nm High Power Panel” :
Understandably, you might be confused as to why dietitians are talking to you about LIGHT. It may seem unrelated to nutrition at first glance, but it is actually one of the most powerful environmental factors affecting metabolism, digestion, appetite cues, hormones, stress response, and mood. At SkimWellness, we don’t just look at what you eat. We strip back the layers to how your body is functioning and help drive behavior change tailored for you alone. If you want support building routines that regulate your nervous system, strengthen your circadian rhythm, and make your nutrition habits feel more sustainable, OR if you are interested in learning more about the benefits of possible adjunct therapies, reach out to one of our SkimDietitians for more!
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