Before You Buy a Light Box for Seasonal Affective Disorder

Not all light boxes meet the recommended requirements for treating SAD

What to consider before buying a light box

Verywell / Alex Dos Diaz

There are many light box products on the market that claim to help seasonal affective disorder (SAD), but here is what you should know before you invest in one. Not all light boxes meet the recommended requirements for treating SAD.

What Is Seasonal Affective Disorder?

Seasonal affective disorder (SAD) is a subtype of depression that's related to changes in seasons. The current formal diagnosis is major depressive disorder with a seasonal pattern. As such, it begins and ends at about the same time every year.

If you're like most people with SAD, your symptoms start in the late fall or early winter and continue through the winter months, sapping your energy and making you feel moody. Less often, SAD causes depression in the spring or early summer.

In either case, symptoms may start out mild and become more severe as the season progresses. Common symptoms of SAD include:

  • Feelings of depression come and go at the same time each year, usually starting in the fall and winter, but in some cases in the summer
  • A lack of energy; feelings of fatigue and lethargy; sleeping more than usual
  • Increased appetite, sometimes accompanied by weight gain
  • Cravings for high-carb and sugary foods
  • Difficulty focusing and concentrating on normal daily tasks
  • More severe symptoms of premenstrual syndrome (PMS) or premenstrual dysphoric disorder (PMDD)
  • Withdrawing from friends and family
  • Low libido
  • Feelings of anxiety

Don't brush off that yearly feeling as simply a case of the "winter blues" or a seasonal funk that you have to tough out on your own. Take steps to keep your mood and motivation steady throughout the year.

SAD and Major Depression

Seasonal affective disorder is a subtype of major depression that comes and goes based on seasons. So people with SAD will be experiencing symptoms of major depression, such as:

  • Feeling depressed most of the day, nearly every day
  • Feeling hopeless or worthless
  • Having low energy
  • Losing interest in activities you once enjoyed
  • Having problems with sleeping
  • Experiencing changes in your appetite or weight
  • Feeling sluggish or agitated
  • Having difficulty concentrating
  • Having thoughts of death or suicide

If you are having suicidal thoughts, contact the National Suicide Prevention Lifeline at 988 for support and assistance from a trained counselor. If you or a loved one are in immediate danger, call 911.

For more mental health resources, see our National Helpline Database.

Types of SAD

There are two different forms of seasonal affective disorder; fall/winter SAD and spring/summer SAD. Symptoms specific to winter-onset SAD, which is sometimes called winter depression, may include feelings of irritability, low energy, social withdrawal, hypersensitivity to rejection, and a heavy feeling in the arms and legs that begin starting the fall and winter months.

Symptoms specific to summer-onset SAD, sometimes called summer depression, may include depression, insomnia, weight loss, poor appetite, and anxiety that begin in the spring and summer months of the year.

Bright Light Therapy

If you are diagnosed with SAD, there are a number of different treatment options. Treatment for SAD may include bright light therapy (phototherapy), psychotherapy, and medications.

Research has shown light therapy to be effective for 50% to 80% of people with SAD. Symptom relief can occur within the first week of treatment; however, treatment is continued through the season to avoid relapse.

Light therapy is also being researched in other conditions affected by circadian rhythms, such as bipolar disorder, eating disorders, and attention-deficit/hyperactivity disorder (ADHD).

In order for light therapy to be effective, you need to use your light box for at least 30 minutes each day. And to fit with the natural cycle of our circadian rhythm, the light box is generally used first thing in the morning.

The effect of light therapy is dependent on your eyes, rather than your skin. While direct exposure to the retina is important, you should avoid looking directly at the light.

You should position the light therapy box 12-15 inches in front of your face while being sure to look elsewhere. You can try doing something to stay busy and distracted from the light such as reading a book, putting on make-up, watching television, or using your computer. 

If the bright light is aversive, it can be positioned slightly above you, with the light shining downward toward the eyes at a 30-degree angle.

Before You Buy a Light Therapy Box

While light boxes are usually safe and effective, they are not regulated or approved by the FDA for treating SAD. There are, however, requirements recommended by the Center for Environmental Therapeutics (CET) for effective light box therapy. Make sure that any unit you purchase meets these specifications.

Talk to Your Doctor First

Some insurance companies are beginning to cover the expense of a light therapy box. While you can buy one without a prescription, always talk to your doctor before you begin treatment with a light box.

There are some cases in which light therapy may not be advisable, such as if you have bipolar disorder and have concerns about triggering a manic episode.

If you have eye conditions such as eye damage, glaucoma, or cataracts, you should consult with your ophthalmologist before using a light box.

Clinical Testing

Since the research was published, the market has been flooded with light therapy box options. Some only meet the criteria for illumination, but there are other things to look for. The light box that you buy should have data from peer-reviewed clinical trials to back its effectiveness for treating SAD symptoms.

