The 2020 Ultimate Guide to Bright Light Therapy

Jump to a Section:

  • Introduction: The Importance of Sunlight
  • What is Bright Light Therapy?
  • What Experts Say
  • Who should use Bright Light Therapy?
  • How to use Light Therapy Lamps
  • Selecting a Bright Light Therapy Lamp
  • Light Therapy Frequently Asked Questions

All humans need sunlight to survive and live happy, healthy lives.

All humans need sunlight to survive and live happy, healthy lives. Our exposure to sunlight aids in the production of a variety of vitamins and hormones, including melatonin and serotonin which directly affect our energy levels and emotions.

Exposure to sunlight aids in the production of a variety of vitamins and hormones which helps us sleep better, be more awake, and aids in better moods.

Melatonin is the key hormone in our body’s sleep-wake cycle, also called our circadian rhythm. Our bodies respond to darkness by producing melatonin which signals the body to prepare for sleep. When we’re exposed to sunlight in the morning, melatonin is produced sooner and helps us sleep more easily come night time. Regular sunlight exposure during the day is necessary for synchronized melatonin production and a healthy sleep and wake schedule.

Exposure to sunlight also helps maintain healthy levels of serotonin, a hormone that eventually converts to melatonin. Because serotonin transmits signals between different parts of the brain, it regulates many functions: mood, appetite, sexual desire, memory, and energy levels. Serotonin's wide application in supporting multiple bodily functions means it plays a critical role in helping you do what you want every day.

Unfortunately, in the modern-day, we don’t get enough sunlight. According to the U.S. Environmental Protection Agency, Americans spend approximately 90 percent of their time indoors, and artificial indoor light is not nearly as beneficial to our bodies as natural sunlight. As seen in the chart below, typical indoor light levels are significantly lower in intensity than those of sunlight on a spring day, and they don’t provide the amount of light exposure we need.

Americans spend approximately 90 percent of their time indoors which is not nearly enough exposure to sunlight. Our lighting chart shows the optimal times to get 10000 LUX outside compared to indoor lighting.

During the winter, the days get shorter, and our contact with the sun becomes even more limited. Many of us leave for work just as the sun is rising and don’t return home until after it has set, not getting any sunlight at all. While the amount of sunlight we need varies widely depending on our skin tone, age, and other factors, this lack of exposure can inhibit the healthy production of essential hormones. This could disrupt our sleep schedules and contribute to conditions like insomnia, depression, and seasonal affective disorder.
Bright light therapy lamps, also known as sad lamps or happy lights, provide an artificial alternative to natural light that can help solve this common problem.

Watch Our Bright Light Therapy Explainer Video


What is Bright Light Therapy?

Bright light therapy is eye exposure to an artificial light source that emits strong light, mimicking sunlight. This aids our bodies in the production of melatonin and serotonin when we have limited sunlight exposure, such as in the fall and winter. Supplementing low sunlight exposure with an artificial source can help us fall asleep more easily at night and feel happier and more energized during the day. 

Bright light therapy is eye exposure to an artificial light source that emits strong light, mimicking sunlight. This aids our bodies in the production of melatonin and serotonin when we have limited sunlight exposure, such as in the fall and winter.

A Brief History

Learn more about the history of light therapy here and here.

Does Bright Light Therapy Work?

Many studies conducted since the 1990s have found bright light therapy to be an effective treatment for circadian rhythm disorders and mood disorders.  

Research conducted in 2005 found bright light therapy lamps can be used to help treat a wide range of issues and disorders. For example, the research found exposure to bright light therapy in the morning helped patients manage sleep disorders, develop regular sleep cycles, and sleep through the night. It also found bright light therapy was effective in easing the symptoms of SAD, nonseasonal depression, senile dementia, and jetlag. Additionally, a study done in 2015 found that light therapy was just as effective as cognitive behavioral therapy in improving symptoms of acute depression.

Conditions light therapy help includes sleep disorders, S.A.D., non seasonal depression, senile dementia, jet lag, acute depression, and shift work adjustment

Certain lights such as full spectrum lights, can help with mild depression. Sometimes, people feel an uplift in mood after exposure to these lights. You can also buy vitamin D3 lights to help mimic the sun too. These lights mimic the sunlight, which can be hard to get in the winter months. Bright light therapy usually involves reading near a special type of light for 40 minutes a day. A more natural light therapy would be laying outside in the sun on a beach on a summer day.”
-Katie Ziskind, Licensed Therapist

According to Mayo Clinic, light therapy can also be used to treat skin disorders such as psoriasis. However, this involves using a type of lamp that emits UV radiation, which is different than the lamps we will be discussing in this guide. Bright light therapy lamps for sleep and mood disorders filter out UV rays to protect your eyes and skin. Lamps designed to emit UV rays such as tanning beds are not an effective alternative to bright light therapy. They emit harmful UV rays and have not been proven to treat any illness or disorder. 

