It may seem counterintuitive, but light may be the key to better sleep.

For certain sleep disorders, particularly those related to circadian rhythm disruptions, light therapy can be a beneficial treatment.

Let’s explore light therapy for sleep, how it works, and the benefits it may have.

Light therapy is exposure to a light source that’s brighter than typical indoor light, but not as bright as direct sunlight.

It involves using a light box for a specific length of time and at the same time every day. You can do it from the comfort of your home.

Light therapy is used for a several different types of conditions, including various sleep disorders, jet lag, depression, and seasonal affective disorder (SAD).

Also known as phototherapy, light therapy may help improve the quality of your sleep by affecting certain brain chemicals associated with your sleep and mood.

If you have insomnia, it could be due to a disruption in your circadian rhythm, which is linked with your sleep-wake cycle.

Your circadian rhythm is part of your body’s internal clock that causes you to feel alert and awake during the daytime and sleepy at night.

When your circadian rhythm becomes disrupted, you may experience symptoms that range from daytime sleepiness to depression.

When used correctly, light therapy can encourage a circadian rhythm reset which, in turn, may help improve your sleep and other symptoms.

Research trials have shown the benefits of light therapy for people with sleep disorders and depression.

And a 2016 meta-analysis found that light therapy is effective for sleep problems in general, especially those involving circadian rhythms and insomnia.

Light therapy can be used for circadian rhythm sleep disorders, such as sleep onset insomnia. That’s when you have trouble falling asleep at a normal time, but no problem staying asleep. This could be due to advanced or delayed circadian rhythms.

With advanced sleep phase disorder, you tend to feel sleepy in the late afternoon or early evening. Bedtime typically occurs between 6 p.m. and 9 p.m. Because bedtime is early, you often wake up between 2 a.m. and 5 a.m.

In this instance, light therapy in the early evening hours can help reset an “early bird” internal clock.

With delayed sleep phase disorder, you tend to stay awake late into the evening, often past midnight. As a result, you also tend to wake up later in the morning.

In this instance, light therapy in the morning, right after you’ve woken up, may help help advance your internal clock and make you feel sleepy earlier in the evening.

Light therapy has also been used for:

It’s not generally recommended for sleep disorders unrelated to abnormal circadian rhythms.

Before shopping for a light box, talk to your doctor about the problems you’re having with your sleep. There are many reasons you might be having trouble sleeping well.

Your doctor can help determine if your sleep issues are due to a circadian rhythm disruption or some other underlying cause. Other treatments, with or without light therapy, may be needed.

Be sure to talk to your doctor about the safety of a light box if you:

  • have an eye problem that could be aggravated by a light box
  • have a condition, such as lupus, that makes your skin sensitive to light
  • have bipolar disorder, because light therapy may trigger mania
  • take certain medications, such as antibiotics or anti-inflammatories that increase light sensitivity
  • take the supplement St. John’s wort, which can increase light sensitivity

The most important feature of a light box is the light. Make sure that it filters harmful ultraviolet (UV) light.

Don’t use light boxes meant for skin conditions, tanning beds, or sun lamps. These types of light devices emit UV light. Not only are they the wrong kind of light for sleep and mood disorders, but they can also damage your skin and increase your risk of skin cancer.

Depending on your doctor’s recommendation, you’ll need a light intensity of 2,000 to 10,000 lux.

Before you buy a light box, think about how you want to use it. Some light boxes can sit on a table or desk. You can also buy a tall light box that sits on the floor.

If a light box is too cumbersome, you may want to consider using LED glasses. Light therapy glasses are more portable and provide more freedom of movement. A recent small study found the effectiveness of light therapy glasses to be comparable to a light box.

Ask your doctor for recommendations and choose the option that works best for your lifestyle.

Depending on the type of circadian rhythm disruption you have, light therapy is either done in the morning, soon after waking up, or in the early evening hours, before you start feeling drowsy.

Your light box should be situated about 16 to 24 inches from your face. The light has to reach your eyes, though you shouldn’t look directly into the box. It’s fine to eat, read, or use an electronic device during your session.

The important thing is to expose yourself to the light for a set amount of time — no more, no less. The length of your sessions could be 30 minutes to 2 hours, depending on the light intensity and your doctor’s recommendation.

Another key factor is consistency, so try to stick with it. You may not notice any improvement for a few days to a few weeks.

Whatever device you choose, be sure to read the safety precautions and instructions provided.

Light therapy is generally safe, though some people have minor side effects, such as:

  • eyestrain
  • headache
  • nausea
  • irritability

The side effects usually don’t last long or beyond the first few sessions. If your side effects are severe, stop light therapy and contact your doctor.

Here are some more tips for improving your sleep:

  • Eliminate blue light from your sleep environment. Remove all electronic devices or put them in a place where they won’t disturb you.
  • Stick to a regular sleep schedule. Try to go to bed around the same time each night and get up around the same time every morning.
  • Resist the urge to nap, especially later in the day.
  • Get regular exercise, but not within an hour of bedtime.
  • Keep your bedroom cool, dark, and quiet.
  • Limit caffeine to the morning hours.
  • Avoid alcohol and nicotine within several hours of going to bed.

For additional help, talk to your doctor about:

  • medications, such as melatonin or short-term sleep aids
  • chronotherapy, a type of therapy that progressively advances or delays sleep time to reset circadian rhythms

Light therapy is a noninvasive, nonpharmacological treatment for certain sleep disorders. With consistent use, light therapy may help reset your circadian rhythms and improve your sleep.

Insomnia can be a sign of an underlying health condition. Talk to your doctor before buying a light box. That way, you’ll address any health concerns, plus you’ll get insights into light intensity, session duration, and other keys to successful light therapy.