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Treating SAD And Acne At The Same Time

By Megan Griffith

Reviewed for medical accuracy by Dr. Jaggi Rao,
MD, FRCPC Double board-certified dermatologist

November is the time of year that many people in the Northern Hemisphere start to get the blahs. In North America, especially in the United States, people tend to get pre-holiday depression, but all over the Northern Hemisphere many people start to get SAD, or seasonal affective disorder. And making their depression worse, late autumn and early winter are also the time of year acne gets worse.

SAD is a kind of depression with fatigue that sets in as the days get shorter, especially just after the switch off daylight savings time. People who have SAD want to sleep more1, on average about 2-1/2 hours a night more. They have trouble getting up in the morning. They eat more, especially sugar, and they withdraw from friends and family.

Blue Light Therapy for Acne and SAD
Blue light therapy can help treat acne, but can also help those who are suffering from seasonal affective disorder.

The symptoms of SAD are most common in the late autumn and early winter months when there is the least sunshine, but people who work in windowless offices or who live in basement apartments can develop the condition any time of year. SAD is consider “major” depression, and can cause symptoms that just as serious as major depression of any other cause.

The Biological Basis Of SAD

Physiologists have determined that people who get SAD have a different kind of brain chemistry with regard to the sleep hormone melatonin2. Melatonin is the hormone that makes us sleepy. The brain makes melatonin during sleep provided the eyes do not sense blue light. Even a night light, even when the eyelids are closed, can emit enough blue light to interfere with the production of melatonin for most people. Sufferers of SAD, however, are not as sensitive to dim blue light.

People don’t get SAD unless they sleep in dark rooms—but when they do, their brains make so much melatonin that they feel tired and depressed all day long. The effects of SAD are similar to those caused by taking supplemental melatonin during the day, only they are more severe. Brain scientists have observed that the pineal gland (which makes melatonin) can become enlarged due to overactivity during the early winter in people who have SAD.

Treating SAD With Blue Light

The standard treatment for SAD is blue light to interrupt the production of melatonin3. Strong sunlight includes some blue light and helps SAD sufferers wake up in the morning. Of course, most people who have seasonal depression don’t live in places where there is a lot of sunshine, so they need to use lamps and light boxes.

Doctors used to think that more would be better for blue light therapy. Light boxes delivering nearly as much light as standing under a spotlight were designed for depression treatment. Clinical experiments have found, however, that the best intensity of blue light for treating SAD is 550 lux, or about the same intensity as good office lighting. It takes two to three hours exposure to blue light—with eyes open—to help counteract the condition.

Treating Acne With Blue Light

Blue light is not just used to treat the wintertime blues. It is also used to4 treat acne. Acne bacteria contain a pigment known as a porphyrin that resonates when it is exposed to visible blue light. The pigment vibrates and breaks the cell membrane and the bacterium dies, usually within 48 hours. Blue light rays reach through the skin down to the level of pores, but they do not reach the bloodstream or the oil-producing sebaceous glands where acne bacteria can also reside. Blue light treatment kills enough acne bacteria5 to reduce the number of blemishes but it will not make acne-prone skin blemish-free.

Since blue light treats the seasonal affective disorder and blue light treats acne, if you have both the wintertime blues and acne could you treat both conditions at the same time? The answer is “maybe.”

The brain responds to blue light concentrated at a wavelength of 464 nanometers. Acne bacteria respond to blue light concentrated at a wavelength of 415 nanometers. A light box for SAD will not help your acne and a blue light lamp for your acne will not help your depression. Blue light that is the right frequency for treating depression is not at the right frequency for treating acne—unless you use “enhanced” blue light therapy.

Enhanced Blue Light Therapy For Seasonal Affective Disorder And Acne

Enhanced blue light therapy provides the full range of visible light in sunlight plus an extra dose of blue light in the frequencies that can treat both depression and acne. It does not include the UV rays that can potentially damage the skin. Technically, the intensity of enhanced blue light cannot be measured in lux so direct comparisons to other treatment systems are not possible, but the energy emitted by enhanced blue light therapy is about 1/20 as much as the energy used in the “light box” systems used to treat seasonal affective disorder. Enhanced blue light therapy provides enough light to stop depression but no so much light that the system causes glare.

The light from enhanced blue light therapy is strong enough to treat both conditions, but it is essential (1) that eyes are open so that the brain “resets” to stop depression and (2) acne-prone skin is exposed to the light to kill acne bacteria. Since enhanced blue light therapy lamps also generate red light, they can help stop excess oil production deeper in the skin at the same time they kill acne bacteria in pores.

When you are using blue and/or red light therapy for treating acne, it is important to remember that more is not necessarily better. The inflammation caused by acne, unlike the inflammation caused by impetigo and some other kinds of skin infections, is not generated by the bacteria themselves. It is generated by the immune system6. Your objective is just to kill enough acne bacteria that your immune system does not stay on high alert trying to get rid of this usually harmless skin infection.

Likewise, with red light therapy, your objective is not to “dry out” the skin. It is only necessary to reduce excessive sebum production7 in the oil glands of the skin to keep blemishes smaller. But light therapy is just part of the process of getting rid of acne for good.

There’s just no way you can get rid of acne blemishes without a good daily cleansing routine8. You may also benefit from exfoliant skin peels that keep dead skin from accumulating in pores9. And you may need treatment for brown spots left when pimples heal and a method for smoothing out small acne scars. This requires a combination of products you can find in a system like Exposed Skin Care.


  1. Melrose S. Seasonal Affective Disorder: An Overview of Assessment and Treatment Approaches. Depression Research and Treatment. 2015.
  2. Roecklein K.A., Rohan K.J. Seasonal Affective Disorder. Psychiatry. 2005;2(1):20-6.
  3. Miura J., Yuasa T., Sugai Y., Yamagami K., Aizu Y. Effects of Bright Light with Reduced Blue Light on Sleepiness on Rising: A Small Exploratory Study. Sleep Disorders. 2018.
  4. Ammad S., Gonzales M., Edwards C., Finlay A.Y., Mills C. An assessment of the efficacy of blue light phototherapy in the treatment of acne vulgaris. Journal of Cosmetic Dermatology. 2008;7(3):180-8.
  5. Fan X., Xing Y.Z., Liu L.H., Liu C., Wang D.D., Yang R.Y., Lapidoth M. Effects of 420-nm intense pulsed light in an acne animal model. Journal of the European Academy of Dermatology and Venereology. 2013;27(9):1168-71.
  6. Antiga E., Verdelli A., Bonciani D., Bonciolini V., Caproni M., Fabbri P. Acne: a new model of immune-mediated chronic inflammatory skin disease. Giornale italiano di dermatologia e venereologia. 2015;150(2):247-54.
  7. Pei S., Inamadar A.C., Adya K.A., Tsoukas M.M. Light-based therapies in acne treatment. Indian Dermatology Online Journal. 2015;6(3):145-57.
  8. Rodan K., Fields K., Majewski G., Falla T. Skincare Bootcamp: The Evolving Role of Skincare. Plastic and Reconstructive Surgery. 2016.
  9. Evaluate before you exfoliate. American Academy of Dermatology (Website). Accessed 2019.
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