The Pros & Cons of Light Therapy Lamps

There are many benefits to light therapy. It's quickly become a go-to for many that struggle with SAD or other mood conditions. We've highlighted the pros and cons of light therapy below to give you a better idea if this treatment method is right for you.

- Noninvasive: Light therapy lamps offer a noninvasive method for treating ailments such as SAD. Users only have to sit in front of them for 30 minutes per day and many bright light therapy lamps can double as task lamps.
- Safe: Therapy lamps are generaly safe. The proper lamp effectively blocks out harmful UV rays, keeping the user safe.
- Convenient: Therapy lamps make the perfect addition to any morning routine. They are easy and convenient to use, with no need to go to clinics.
- Produce little to no side effects: Unlike traditional treatment such as medications, light therapy produces little to no side effects.
- Side effects and complications can occur: There have been instances of users experiencing reactions such as headache s, insomnia, sunburn , fatigue , dry eyes and nose, and hypomania, an extended period of heightened mood

What Experts Say About Light Therapy

Dr. Carrie Lam, MD, FAAMFM, ABAARM

"When you are exposed to light, body is signaled to release the hormone cortisol, which is necessary for fighting stress. It also alerts the brain, thereby determining your mood. This is how your body reacts during the early stages of stress."

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Who Should Use Bright Light Therapy?

Bright light therapy may be helpful for you if you suffer from or are experiencing one or more of the following:

Seasonal Affective Disorder (SAD), sometimes known as seasonal depression or winter blues. Symptoms include feeling depressed most of the day, every day; low energy; trouble sleeping or oversleeping; difficulty concentrating; weight gain; and feelings of hopelessness. With SAD, these symptoms regularly begin in the fall months and persist into the winter.
Those who live in the dark blue areas on the map below may be more susceptible to this disorder. 

Areas Most Affected by SAD (Winter Blues)

Depression. Symptoms include feelings of sadness or hopelessness; loss of interest in activities you once enjoyed; trouble sleeping or oversleeping; low energy; difficulty thinking, concentrating, making decisions, or remembering things; and weight gain or weight loss. With depression, these symptoms persist year-round. 

Sleep disorders, such as insomnia. Symptoms include feeling exhausted during the day, having trouble falling asleep or staying asleep at night, and having an unusual sleep and wake cycle.

Jet lag. This is a temporary sleep disorder that typically occurs when you’ve traveled across different time zones in a short period of time. Symptoms include disturbed sleep, daytime fatigue, difficulty concentrating, stomach problems, and mood changes.

Shift Work Adjustments. Bright light therapy can help sync the body’s internal clock with unusual work shift schedules and enhance night-shift performance.

Senile Dementia. Treatable symptoms include night wandering, sundowning, and daytime sleep in patients diagnosed with senile dementia. 

Bright light therapy may not be right for you if you suffer from one or more of the following:

  • Bipolar disorder, as light therapy may trigger a manic episode
  • Systemic lupus erythematosus, or other conditions that cause your skin to be sensitive to light
  • Sunlight sensitivity caused by medication such as antibiotics, anti-inflammatories, or St. John’s Wort
  • Eye conditions that make your eyes vulnerable to light damage

Always consult your doctor before starting light therapy to ensure it is the right treatment for you. 

How to Use Light Therapy Lamps

For best results from your SAD lamp, begin your sessions shortly after waking and use the lamp for 20 to 30 minutes each morning or as recommended by your doctor. It's even better to start your sessions at the same time each morning. Consistency will help your body and internal clock adapt to seeing the light at your chosen specific time each day.

How to use light therapy lamps: For best results from your SAD lamp, begin your sessions shortly after waking and use the lamp for 20 to 30 minutes each morning or as recommended by your doctor.


When first beginning bright light therapy, start with short treatment sessions, gradually increasing as you see fit. Most users with Seasonal Affective Disorder start treatments in the early fall when cloudy days become more regular. Those with fall/winter depression may start earlier in the year and continue after rainy seasons if their condition is more severe. 

Correctly Positioning Your Bright Light Therapy Lamp 

For light therapy to be highly effective, you must get the light positioning correct. Your eyes should be approximately in the center of the light with the lamp screen tilted at roughly 15 degrees, so it is projected over you during each session. If your lamp produces 10,000 LUX, you should consult your manufacturer’s guidelines for optimal distance from the lamp. This distance is usually between 16 to 24 inches from the screen. If this is too close to your face for comfort, you can sit further away with longer sessions. Each lamp will vary based on its specifications (you can see specs for our lights here).

