What Is Light Therapy and Is It Right For You?

A woman sitting next to a light therapy box

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What Is Light Therapy?

Light therapy, also known as phototherapy and bright light therapy, is a therapy used to treat a variety of mental health conditions. Primarily, it's used to treat a common type of depression called seasonal affective disorder (SAD), which is also known as the winter blues or seasonal depression.

Light therapy may also be helpful as a therapy for other forms of depression, sleep disorders, or other conditions.

What to Know

Since gaining recognition as a treatment in the 1980s, light therapy has been a first-line treatment for SAD, which is a subset of depression that impacts women more often than men and tends to occur from the teen years through menopause.

Lethargy, weight gain, disinterest in socializing, poor concentration, and feeling unhappy, irritable, and agitated are common symptoms of the condition.

No one knows for sure why SAD occurs but it seems to be linked with the female reproductive system, a variety of hormones, and diminished sunlight exposure.

Researchers believe the condition is triggered by a lack of exposure to natural light during the shorter, darker days of fall or winter and symptoms tend to follow a yearly seasonal pattern.

This decrease in exposure to sunlight impacts some people more severely than others, causing depression. The treatment works by giving you a boost of artificial light that mimics the effects of longer, sunnier days.

How Light Therapy Works

Light therapy is easy to use. All it takes is a light therapy box or lamp, which you simply plug in, turn on, and sit close enough to for your eyes and skin to absorb the light for an allotted amount of time. The machines themselves are typically composed of fluorescent lights on a metal reflective base with a plastic screen on top to diffuse the light and filter out harmful ultraviolet light (UV) rays.

It is important to receive 10,000 lux of exposure, and at the proper distance, which the better light boxes will permit over 30 minutes of exposure. You don't want to look directly into the device during the whole session as that could damage your eyes. Instead, the intention is that your eyes pick up the light indirectly. Typically, you should aim to be within one and a half and two feet from the lightbox, in order to reap the most benefit.

The machines give off a bright light that simulates outdoor sunshine, boosting melatonin, serotonin, and vitamin D, among other effects. However, it is important to follow the manufacturer's recommendations with respect to the actual distance needed to get the proper amount of light in 30 minutes. Some manufacturer's note a distance of 6-12 inches, so if it is 12 inches, for instance and the person sits 24 inches away, it would take an hour. If you have SAD, you'll likely start treatment in the early fall and continue throughout the winter, taking a break during the late spring and summer months.

Researchers aren't entirely sure how or why light therapy works, but studies show that the treatment does offer relief of symptoms for many people.

The light exposure provided by a lightbox is thought to trigger the production of the brain chemical serotonin, in the way natural light does. Serotonin, which is often called the "feel-good" hormone, plays an essential part in the proper functioning of your mind and body, affecting mood, emotions, motor skills, and sleep.

Exposure to light both resets the circadian rhythm of melatonin and acutely inhibits melatonin synthesis. This is why the treatment is also used to improve sleep issues, by helping to regulate the sleep/wake cycle.

Using a lightbox in the mornings can cue the body that it is daytime, jumpstarting the body's clock. Similarly, light therapy is also used to treat jet lag to help people acclimate to a new time zone.

What the Research Says

Research shows that lower levels of serotonin are associated with depression and that light therapy is an effective remedy. In fact, benefits are often seen after just one session, which typically last from 15 to 60 minutes.

One study found that positive effects tend to be seen after 20 minutes, but that the optimal duration for lightbox sessions is 40 minutes daily, over the course of several weeks.

After light therapy sessions, improvements have been found in alertness, mood, energy, attention, concentration, happiness, and other markers of depression. Additionally, while currently thought of primarily to treat SAD, light therapy is increasingly being used to treat other forms of depression and mood disorders, with promising results.

In fact, studies show that bright light therapy may an effective, fast-acting, therapy for non-seasonal forms of depression as well, including major depressive disorder (MDD). Research has also found that using a lightbox in conjunction with other therapies yields better management of symptoms.

The influx of bright light that light therapy provides is believed to prevent the mood lowering that can happen when living in an environment that only provides dim levels of light.


