Light therapy: What is it and how can it benefit our health?

Published 18 Nov 2021 • By Courtney Johnson

We’ve all experienced that feeling of “winter blues” as the seasons transition from fall to winter. And for some people, these “blues” may be even more severe, in the form of major depressive disorder with seasonal patterns. Light therapy is often prescribed to treat seasonal depression, but did you know that it can be effective in treating other health conditions? 

So, what is light therapy exactly? When is it prescribed? What conditions does it treat? 

We explain it all in our article! 

Light therapy: What is it and how can it benefit our health?

What is light therapy? 

Light therapy, also called phototherapy or heliotherapy, is a medical treatment using natural or artificial light to treat a health condition. 

Light therapy has been used to improve our health for centuries, with the earliest evidence dating back to ancient Egypt and India, where people used sunlight to treat conditions such as vitiligo. 

Phototherapy in the modern age was developed by Danish-Faroese physician and scientist Niels Ryberg Finsen in the late 19th century. Motivated by his own diagnosis of Niemann-Pick disease, Finsen used sunlight and ultraviolet light (UV) to treat lupus vulgaris, a type of tuberculosis affecting the skin. His pioneering work led him to win the Nobel Prize in Physiology in 1903. 

Today, light therapy has expanded to a variety of applications, using sunlight, halogen lights, fluorescent light bulbs, or light emitting diodes (LEDs). The type of therapy and type of light used depends on the condition. 

What health conditions can light therapy treat and how? 

When you think of light therapy, seasonal affective disorder (SAD) may first come to mind. But, in fact, light therapy is used to treat a number of conditions. 

These may include: 

Mood and sleep disorders

Major depressive disorder (MDD) with seasonal patterns 

Phototherapy is most commonly used to treat seasonal affective disorder, which is now referred to as major depressive disorder (MDD) with seasonal patterns. This is a type of depression that occurs during a particular time of year, typically in the winter months where there is less sunlight. 

Light therapy for MDD with seasonal patterns uses a lightbox, or a specially designed box that lets off continuous soft light in the range of 2,500-10,000 lux (a lux is a measurement of light brightness).

Research has proposed a few theories as to why light therapy is effective on depression, such as: 

  • It affects the biological clock by balancing the brain’s circadian rhythm (the body’s 24-hour clock) 
  • It contributes to stable, consistent sleep patterns 
  • It increases alertness 
  • It balances the activation of serotonin in the brain, an important player in regulating mood 

Treatment is typically prescribed in the fall through early spring, and usual bright light therapy starts with 30-minute morning sessions with 10,000 lux, though this may vary depending on the patient. The more powerful the lightbox, the shorter the session will be. 

Light therapy is also being explored for other types of depression, but researchers are not yet in agreement over its effectiveness. 

Sleep disorders 

As mentioned above, light therapy has been found to impact our body’s inner clock that regulates our waking and sleeping cycles. Sometimes this circadian rhythm is disrupted and needs to be reset. 

Phototherapy can be prescribed in people who have circadian rhythm sleep disorders like delayed sleep phase syndrome (DSPS). Patients with DSPS, as its name implies, have their sleeping phases delayed hours beyond what is considered “normal,” meaning they often cannot fall asleep until very late at night or close to sunrise. Light therapy can help re-regulate their sleep schedule to more normal sleeping hours.

Skin conditions

Light therapy can also be used to treat a number of skin conditions, especially those that have failed to respond to standard treatments or that are inflammatory in nature. 

Conditions that are commonly treated with light therapy include: 

  • Vitiligo 
  • Psoriasis
  • Eczema 
  • Itchy skin 
  • Cutaneous T-cell lymphoma (CTCL)  

Phototherapy for skin conditions utilises UV light to slow inflammation and skin cell growth. There are three types of UV light therapy used for skin disorders: 

  • Broadband UVB light: this uses a wide range of UVB rays, which are present in sunlight. 
  • Narrowband UVB light: this uses a smaller range, high intensity UVB light, and is the most common type of light therapy. 
  • Psoralen UVA (PUVA): this uses psoralen, a compound coming from plants, that helps the body better absorb UVA. It can be applied to the skin or taken in pill-form. Because this form of phototherapy can cause a number of side effects, it is usually the last course after other treatments have failed. 

Cancers and Precancers 

For certain cancers and precancers, a type of light therapy, called photodynamic therapy, can be used.

Photodynamic therapy involves the use of a photosensitising drug in combination with light. Photosensitisers are applied to the skin, and when light comes in contact with the skin, it creates an interaction with the drug to produce a form of oxygen called an oxygen radical that kills cancer cells in the affected area. 