Correctly Positioning Your Bright Light Therapy Lamp

Do not stare directly into the light; try reading, working, eating, etc. during each session. The light should be getting straight to your eyes to be effective. It's important to note that your light will get weaker over time as the bulbs get older, losing their 10,000 LUX intensity. It's essential to replace your bulbs after two years, even if they haven't burnt out to keep treatment effective.

Keep Track of Your Treatment Sessions

The Center for Environmental Therapeutics recommends keeping a log of your progress before and after treatment sessions. Keeping track of your mood, energy levels, and eating habits will help you identify how effective your sessions are. Not only that, but they'll give you an idea if you should increase session length and occurrence.

Download our light therapy treatment tracker to keep track of your sessions: 

Take Note of Side Effects

Mayoclinic takes note that bright light therapy is generally safe. However, there can be a few minor side effects of bright light therapy, including: 

  • Eyestrain
  • Headache
  • Nausea
  • Irritability or agitation
  • Mania, euphoria, hyperactivity or anxiety associated with bipolar disorder

Usually, these side effects subside rather quickly. Side effects can be managed by adjusting your treatment time, how often you sit in front of your therapy lamp, and how close you sit. For safety, it's always advised to consult your doctor regarding side effects.

One factor to take note of is to check if any medications you take cause photosensitivity. These types of medications can make your skin sensitive to light, which can result in rashes or sunburn. You can see a list of drugs that may cause photosensitivity here. 

Combine your Treatments

Bright light therapy is highly recommended and used treatment for many different conditions. However, it should not be the only treatment used when treating conditions such as seasonal affective disorder, insomnia, and more. A 2015 study found that bright light therapy is more effective when combined with cognitive-behavioral therapy. Try implementing other types of treatments and wellness exercises such as yoga, meditation, exercise, and outdoor activities. 

Light therapy is more effective when combined with cognitive-behavioral therapy. Try implementing other types of treatments and wellness exercises such as yoga, meditation, exercise, and outdoor activities.
Selecting a Bright Light Therapy Lamp

Selecting a Bright Light Therapy Lamp

What's the difference between SAD lamps and regular office or desk lamps?

Lights used to treat seasonal depression are specifically designed to do so. Although regular lighting might help light-sensitive people, those affected by season depression require light exposure more than what standard office and desk lamps offer. Some therapeutic lamps produce anywhere from five to twenty times more lux than typical indoor lighting.
Most indoor lights have warmer color temperatures, while typically therapeutic lights will generally have cooler color temperatures to more closely simulate daylight. Light temperature closer to daylight will promote awakeness. SAD lamps are also fitted with screens that both reduce glare and UV exposure. Overall, therapeutic lights are designed to provide a safe, comfortable, and optimal treatment. 

Wellness Lamps vs Theraputic Lamps

Similar to standard office or desk lamps, devices marketed as wellness lamps may not produce the intensity of light required for therapeutic benefit. Furthermore, wellness lamps might be designed to provide relaxing ambiance, which is not the same as treating SAD. 

What to look for in a SAD Lamp?

When selecting a light box for your bright light therapy, one of the most important factors is lux. LUX measures the amount of light that reaches a surface from a given distance. To maximize the effectiveness of your therapy light treatment, 10,000 lux is the optimal amount. Going higher than 10,000 lux shows no additional benefits.  

Checklist for selecting a SAD Lamp for maximum light therapy benefits

For optimal therapeutic benefit, a larger surface area light has more lux output at further distances. The light should also be positioned to enter the eye from a angle higher than eye-level. With these considerations, a smaller desk-based light might not be optimal. However, if a smaller light is preferred for convenience, treatment duration can be adjusted to receive the same benefits. 

Bright Light Therapy Term Glossary

Color Temperature 
Color temperature refers to the color of the light emitted by a fixture. This color is sometimes referred to as a light's "warmth" or "coolness" and is measured in degrees of Kelvin. In general, warmer lights promote comfort, while cooler lights promote alertness. 

Color temperature chart

Compact Fluorescent Lighting
In compact fluorescent lighting, or CFL, a reaction between an electrical current and mercury vapor present in the bulb emits ultraviolet light (UV). The invisible UV light then reacts with phosphor coating the inside of the bulb to produce visible light.

LEDs, or light emitting diodes, produce light by running an electrical current through a microchip which then illuminates the diode. LEDs efficiently emit light and heat in a specific direction.

Lux measures how much light reaches a given surface from a measured distance. This should not be confused for lumen, a measurement for how much light a device emits. For example, the lux reaching your eye level from a 12" distance from a therapeutic light will differ from a 24" distance. The lumens produced by the light would be the same at either distance.