As noted above, light therapy may be used to treat a variety of mental health conditions and is often the first treatment recommendation for those with SAD. It can be used on its own, particularly for those with milder symptoms, but is also effective when combined with talk therapy, behavior and/or lifestyle modifications (like exercise and positive sleep habits), and medications (like anti-depressants).

In addition to seasonal affective disorder, other uses for light therapy include treating the following issues:

  • A variety of sleep disorders
  • Adjusting to a night shift work schedule
  • Dementia
  • Fatigue
  • Jet lag
  • Non-seasonal depression

Note that light therapy can also be used to treat a variety of skin conditions such as psoriasis. However, while these lamps intentionally emit ultraviolet (UV) light, light therapy devices for mental health conditions are made to block UV rays as they can be harmful to the skin and eyes if absorbed in excess.


The efficacy of light therapy is well established, particularly for use with seasonal affective disorder. As noted above, however, it's important to understand that while light therapy often offers an improvement in depression symptoms, it does not offer a cure for SAD or other conditions. The benefits received from the boost of light are short-term and need to be maintained with consistent therapy.

Minimal Side Effects

One big benefit of using bright light therapy is that most people have minimal, if any, side effects, and it has far fewer than most other treatments. Also, generally, light therapy is very safe to use and has no contraindications with other treatments.

However, those with some disorders, such as eye conditions like macular degeneration or photosensitive skin, are not good candidates for this treatment.

The reported side effects of light therapy include eyestrain, headache, irritability, or nausea. These adverse impacts are usually minimal and cease when the device is turned off or after a few days.

Moving away from the lightbox or shortening the duration of treatment can mitigate adverse issues. The normal course of treatment starts with about 15 minutes and works up from there to avoid any side effects.

Due to the fact that this treatment doesn't involve medication, it is also a safer option for those that can't or don't want to take antidepressants, such as during pregnancy. Additionally, light therapy is a good way to augment or bridge treatment to provide extra relief while waiting for the benefits of other methods to kick in.

Fast Results

Light therapy also starts working faster than most other forms of treatment, although the therapeutic effects quickly wane (within days) if the lightbox is not used regularly.

As noted above, some people report enhanced mood and generally feeling better after just one to a few sessions, with maximal results usually attained after several weeks of consistent use.

Low Cost and Accessibility

After the initial cost of buying a device, which is often covered by insurance, there are no maintenance costs except the nominal electricity to power your lightbox. Lightboxes are unobtrusive and often highly portable and adjustable making them very convenient.

Plus, once purchased, they are also easily accessible to use as needed, making treatment as easy as flipping a switch and sitting near the light.

Is It Right for You?

If you have SAD, other types of depression, or sleep issues, light therapy might be a good match for you, in conjunction with other treatments or on its own.

Talk to your doctor or mental health provider about how using a lightbox might benefit you and/or work into any other therapies you currently use. Consider if you will have the time and/or inclination to incorporate light therapy sessions into your daily routine.

If you have bipolar disorder, it is especially important to consult your medical provider before starting light therapy as this treatment may trigger mania. Studies have shown that this can be an effective treatment option for those with bipolar disorder, although more research is needed to determine the most effective protocols in terms of session length, frequency, and light strength.

Anyone starting light therapy should monitor how their moods and emotions are impacted and consult their doctor and/or therapist with any concerns or questions.

Types of Light Therapy Devices

The specific lightbox or lamp you use can be recommended by a counselor or medical provider or you can select and buy one yourself. There are many options of light therapy boxes and lamps available.

As there are few worrisome side effects or contraindications and the devices are so easy to use, it may be safe to try out this therapy on your own, particularly if you have mild symptoms—although it's always a good idea to consult your doctor first.

Aim to get a specific recommendation from your doctor or mental health provider on the type of lightbox, including light intensity and how far to sit from it, that will be safest and most effective for your treatment. They may be able to recommend specific brands or models that they have experience with as well.

