Phototherapy (bright light therapy) may relieve some symptoms of seasonal depression, a common mood disorder that occurs mainly in winter when natural sunlight is limited. Although more research is needed to know its exact effects, bright light therapy for depression seems promising in several ways. 

Let’s look closer at what bright light therapy is, how it’s thought to work, and the benefits this safe, alternative form of therapy may offer people who live with the winter blues.

What is Light Therapy?

Light therapy involves being exposed to bright light via a commercial light-emitting device. To get the benefits, you position yourself near the light therapy box without staring into it directly.

As the wavelengths of light contact your eyes and skin, they cause physiological, physical, and psychological changes that are thought to reduce some depression symptoms. Light therapy is also believed to affect the circadian rhythm, which is the natural biological clock our bodies run on. According to studies, This form of therapy has been known to cause changes in appetite, sleep patterns, energy levels and mood, and hair and skin health

Exposure to bright light is well-tolerated by most people. Phototherapy is considered a safe, nonpharmacological modality that can be used as a standalone treatment, or in conjunction with other types of therapy for depression and/or antidepressant medications like Prozac (fluoxetine).

According to research, there’s a 1000-plus year history of the use of light to treat conditions like lethargy and melancholia. Further, natural light has been an important consideration when building hospitals for centuries. Decades of animal research have indicated that light has an impact on activity, reproduction, and sleep in animals.  

In the 1980s, scientists discovered that exposure to bright light can suppress melatonin secretion, which indicates that light gives crucial signals to the brain about the time of day, and perhaps the season.

Since then, research has continued exploring the links between light and seasonal affective disorder (SAD) and other depression disorders, including major depressive disorder (MDD) and bipolar disorder. More research is needed before we can fully understand how light can improve wellbeing in those who live with depression and anxiety disorders.

“For individuals who struggle with seasonal affective disorder, a light lamp can help make up for the lack of exposure to natural sunlight during the winter months. These lamps are made to mimic natural sunlight and provide relief from depressive symptoms such as difficulty sleeping and low mood.” – Talkspace therapist Bisma Anwar, LMHC

Talkspace therapist Bisma Anwar, MA, MSc, LMHC

Some exciting modern research is focusing on how light therapy and light boxes can improve other medical conditions including Parkinson’s disease, breast cancer recovery, migraine headaches, and more.

Types of Light Therapy

Scientists are now exploring the different effects of exposure to different colors of light, which all have varying wavelengths. Ultimately, they’re curious about how different lengths of light waves affect human health and function.

The visible light spectrum includes colors that the human eye can detect. They range from violet to red, with violet having the shortest wavelengths (at about 400 nanometers) and red having the longest (at about 700 nm).

Light causes numerous effects in the body beyond just passing through the retinas to allow vision. It also can stimulate: 

  • Production of vitamin D in skin cells
  • Natural internal clocks that control metabolism
  • Production of mitochondrial adenosine triphosphate (ATP)
  • Production of carbon-based molecules like glucose (C6H12O6)

Changes in light can disrupt connections to central clocks throughout the body, possibly causing poor sleep, impaired cognition, and yes, we think depression.

We also now know that we have special light-sensitive cells in our eyes. These aren’t used for vision. They instead send neuronal fibers into higher brain centers that control both emotion and learning. Ultimately, it seems clearer than ever that light isn’t just critical for cognition and learning. It might also be essential for a positive mood.

Red light therapy

Is red light therapy for depression effective? The average 700 nm wavelength of red light is absorbed into cells deeper than blue or green light wavelengths. It penetrates and provides energy to mitochondria, the energy production centers of eukaryotic cells. Red light treatment in turn enhances cellular reproduction and function.

While the precise effects of red light therapy for depression are not yet known, red light wavelengths are associated with healthier skin and hair. Red light also might help treat common comorbid depression symptoms including muscle pain, headache, and insomnia. As exciting as this is, more research is still needed.

