What You Need to Know About Light Therapy for Insomnia

Light therapy is a common treatment for sleep disorders and mood disorders that affect sleep. Also called phototherapy or bright light therapy, it involves using a special lightbox at home, or sometimes simply getting sun exposure at the right time of day.

It might sound too simple to help with such a big problem, but a growing body of scientific knowledge shows that it can work. You may benefit from light therapy if you have sleep problems related to:

• Insomnia
• Circadian rhythm sleep disorders
• Seasonal affective disorder (SAD)
• Depression

What Is Light Therapy?

Light therapy is an intentional and focused use of sunlight or simulated sunlight to treat symptoms. This is typically done with a specially designed lightbox that puts out 10,000 lux. That's bright enough to be effective but substantially dimmer than the sun, so it's safe for your eyes.

While your healthcare provider may recommend it, light therapy usually is something you do yourself, at home, and it doesn't require a prescription or medical supervision. However, you'll need to acquire your own lightbox. (That may be more affordable than you think. We'll discuss that below.)

Light therapy is simple. It typically involves:

• Sitting a certain distance from a lightbox
• For a specific amount of time, which may vary by condition and severity
• At a specific time of day

Your healthcare provider can help you fill in those specifics based on your diagnosis, current research, and their clinical experience.

How Does Light Therapy Work?

The purpose of light therapy is to reset your circadian rhythm. Circadian rhythms are cycles of physical and mental functions that take place, in most people, over the course of a 24-hour period. Scientists don't fully understand how these cycles work, but research is ongoing because they are important to many aspects of health.

Most living things develop a circadian rhythm that's in sync with the light and dark cycles in their environment. In fact, scientists have found sensors in the back of human eyes that detect light and dark patterns and use them to set the circadian rhythm.

The Sleep-Wake Cycle

The sleep-wake cycle is one of the main functions of the circadian rhythm. When things work like they're supposed to, you're awake for roughly 16 hours and asleep for eight.

The body performs very different functions depending on where you are in the sleep-wake cycle. For instance, cell growth and mental function increase while you're awake, and your metabolic rate and body temperature drop when you're asleep.

Hormones are an important part of these cycles. When things are working properly, about two hours before you wake up, the body releases increased amounts of adrenaline and cortisol to prepare you for the day's activity. Melatonin, a hormone that promotes sleep, increases in response to darkness and drops off rapidly when you're exposed to bright light.

Many other processes go on that influence when you get tired and when you're most alert and energetic. People who aren't exposed to enough light during the day—or even not light from the right spectrum—can have their circadian rhythms thrown off.

Resetting Your Circadian Rhythm

A growing body of research suggests that resetting your circadian rhythm with light therapy is a beneficial aspect of treatment for several conditions.

In most cases, light therapy is recommended for first thing in the morning. ("Morning" in this case means within an hour of when you wake up.) For sleep disorders, between 30 and 40 minutes of light therapy is typical, but it may be longer for some conditions.

Keep your healthcare provider's guidance in mind when setting up your lightbox so you're in the optimal distance range. You can use the lightbox wherever it works best with your morning routine, such as:

• On your bathroom counter while you get ready for work
• On the kitchen table while you eat breakfast
• Above the desk in your home office

You can go about your regular activities—eat, check email, work on the computer—while also receiving light therapy. The important thing is that it's consistent and (unless your healthcare provider recommends a different time) soon after you wake up, whatever time of day that might be.

What About Sunlight?

It is possible to use the sun for light therapy, as long as your goal is resetting your circadian rhythm to match the natural day and night cycle. After all, lightboxes are meant to provide simulated sunlight.

If you're consistently able to take a walk, spend time outside, or sit inside near a window in the morning, this may be an option you want to try.

However, a lightbox is usually recommended, as it's easier to use consistently. Your therapy routine is less likely to be impacted, for example, by bad weather, work schedules, acute illnesses like the cold or flu, or symptoms that sap your energy and motivation.

Conditions Light Therapy May Help

Sometimes, a person's circadian rhythm is altered and doesn't function properly. This can be related to certain genetic abnormalities or medical conditions. It can also be due to shift work or jet lag, which disrupt your usual light-dark cycles. It can even happen because of late-night exposure to light from electronic devices.

When you have insomnia, other sleep disorders, or diseases that disrupt sleep, your body may benefit from extra clues as to what time of day it is.