Lightboxes come in a range of sizes, shapes, and strengths. You can choose one that looks like a desk lamp, a standing tablet, or an orb, among other options. They are made in lots of different styles as well to fit in with whatever style appeals to you—from those offering a more medical or practical look to those verging on design pieces.

Light Intensity

The intensity of your lightbox may vary from product to product but typically for SAD, it is recommended to use a device with a strength of 10,000 lux. Lux is the unit of measurement that measures lumens (light output) per square meter. In other words, the lux value is the strength of illumination a light source has on a square meter surface, a meter distance away from the light.

For comparison, ambient daylight typically ranges from 10,000 to 25,000 lux, sunlight clocks in from 32,000 to 100,000 lux, and an overcast day provides around 1,000 lux. Brightly lit indoor spaces, such as hospitals, may have up to around 1,000 lux, but the lighting in a typical home is around 150 lux.

If you use a device with a lux intensity lower than 10,000, you may need to increase the length of time you sit by it each day to get the same efficacy.

Other Options

Light therapy devices can come fitted in visor-like shapes that are worn on the head to provide light to the face. Other options include lightboxes that are set with a timer to wake you up with an artificial sunrise in your bedroom that gradually increases the amount of light in the room.

Some devices are portable, making them easy to take with you for travel or to and from work. There are also some light therapy products made specifically for children. The prices of these products start around $25 and go up to $200 or more.


While light therapy is a relatively simple and accessible treatment, there are ways to maximize its effectiveness. Try the following suggestions to improve your results.

Make Light Therapy a Morning Ritual

Schedule your light therapy sessions for the morning. Studies have found that early morning is usually the most effective timing, particularly as evening sessions may interfere with your sleep and/or cause insomnia in some people.

Additionally, spending a lot of time (such as a few hours) in front of a lightbox each day, even if it's not just right before bed, may also make it harder to fall asleep.

Set Aside 20 Minutes

Use your lightbox daily for around 20 minutes (or more if recommended by your counselor), ideally for a period of several weeks or more to ease your symptoms. Track how you feel after your sessions, any changes in impact from varying durations, and when you hit upon the ideal amount of time that gives you the relief you want without spending any extra time by the lightbox.

As noted above, you don't want to spend too much time (more than gives you therapeutic benefit) in light therapy, so you'll likely want to limit your exposure to an hour or so per day.

Sometimes, you might break up your session to multiple times per day if instructed by your therapist but aim to keep the total minutes below the maximum they suggest, while also doing sessions as early in the day as possible.

Use in Conjunction With Other Treatments

While many people find some depression or other condition relief when using light therapy on its own, it not a cure for your condition and is unlikely to completely relieve all symptoms. Instead, think of it as a way to reduce symptoms, help you cope, and/or augment any other treatments or therapies suggested by your counselor or doctor.

Look for Low UV Light

Not all light therapy products are safe for your skin—read the specifications closely on any lightbox you're considering buying. As noted above, be sure to choose a lightbox that emits low levels of UV light.

UV is the light that causes skin damage (and is what sunscreen protects against), so you want to make sure you're not upping your risk of developing skin cancer when using your lightbox.

Give It Time

As noted above, many people find some improvement after just one treatment, but not everyone does—and don't expect 100% relief. However, that doesn't mean light therapy won't work for you or that minimal results at first won't become more substantial over time.

In fact, studies show that consecutive sessions over the course of a few weeks tend to result in a gradual improvement in results. So, don't give up on light therapy after just one try.

A Word From Verywell

Light therapy might not be for everyone, but many people find some relief from symptoms of seasonal affective disorder, other forms of depression, and sleep issues while using these devices.

As light therapy comes without any serious side effects and is so easy to self-administer from the comfort of home, this treatment is an appealing coping option for many people with mental health conditions.

7 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Sarah Vanbuskirk
Sarah Vanbuskirk has over 20 years of experience as a writer and editor, covering a range of health, wellness, lifestyle, and family-related topics. Her work has been published in numerous magazines, newspapers, and websites, including The Spruce, Activity Connection, Glamour, PDX Parent, Self, Verywell Fit, TripSavvy, Marie Claire, and TimeOut New York.