Blue light therapy

There is still debate about whether blue light therapy for depression is the best way on how to treat depression. Blue light’s shorter waves (just 450-495 nm) are thought to stimulate the retina, which can then stimulate the hypothalamus. Hypothalamic stimulation increases the production of serotonin, a brain chemical known to regulate appetite and mood. 

The production of melatonin, the hormone that regulates our sleep, is also increased. Blue light therapy for depression may be an effective modality for those who live with SAD symptoms, but again, more research is needed.

Green light therapy

Green light’s 495-570 nm wavelength is known to enhance circulation, collagen production, and other similar effects of red and blue light exposure. While there’s no solid evidence that green light therapy improves depression, it has recently been shown to reduce migraines by up to 60%. Of course, more research is needed here as well. 

Light Therapy Benefits for Depression

It’s clear that the benefits of light therapies specifically for depression require more clinical research to understand. There haven’t been enough large-scale, randomized human trials to make any definitive determinations.

However, exposure to bright light is known to cause certain effects that might be beneficial to people who are dealing with depression. Let’s take a closer look at the pros and cons of light treatment in general.


While phototherapy isn’t a cure for depression or any other mental health condition, it can provide you with certain benefits to help make symptoms more manageable. These can include:

Upregulated energy production

By stimulating ATP production inside skin cells, bright light therapy can help increase overall energy. This can be helpful for depression, which is often marked by feelings of fatigue and low energy.

Migraine treatment

Studies offer promising hope about light therapy and migraine. Research has linked light therapy to reduction in both frequency as well as intensity in those who live with migraine. 

Improved sleep cycle and depression

Routine bright light therapy for depression helps you form stronger associations between waking and non-waking hours. This encourages a more regular sleep cycle, which can help to reduce and manage sleep disorder or other symptoms of depression. Research shows high bluish white light levels in the morning hours might be beneficial for elderly people living with sleep struggles or depression. 

“Light therapy can activate serotonin in the brain and helps regulate melatonin levels needed for sleep. These two hormones are often impacted by lack of sunlight so a light lamp can help make up for that in winter months.”

Talkspace therapist Bisma Anwar, MA, MSc, LMHC

Healthier hair and skin

Exposure to bright light stimulates collagen production in the skin, which combats premature aging symptoms like wrinkles and fine lines. Stimulating collagen production in the scalp can also make your hair more lustrous. Healthier skin and hair can help you to feel better about yourself, which might help decrease depression.

Enhanced mindfulness of emotions

When you develop a routine that includes bright light therapy each morning, you’re training your mind in a positive way. In essence, you might be teaching your brain how to better anticipate and manage some of the symptoms of depression that are most interfering with your life. Being mindful of depression is key to successful symptom management. Some research suggests that light therapy can improve emotion regulation. 

Other benefits of light therapy are that it’s extremely accessible and convenient. You’re able to do it at home. It’s also noninvasive, non-pharmacological, and quite affordable. Treatments are known to be safe for most people. Finally, it’s easy. You can use a light therapy box while eating breakfast, reading a magazine, or even soaking in the bathtub.


There are few adverse effects associated with using light therapy for depression. A small percentage of people have reported experiencing very mild side effects like headache, nausea, dizziness, irritability, eye strain, and sleep disturbances. Although, euphoria has also been reported in some people.

How to Use Light Therapy for Depression

“The best time to do light therapy is in the mornings. It can be set up in a bedroom or another comfortable space in the home. It’s recommended that the light not be in your direct line of vision, as that can be harmful rather than helpful. It’s also recommended that it be used for around 30 minutes a day.”

Talkspace therapist Bisma Anwar, MA, MSc, LMHC

While it’s clear that more research is needed for us to truly understand the benefits of using light therapy for depression, there are some very promising, good indicators of its efficacy. If you suffer from seasonal depression and think that bright light therapy or online therapy could be beneficial, ask your doctor if it’s a suitable treatment in your case. Many people experience significant benefits in a short time with no adverse effects.

Medically reviewed by: Minkyung Chung, MS, LMHC

Reviewed On: April 12, 2022