Sufficient Output

When you are seated at a comfortable distance from the light box, it should provide you with 10,000 lux of illumination. Avoid products with missing or unverified specifications.

Indoor lighting is usually 100-150 lux, so light therapy of 10,000 lux is similar to being outside on a bright sunny day and is 66-100 times the amount of normal indoor lighting.

Light spectrum

Light therapy boxes with the full-light spectrum or bluish light features are effective, but have not been proven to be more effective than the standard white light spectrum.

UV Filters

Fluorescent lamps should have a smooth diffusing polycarbonate screen to filter out harmful ultraviolet (UV) rays. The light box you choose should filter out more than 99% of UV light to avoid damage to your eyes and skin.

Minimize Glare

Many light boxes are designed to sit at an angle shining upward toward your eyes. In order to minimize glare, the light can be positioned to project downward toward the eyes at an angle. Some light boxes are specifically designed for this position.

Sufficient Size

A light box with a larger surface area of approximately 200 square inches is recommended (example: 16 by 13 inches). While smaller boxes may be more convenient and less bulky, be aware that even small head movements can take the eyes out of the therapeutic range of the light, and they may need to be positioned even closer to you.

Reduce or Prevent Symptoms

In addition to light therapy, there are also steps you can take that might help prevent SAD or minimize the severity of your symptoms:

  • Increase your exposure to light throughout the day, particularly during the fall and winter months. Increase the lighting in your home if possible, keep your curtains and blinds open to let in light, and spend a little time outside each day.
  • Get regular exercise. Increasing the amount of physical activity you get each day may help relieve some feelings of depression. Going for a walk or jog outside each day may be particularly helpful since it also includes increased sun exposure.
  • Try taking a vitamin D supplement. While research is inconclusive, some evidence suggests that increasing the amount of vitamin D in your diet may help prevent or relieve SAD. Always talk to your doctor before starting on any supplement in order to prevent potential drug interactions with other medications you might be taking.
  • Reduce your caffeine intake. Stick to only drinking caffeinated beverages such as tea, coffee, and soda in the morning. Drinking caffeine later in the day may interfere with your ability to sleep well at night, and poor sleep may exacerbate feelings of depression.

A Word From Verywell

Bright light therapy has been researched for decades and can be an easy, cost-effective way to treat depressive symptoms triggered by seasonal changes. If you have been using light therapy but still have symptoms of SAD, talk to your doctor. You may need different or additional treatments such as medications or psychotherapy to find relief from your seasonal depression.

13 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.
  1. National Institute of Mental Health. Seasonal affective disorder.

  2. Rhodes S. 5 triggers for seasonal affective disorder in the summer. Michigan Medicine, University of Michigan.

  3. Raffi E, Freeman M. The etiology of premenstrual dysphoric disorder: 5 interwoven pieces. Current Psychiatry. 2017;16(9):20-28.

  4. Harvard Health Publishing. Seasonal affective disorder.

  5. Meesters Y, Jansen JHC, Beersma DGM, Bouhuys AL, Van Den Hoofdakker RH. Light therapy for seasonal affective disorder. The effects of timing. Br J Psychiatry. 1995;166(5):607–612. doi:10.1192/bjp.166.5.607

  6. Campbell PD, Miller AM, Woesner ME. Bright light therapy: Seasonal affective disorder and beyondEinstein J Biol Med. 2017;32:E13-E25.

  7. Center for Environmental Therapeutics. Light box selection criteria.

  8. Sadlamps.org. Choosing a light therapy box.

  9. Notis D. The best SAD lamps, according to experts. New York Magazine.

  10. Belvederi Murri M, Ekkekakis P, Magagnoli M, et al. Physical exercise in major depression: Reducing the mortality gap while improving clinical outcomes. Front Psychiatry. 2018;9:762. doi:10.3389/fpsyt.2018.00762

  11. Frandsen TB, Pareek M, Hansen JP, Nielsen CT. Vitamin D supplementation for treatment of seasonal affective symptoms in healthcare professionals: A double-blind randomised placebo-controlled trialBMC Res Notes. 2014;(7):528. doi:10.1186/1756-0500-7-528

  12. Al-Abri MA. Sleep deprivation and depression: A bi-directional association. Sultan Qaboos Univ Med J. 2015;15(1):e4-6.

  13. Forneris CA, Nussbaumer B, Kaminski-hartenthaler A, et al. Psychological therapies for preventing seasonal affective disorder. Cochrane Database Syst Rev; 2015. doi:10.1002/14651858.CD011270.pub2

By Nancy Schimelpfening
Nancy Schimelpfening, MS is the administrator for the non-profit depression support group Depression Sanctuary. Nancy has a lifetime of experience with depression, experiencing firsthand how devastating this illness can be.