If you work nights, have regularly changing shifts, or travel a lot, you may need to adjust your sleep-wake cycle to go against your body's natural cycles and the clues it takes from the rising or setting sun.

Insomnia

Insomnia is a common sleep disorder defined by having trouble falling asleep, staying asleep, or having quality sleep. It leaves you tired and makes functioning harder, and long-term sleep deprivation can have major impacts on your physical and mental health.

Research on light therapy for insomnia suggests a benefit. In a 2016 review of studies on light therapy for insomnia, researchers concluded that evidence showed light therapy was effective for treating insomnia, including insomnia related to Alzheimer's disease and related dementias (ADRD).

A 2017 paper specifically on light therapy for people with ADRD cited evidence that light therapy improved nighttime sleep, increased daytime wakefulness, and reduced evening agitation and behavioral problems linked to the disease, all while avoiding potential side effects of medications.

European guidelines for insomnia published in 2017 said evidence for light therapy was of low quality and needs further study, but they issued a weak recommendation in favor of using it.

So far, we don't have specific research on light therapy for different types of insomnia, such as short-term insomnia caused by stress or chronic insomnia. If results continue to be promising, that kind of research may eventually be performed.

While light therapy may benefit you, you shouldn't consider it a replacement for other treatments, such as lifestyle changes or medications recommended by your healthcare provider.

Circadian Rhythm Sleep Disorders

Several sleep disorders are directly linked to disruptions in the circadian rhythm, making a reset option especially attractive. These circadian rhythm sleep disorders are:

• Delayed sleep phase disorder: Characterized by being unable to sleep until at least two hours beyond the preferred bedtime, leaving the body unprepared to wake up in the morning
• Advanced sleep-wake phase disorder: Characterized by unintentionally going to sleep and waking up especially early, and being unable to go to sleep after waking up earlier than desired
• Jet lag: Temporary circadian disorder linked to suddenly changing several time zones due to travel
• Non-24-Hour Sleep-Wake Disorder: Characterized by shifting sleep patterns and sleep-wake cycles that are often longer than 24 hours; especially common in blind people with no light perception
• Shift work sleep disorder: Characterized by an inability to adjust to a schedule of working at night and sleeping during the day
• Irregular sleep-wake rhythm disorder (rare): Characterized by the absence of a sleep schedule due to loss of a circadian cycle; people may get enough sleep but not in a predictable pattern

Light therapy is one of the primary treatments for this group of disorders.

A 2015 paper emphasizes the importance of appropriately timed light plus melatonin and improved sleep hygiene for these disorders. The 2016 review mentioned above cited evidence of light therapy working for circadian rhythm sleep disorders in general. And a 2019 study suggested light therapy for shifting the timing of sleep in delayed and advanced sleep phase disorders.

Some healthcare providers recommend late-evening light therapy for people with advanced sleep phase disorder, since the goal is staying awake longer.

Seasonal Affective Disorder

Seasonal affective disorder (SAD) involves depression symptoms that generally come on in the fall and winter. It's believed to be caused by a lack of sunlight due to shorter days, which can disturb the circadian rhythm and impact the balance of the sleep-wake chemicals serotonin and melatonin.

Not surprisingly, given its cause, sleep disturbances are a common symptom of SAD. Some research has suggested that using light therapy through the fall and winter months may help improve symptoms of SAD by improving sleep problems. In some cases, it also can prevent SAD symptoms from developing.

Research on light therapy for treating SAD goes back decades, and it's one of the most recommended treatments. Reviews of literature from 2019 and 2020 call for larger, high-quality clinical trials but cite the effectiveness of the treatment.

Your healthcare provider may recommend light therapy in the morning, but for SAD symptoms, it's sometimes recommended for later in the day to counter the effects of the early fall and winter sunset.

While light therapy is a standard approach to treating SAD, be sure to follow all of your healthcare provider's treatment recommendations rather than trying to rely on a lightbox alone.

Depression

Depression, also called major depressive disorder or clinical depression, is yet another condition linked to circadian rhythm disruption.

People with depression are especially likely to have insomnia, and insomnia can contribute to the development of depression. Each condition may lead to the other, and they can make each other worse.

Treating sleep problems can have the added benefit of alleviating depression, and light therapy can play a role in that. One study called light therapy an "efficient antidepressant strategy," either alone or in addition to other treatments.

A review of studies on light therapy for depression states that antidepressant drugs plus light therapy were more effective than antidepressants alone. It also found that light therapy may improve people's response to antidepressants.