This type of therapy can be used to treat: 

  • Endobronchial cancer (a type of lung cancer) 
  • Oesophageal cancer
  • Barrett’s oesophagus (a precancerous complication of GERD

Photodynamic therapy is sometimes also referred to as photoradiation therapy or photochemotherapy

For new-borns 

Light therapy has been used for decades to treat both jaundice and hyperbilirubinemia in new-born babies. These two conditions cause a baby’s eyes, skin, and tissues to turn yellow. This yellowing is caused by excess bilirubin, a pigment created by the breakdown of red blood cells (haemolysis)

Light effectively reduces bilirubin levels by breaking down the pigment so that the body can eliminate it properly. 

Jaundice is typically treated by placing the baby under fluorescent lamps or halogen spotlights with his or her eyes protected. A newer version of this therapy utilizes “biliblankets,” or blankets with fibreoptic pads or LED lights that shine blue light onto the baby’s body.


As we’ve illustrated, light therapy can be a helpful tool for keeping us in good health. The door is still open to new applications; scientists are currently exploring the possibility of using phototherapy to treat hair loss and diabetic retinopathy

It is important to note, however, that light therapy does have some risks. UV rays can be damaging to skin cells, causing premature aging, and potentially leading to skin cancer. Additionally, frequent sessions of light therapy can suppress the immune system, making the body more vulnerable to infection, diseases, and certain cancers. 

Light therapy is also not advised in people who are pregnant or nursing, have liver disease, lupus, or a family history of skin cancer

If you’re interested in phototherapy, make sure to reach out to your doctor. He or she can help you determine if it’s right for you. 

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Take care!



robjmckinney • Ambassador
on 20/11/2021

I worry on this one as it sounds like quackery because Oxygen O2 does not vary as a base element. Any change makes it quite different material like adding Hydrogen H it forms water. There is no adding to or varing oxygen, oxygen is oxygen we can mix it but not create another form of oxygen.

It does need some GP or speclist imput to ensure it is the right treatment for you and if you are using creams on you skin a review is needed. So at a guess your GP advises you to get treatment through the NHS where it will be supervised medically it should be okay. There are plenty of lamps online that you can buy but the concern must be without medical oversight it may do more damage than good.

Light boxes do help some people and where you are depreased during the dark winter months perhaps a little on the matter will work.

Baldness, I think if this had been a real solution it would have been on every street corner and been one of the most successful businesses in the world. I must admit I tried the rat's urine ingredient thirty odd years ago before accepting the cards dealt to me in life. So why have I not heard of a successful light treatment for baldness that works.

Curing cancers when certain light causes it sounds a little strange as the frequencies that cause and cure are quite close. But how does it reach the internals of the throat and neck is a question. The tortue of radiotheraphy of being strapped to a bench while irradiated was appalling to me. So I wonder how this works withour some light emitting device half way down your throat is a good one, externally well we have to much in the way.

But if it is through your GP it should be okay but bought from the internet without medical supervision perhaps not, stay safe!

on 20/11/2021

Thank yo for the interesting article. I have to say that I totally agree with robjmckinney's comment above. I personally do not suffer from SAD or depression, so I would not consider it for myself any ways. Even if i did, looking at the risks involved, is not worth acting on it, for me, that is any way

Courtney_J • Community manager
on 22/11/2021

@robjmckinney Hello Rob, as with all of our articles, what we have published in no way substitutes proper medical advice from a medical professional. This article is meant to highlight a lesser-known treatment and explain its different possible medical applications.

If you'd like to learn more about how it is used in the case of cancers and precancers, the NHS and the NIH both have articles on it here: Photodynamic therapy (PDT), NHS, Photodynamic Therapy for Cancer, NIH.

Possible application for baldness and diabetic retinopathy are still in the research stages, as we stated in the article.

Take care,

robjmckinney • Ambassador
on 23/11/2021

FAO Courtney Community manager

I think you may have misinterpreting my post, it is not a concern of medical servicies and Doctors giving help or treatment. My concern was desperate people may opt for people to access equipment online and self help themselves without medical supervision. People with serious illnesses like cancer or suspect such issues must seek help from professionals and not resort to quackery.

I did brief myself with the various information before expressing my opinion and concerns for quackery. I have some personal experience of quackery leading to my brother's death by cancer plus baldness and diabetic retinopathy. Quackery is getting more popular within the NHS and as I say baldness cures would be worth billions and be on every street corner.

We must encourage people to seek help from medical professionals first before promoting 'alternative medicines' or people will die or will be ripped off!

Many thanks


on 15/01/2022

I have used a light box for s.a.d a couple of times but had to stop using it as it made me hyperactive which affected my sleep badly. I am a hyper person anyway so that could be partly to blame aswell. Anyone else experienced this and if so did you find another way to deal with s.a.d?

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