Ultraviolet Light
Many forms of lighting also produce ultraviolet light (UV), a form of invisible light between visible light and X-ray on the electromagnetic spectrum. Although UV has many applications, prolonged exposure can damage the skin, so bright light therapy lamp treatments filter out UV exposure.

Blue vs Full-Spectrum Therapy Lights
A major topic is what the difference between blue and full spectrum light is? Blue light has been proven to be more effective than full-spectrum in treating SAD and restoring energy levels. However, it should be warned that blue light can be harmful to the eyes, especially if you are taking any medications. Full-spectrum light has traces of blue light in it, but is much safer than just blue light.

frequently asked light therapy questions

How long does it take for light therapy to work?

The time it takes for light therapy to work depends on a variety of factors such as sleep schedule and time, eating habits, the amount of caffeine intake, physical activity, and prexisting conditions. Light therapy can take as little as 2-3 days or even 2-3 weeks. It's always best to accompany light therapy with a healthy diet, physical activity, and a healthy amount of sleep. When light therapy does work, you'll feel more energy, sleep better, and have an improved mental well-being.

How long does it take to reset your circadian rhythm?

Your circadian rhythm is at the center of why light therapy works. But resetting your circadian rhythm and how long it takes depends on the condition. It can take up to a month or even longer based on what condition is causing it to be thrown off. If you're simply adjusting to a new time zone, it can take as little as one day or up to one month if the trip is longer.

Can I use light therapy all day?

In short, yes you can. However, it should be done with caution. Those with more sensitivity to light may experience a feeling similar to consuming caffeine before bed. This may be a result from your circadian rhythm being thrown off with too much exposure to light. It's always best practice to ease yourself into light therapy with 30 minute sessions in the morning. Then you can increase your treatment as you see fit.

Does light therapy help anxiety?

Yes, light therapy can help with anxiety. Studies found light therapy to help reduce anxiety in adults. 

Can you use a sad light too much?

Yes, but this depends on a case-by-case basis. It is always best to use light therapy in the early morning, when the sun it rising. There has been reports of users not being able to sleep because they used their therapy lamp all day or later in the daytime. 

What are the health benefits of sunlight?

The sun is essential to being and feeling healthy. Exposure to sunlight provides us with a health dose of vitamin D for stronger bones and an immune system, it increases your quality of sleep, aids in weight loss by shrinking fat cells, and improves energy and mood levels by increasing your serotonin levels.

Learn More About Bright Light Therapy

5 Common Light Therapy Mistakes and Misuses

5 Common Light Therapy Mistakes and Misuses

Light therapy lamps are great for those that struggle with the winter blues or just don't get enough sunlight. For many, they can enhance the quality of life greatly. However, they do require a small learning curve to be effective. We've compiled the top five most common light therapy mistakes and misuses to avoid. Read this to ensure you get the most out of your bright light therapy lamp.

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Circadian Rhythm: What it is, How it works, and How to fix/Maintain Yours

Do you struggle with your energy and sleep levels? Chances are, your circadian rhythm is thrown off. In this article, we cover what circadian rhythm is, how it impacts your health and wellness, how to fix a broken circadian rhythm, and ways to keep yourself energized and healthy by maintaining it.

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7 Ways to Treat Seasonal Depression

7 Ways to Treat Seasonal Depression

As the days get shorter and shorter during the fall and winter months, our exposure to sunlight and time spent outside, unfortunately, becomes limited. This can cause many people to experience a drop in their mood during these seasons and feel more depressed, sluggish, and hopeless than they do in the spring or summer. There are steps you can take to ease the symptoms and treat your seasonal depression, so it doesn’t get the best of you this winter.

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Buyer's Guide: Selecting the Right Therapy Lamp

Our light therapy lamp guide goes over everything you need to know when selecting a light therapy lamp from sizing, light intensity, unique features, and more. Our buyer's guide offers a complete light therapy lamp comparison chart to help you select the perfect therapy lamp for your needs and condition as well as FAQ's.

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About the Author

Brandon Landgraf is the Digital Marketing Manager for Carex Health Brands. He finds passion and fulfillment in creating content that enhances, improves, and enlivens others' quality of life. All of his written work is formulated to not only offer essential advice and tips but back it with proven studies and experts. His mission is to connect with readers and provide steps to make their lives better.

You can connect with him on LinkedIn here.

About Carex Health Brands

Carex is your one-stop shop for home medical equipment and for products that assist caregivers with providing the best possible support and care for their loved ones. Carex Health Brands has been the branded leader in in-home, self-care medical products for over 35 years. Our goal is to improve the lives of our customers by bring them quality products that bring dignity back to their lives. With our three nationally distributed brands, Carex Health Brands serves national, regional and independent food, drug and mass retailers along with wholesalers, distributors and medical dealers.

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