How Do SAD Lamps Work? Everything You Need to Know.

SAD light

When you are suffering from seasonal affective disorder or SAD, the SAD lamp is going to be your trusted companion. But not for the entire day.

Read on to find out exactly how SAD lamps work.


Just in case this is your first time hearing about the SAD lamp, allow me to explain. The lamp is simply called a SAD lamp in reference to the seasonal affective disorder (SAD) that it seeks to treat.

First of all

The generic name for such lamps is light box as it is used in light therapy or phototherapy. The therapy is a medical treatment.

The process involves exposing oneself to light to treat medical conditions. 

When is phototherapy used?

  • To treat skin disorders like psoriasis and vitiligo.
  • To treat newborn jaundice. 
  • To treat some cancer symptoms.
  • To treat mood and sleep disorders including SAD.


Phototherapy is actually an ancient medical treatment. It was used as far back as 3,500 years ago

Egyptian and Indian healers reportedly used them as a complementary treatment for skin diseases particularly vitiligo.


Back then

Light treatment phototherapy back in the day is the direct exposure to sunlight. Of course, that treatment will only work in tandem with the ingestion of herbs.

Modern phototherapy

This was established by Danish physician Niels Ryberg Finsen.

In 1903, he was awarded the Nobel Prize in Medicine and Physiology for his use of light radiation in the treatment of lupus vulgaris also known as tuberculosis luposa.

Finsen used “chemical rays” lamp for the treatment.

In the case of SAD

Phototherapy uses a specialized light box to treat seasonal disorder.

Understanding SAD

As its full name suggests, this kind of affliction is seasonal. It is often felt during the colder months–starting in autumn until the winter.


It has something to do with your circadian rhythm or body clock. Colder seasons are characterized by shorter days and longer nights.

This results in less sunlight, which also results in the disruption of your body clock.

In relation to that

Your sleep pattern will most likely be affected. Since the nights are longer, you might end up spending more time sleeping.


Since it’s cold, you might crave for more carbohydrates in your diet. This may lead to weight gain.

When you gain weight, chances are you become more sluggish.


When you have extra weight, you are slower and you become more dull. In other words, you have low energy.

Trees in winter

News flash:

There is such a thing as spring and summer SAD.

As opposed to the fall and winter SAD, you might have trouble sleeping if you are experiencing spring and summer SAD. 

Can this really be true?

Logically, yes! Because during the hotter season, there are longer days and shorter nights.

Again, your circadian rhythm has been disrupted.


As opposed to the fall and winter SAD, you might develop poor appetite during this time. This will lead to weight loss. 

Another telltale of the SAD during the hotter months is anxiety or agitation.


The fall or winter SAD is the more prominent form of the seasonal depression.

But remember this:

Fall or winter SAD is not the winter blues. The two are different!

A good rule of thumb to determine if you have SAD is if you have been experiencing depressive behavior for at least two weeks. 


Winter blues is not really diagnosed by doctors. It is mostly just a mood.

More often, you feel blue during winter because of the stress of the holidays. Or it could be because you are missing loved ones.

You feel sad during winter and that’s that. It can just clear up within a few days.

On the other hand

SAD is a clinical diagnosis.

Symptoms of SAD

  • Being depressed every day.
  • Losing interest in hobbies you used to enjoy.
  • Sleeping disorder–either you sleep too much or you sleep too little.
  • Change in appetite or weight.
  • Inability to concentrate.
  • Thoughts of suicide or death. 
Man sitting down looking sad

Other causes of SAD:

  • Low serotonin level – Serotonin is a chemical that contributes to a person’s feeling of happiness. It is sometimes called the happy chemical. Low serotonin level can cause depression. Reduced sunlight may cause the serotonin level to go down.
  • Low melatonin level – Melatonin is a natural hormone in the body. It regulates a person’s sleep-wake cycle. A change in the season could cause imbalance in a person’s melatonin levels.

The Worst Effects of SAD

If you are feeling depressed, you need to see a doctor. If you don’t do something about SAD, it could lead to worse things.


Usually, SAD will lead people to think about death. But as the depression gets worse, people with SAD think about suicide.

Suicidal thoughts are bad enough. They stress people out.