Light therapy is best considered a possible add-on therapy rather than a replacement for antidepressants. Be sure to follow your healthcare provider's treatment recommendations.

Other Conditions

Research has suggested that light therapy may benefit people with many other conditions, as well. These include:

• Bipolar disorder
• Parkinson's disease
• Heart disease

While aging isn't exactly a medical condition, some studies have found that many older people, and especially those who live in group-home settings, have circadian rhythm disruptions that are tied to spending most of their time in dim lighting. Researchers have recommended brighter lighting that stimulates the circadian rhythm in common areas of these facilities.

Light Therapy at Home

When using light therapy, it's important to ask your healthcare provider for specific instructions, such as how far from the lightbox you should be, how long you should use it, and what time of day may be best for you.

The American Thoracic Society has published patient information on light therapy and makes the following recommendations:

• Because the light sensors that influence your circadian rhythms are in your eyes, it's considered best if the light is hitting your eyes about equally.
• You may want to place your lightbox above where you sit for therapy (e.g., on the wall above your computer monitor or on a tall dresser or shelf across the room from your bed rather than off to the side on a nightstand.) Alternatively, you could set up two lightboxes, with one on either side.
• Turn on the other lights in the room.
• Sit about two feet from the lightbox.
• Don't stare at the light but orient your face generally toward it.
• Don't nap right after light therapy or you may nullify the effects.

Buying a Light Box

Most commercially available lightboxes put out 10,000 lux. Ask your healthcare provider if this is an appropriate light level for you. They may also recommend certain brands or styles.

The Cost

Prices range from about $20 up to a few hundred. They're available from many online retailers and drug or medical supply stores. You may also be able to find one secondhand online. Before you buy one, though, check with your insurance company to see if they'll help cover any of the cost.

Types of Lightbox

When deciding on the size of box you'd like, consider where you'd like to put it and whether you might need to move it frequently, such as taking it out of your home office on days off. If you travel frequently, you may want a portable one.

Get a lightbox that puts out low levels of UV light, which can be damaging to your skin.

Other Considerations

Give it time—it may take several weeks to see a benefit from light therapy. Make it a simple part of your routine so it's easy to be consistent.

Other types of light therapy devices are available as well, including visors and glasses. If you think these might be a better option for you, ask your healthcare provider.

Light Therapy Safety and Considerations

While light therapy is generally safe and doesn't need to be supervised by a medical professional, it can cause some side effects, which are usually mild and go away with continued use. Possible side effects are:

• Eye irritation
• Nausea
• Headaches
• Dizziness
• Anxiety or nervousness

In some people with bipolar depression, light therapy can cause mania or hypomania. However, this is rare.

Photosensitivity

Some medications and supplements can cause photosensitivity, a reaction that can lead to a rash or make you sunburn easily. If you're taking one of them, talk to your healthcare provider about whether light therapy is safe for you. These include:

• Melatonin
• Lithium
• Some antibiotics
• Isotretinoin

If you have lupus-related photosensitivity, talk to your rheumatologist before using light therapy.

Eye Diseases

People with certain eye diseases may need to be monitored by an eye healthcare provider while using light therapy. These diseases include:

• Glaucoma
• Macular degeneration
• Cataracts
• Diabetes-related eye disease

Frequently Asked Questions

Can light therapy cure insomnia?

It can help some people readjust their sleep routine and overcome insomnia. Research shows that higher light intensity has helped those with insomnia, especially people who have Alzheimer’s disease or dementia-related insomnia. But it may not help all types of sleep problems.

Why is it important to regulate your circadian rhythm?

It’ll help ensure you get enough sleep, but on top of that, regulating your circadian rhythm can influence your appetite and digestion, heart rate, body temperature, oxygen use, mood, fluid balance, hormonal secretions, and other important physiological processes.

Can light therapy help with jet lag?

Yes. Bright light exposure in the early morning can help reduce jet lag symptoms. And research shows that you might be able to prevent jet lag by having short flashes of light turn on and off while you sleep (instead of using continuous lights). Other methods of using light therapy to cure jet lag and help shift workers are also being studied.

A Word From Verywell

Sleep is a fundamental need for your physical and mental health, and mood disorders can have a significant impact on your life. If your current treatments aren't providing enough relief, talk to your healthcare provider about treatment options, including light therapy. It might be that a simple addition to your daily routine could provide a significant benefit, especially when added to other science-backed treatments.