Skip to content
WebMD: Better information. Better health.
 
Other search tools:Symptoms|Doctors|Medical Dictionary

Information and Resources

Font Size
A
A
A

Light therapy

What is light therapy?

Light therapy (phototherapy) is exposure to light that is brighter than indoor light but not as bright as direct sunlight. Do not use ultraviolet light, full-spectrum light, heat lamps, or tanning lamps for light therapy.

Light therapy may help with depression, jet lag, and sleep disorders. It may help reset your "biological clock" (circadian rhythms), which controls sleeping and waking.

Typically, you sit in front of a high-intensity fluorescent lamp for 30 minutes to 2 hours each morning.

What is light therapy used for?

People use light therapy to treat seasonal affective disorder (SAD), which is depression related to shorter days and reduced sunlight exposure during the fall and winter months. Most people with SAD feel better after they use light therapy. This may be because light therapy replaces the lost sunlight exposure and resets the body's internal clock.

When should light therapy be used?

Light therapy may be most effective when you use it first thing in the morning when you wake up. You and your doctor or therapist can determine when light therapy works best for you. Response to this therapy usually occurs within 2 to 4 days, but it may take up to 3 weeks of light therapy before symptoms of SAD (such as depression) are relieved.

It's not clear how well light therapy works at other times of the day. But some people with SAD (perhaps those who wake up early in the morning) may find it helpful to use light therapy for 1 to 2 hours in the evening, stopping at least 1 hour before bedtime.

Is light therapy safe?

Light therapy generally is safe, and you may use it together with other treatments. If symptoms of depression do not improve, or if they become worse, it is important to follow up with your doctor or therapist.

The most common side effects of light therapy include:

  • Eyestrain or visual disturbances.
  • Headaches.
  • Agitation or feeling "wired."
  • Nausea.
  • Sweating.

You can relieve these side effects by decreasing the amount of time you spend under the light.

People who have sensitive eyes or skin should not use light therapy without first consulting a doctor.

Always tell your doctor if you are using an alternative therapy or if you are thinking about combining an alternative therapy with your conventional medical treatment. It may not be safe to forgo your conventional medical treatment and rely only on an alternative therapy.

By Healthwise Staff
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer Marc S. Micozzi, MD, PhD - Complementary and Alternative Medicine
Last Revised June 30, 2009

WebMD Medical Reference from Healthwise

Last Updated: June 30, 2009
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

Hot Topics

Health Solutions From Our Sponsors

WebMD Video: Now Playing

Click here to wach video: Michelle Obama’s Nutrition Tips for Moms

First Lady Michelle Obama shares tips on parenting with moms and other audience members in a WebMD Town Hall meeting in Miami, Florida.

Click here to watch video: Michelle Obama’s Nutrition Tips for Moms

Popular Slideshows & Tools on WebMD

puppy eating
What you need to know.
Ra Management Get A Personalized Report
Assess your symptoms.
Xray of foot highlighting gout
Causes, symptoms and treatments.
Concentration Killers Slideshow
What's robbing your focus?
brain scan
Recognizing symptoms.
group beer toast
Do you know your suds?
Diabetic tools
Symptoms, causes, treatments.
thumbnail for fatigue slideshow
Causes, fixes for fatigue.
thumbnail for Brain Food slideshow
Foods that can help you focus.
Hot cup of coffee
The facts about that cup of joe.
Wendy’s Chicken Club
Double-fisted diet wreckers.

Women's Health Newsletter

Find out what women really need.