Death by suicide is the worst thing that could happen. So if you are feeling down or if you know someone who is feeling down, make an appointment with a doctor right away.

Substance abuse

Drinking alcohol can be associated with having fun. So some people who are experiencing SAD would think that it’s a solution to their sadness.

Recreational drugs are associated with being high. So if you are feeling low due to depression, you might turn to things that can make you high.

These things lead people to abuse toxic and addictive substances.

Social withdrawal

You are bound to lose friends if you don’t do something about SAD. 

The unfortunate thing is that you don’t even know that you are doing it. On the part of your friends, they are also not aware why you are no longer in touch with them.

Life without friends is one of the worst things in life. 

Eating disorders

There are times, when you are down, you don’t feel like eating. Or it could be that your mind was too wrapped up with feeling sad that you failed to recognize the stimulus that tells your brain that you are hungry.

If you don’t eat right and if you are missing meals, it might lead to a bigger problem like a disorder.

SAD light in front of book

Anxiety disorder

It’s okay to be anxious, but if it becomes a disorder, then it’s a real problem. It’s actually debilitating.

When you have an anxiety disorder, you are fearful all the time. This will prevent you from doing things that you regularly do. 

As a result, you might stop going to work.

In conclusion

If you think you have SAD, see a doctor right away.

How SAD Lamps Work

Light therapy using a SAD lamp is just one of the interventions of the doctor.

So how do SAD lamps work?

Let’s get into it

One of the reasons why people experience SAD is the lack of sunlight. The purpose of light therapy is to fill the void left by sunlight.


It will be in the form of a light box, which in this case, is called a SAD lamp.

The lamp mimics sunlight but without the harmful effects: UV rays. 


The SAD lamp should have between 2,500 and 10,00 lux. The lux refers to the unit of illuminance. A single lux entails one lumen for every square meter.

To understand

  • A moonless sky has a lux of 0.0001
  • Dark areas: 20 to 50 lux
  • Office lighting: 320 to 500 lux
  • Sunrise or sunset: 400 lux
  • Overcast day: 1,000 lux
  • Full daylight: 10,000 to 25,000 lux
  • Direct sunlight: 32,000 to 100,000 lux


You need a 10,000 lux SAD lamp to actually feel the effect of the sun on you.

Common recommendation

Based on usual recommendations from medical experts, people should do light therapy early in the morning. There is no specific time but it is advised that you do it within 30 minutes of waking up. 

You should be within a foot or two away from the SAD lamp for it to work. 

SAD light


You should not look at the lamp directly, but you have to keep your eyes open. You want the mimicked daylight to actually hit the eyes.

You can do something while doing light therapy.

For example:

You can put your SAD lamp on a desk. In the morning, when you do your therapy, you can read the newspaper while the lamp is turned on with the light hitting you just right. 

You may also do some work if that’s what you want. Or read the latest novel if you’re into that.

To be certain

Ask your doctor for their recommendation about how long you can stay near the light. You may also ask for the specific SAD lamp that would be good for you.


Studies regarding the full effects of SAD lamps on people are continuing. There is a working theory that exposure to SAD lamps helps produce serotonin naturally.

Advantages of Light Therapy

One of the best things about using a SAD lamp is that it is not invasive. It is just like any desk lamp.

It is safe and a convenient form of therapy because you don’t even have to go anywhere. It is a short walk from your bed to your desk. 

Beyond that

The use of SAD lamps is associated with zero to minimal side effects.


If you feel that the use of a SAD lamp is not working–if you continue to feel depressed despite doing light therapy–then see your doctor again.

Perhaps you need a different intervention.


You may continue to use the SAD lamp even if the doctor has prescribed pills for you or another form of therapy. 


If you are feeling depressed particularly during the change of the season, it would be a good idea to try light therapy. You need to consult with the doctor, though, about the best SAD lamp for you to use.

SAD lamps will mimic daylight for you!

The most common reason for seasonal depression is the lack of sunlight. But with the right SAD lamp, you can have your own daylight inside the house – even inside your bedroom if that’s your preference. 

You Might Also Like…

Now that you know how SAD lamps work, you might want to know if it is safe.

If you are convinced that light therapy is good for you, here is a list of the best SAD lamps of the year. 

Find out more about how SAD lamps here.

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