How light affects our skin and hair

Our skin is not only our largest organ, but also one of the first recipients of light impulses due to its exposed position. For this reason, it can of course be influenced by light to a special degree - both in a positive and negative sense.

This article is intended to give you information about how our skin and thus also our hair react to light and how you can use this knowledge specifically to do them some good with red light therapy or even counteract skin and hair problems.

Light consists of a composition of different light wavelengths, e.g. red light, near-infrared light (NIR), blue light, UV light, etc. (see also the article "This is the role light plays in our health"). When the different light waves hit our skin, some wavelengths are able to penetrate deeper than others. For example, while yellow, green and also blue light only reach the upper layers of the skin, long-wave red and near-infrared light can also reach deeper layers.

Wavelengths (nm)	Colour spectrum
150 - 380	UV
390 - 470	Violet - Dark Blue
475 - 545	Blue - Green
545 - 600	Yellow - Orange
600 - 650	Red
780 - 940	Dark red - NIR
940 - 1100	NIR

Regardless of the depth of exposure, different wavelengths of light also have different effects on our organism, each influencing different processes in the body:

UV rays, or more precisely the UVB rays they contain, promote vitamin D production in our skin, for example, but can also cause sunburn and premature ageing of the skin if consumed in excess. Anyone who has ever had a sunburn, and that is usually the vast majority, has therefore already witnessed for themselves how great the influence of light can be on our organism.

How red and near-infrared light affects our skin

Not all effects of light are as obvious as those of sunburn. Nevertheless, the reactions of other wavelengths of light on our bodies are usually no less significant; they are often just less well known and thus not directly associated with many symptoms.

To understand the influence of red and near-infrared light on our skin, a short excursion into cell biology is needed; but don't worry, we'll try to keep it as short and descriptive as possible:

Ultimately, our body is a collection of countless cells that fulfil different functions depending on the cell type (e.g. bone cell, nerve cell, skin cell, etc.). The power plants of the cells that produce and provide the energy needed for all bodily functions - from breathing to thinking to lifting a barbell - are called mitochondria. Scientists have now discovered that red and near-infrared light, among other things, stimulates the energy production of these mitochondria.

This is particularly interesting because a large number of recent studies indicate that our mitochondria play an important role in our overall health and the prevention of disease.

For our skin, increased energy production in the mitochondria of our skin cells means accelerated cell division. And the faster cells can divide and thus renew themselves, the faster old and damaged cells can be replaced. In other words, the repair of damaged cell tissue is accelerated and skin ageing is thus slowed down.

Since the cause of many skin problems is ultimately to be found in the damage to the respective cells, the areas of application in which red light and NIR show a positive effect are also very numerous: they range from the treatment of acne, cellulite, pigment disorders, burns, psoriasis, herpes, scar and wound healing to the treatment of UV-induced skin ageing.

Range of action of red light

The extraordinary thing about all these modes of action: Red light and NIR not only seem to have a preventive effect, but have also been proven to counteract and thus reverse damage and signs of ageing in the skin. This all sounds too good to be true? It is! And yet all this can be explained quite naturally by our body's symbiosis with nature.

So what does this mean for our hair?

Our hair, whose roots reach into deep layers of the skin, also consists of cells. These are produced at the bottom of the hair root, attach themselves to the existing hair and push it further and further out of the skin.

The lifespan of a hair, also called the hair cycle, is divided into 3 phases: In the first anagen phase, the actual hair growth takes place. In this phase, new cells are formed that make the hair longer and thicker. This phase can last for several years. Afterwards, a transitional phase begins, the catagen phase, in which the supply of nutrients is interrupted, the hair root shortens and the hair atrophies. In the telogen phase, the old hair falls out and the hair root prepares for a new anagen phase.

In people with hair loss, the cause can affect different stages of hair growth. For example, the first anagen phase/growth phase of the hair may be shortened or the second catagen phase may begin prematurely. The transition back from the telogen to the anagen phase may also be disturbed, which means that the shortened hair root does not build up again to grow a new hair.

Studies have now shown that red light/near infrared light can delay the first anagen phase/growth phase of the hair and also increase the growth rate in this first phase. It has also been shown that red light/NIR supports the transition from the third phase back to the first phase.

One suspects the reason for these positive effects in various mechanisms that are favoured by red light/near infrared light: On the one hand, the anti-inflammatory effect of red light/NIR could contribute to these effects, on the other hand, the improved energy production in the cells especially in this part of the body could also play a role. In addition, the nutrient supply of the hair root could benefit from the increased blood circulation caused by red light/NIR, or the influence of red light/NIR on the nitrogen balance in the body could explain these effects, or an interplay of all these factors.

Red light for your skin & hair

Certain wavelengths in the red light spectrum can be used to counteract a deficit of natural red light and NIR.

So if you don't regularly make it out into the sun at the red-light-dominant times of day (i.e. mainly in the morning and evening), you can treat your body to an extra portion of red light with a red-light lamp and promote all the positive properties that have been attributed to photobiomodulation by numerous studies in the meantime. So that those of us who are always busy can also get the benevolent rays that nature has provided for us.

References:

AVCI, P.; GUPTA, G.K.; CLARK, J.; WIKONKAL, N.; HAMBLIN, M.R. (2013): Low-level laser (light) therapy (LLLT) for treatment of hair loss. Lasers Surg Med. 2014 Feb;46(2):144-51. doi: 10.1002/lsm.22170. epub 2013 Aug 23. PMID: 23970445; PMCID: PMC3944668.
WHITTEN, Ari (2018): The Ultimate Guide to Red Light Therapy. Archangel Ink.
WUNSCH, Alexander (2019): The power of light. Why we need light and bad light makes us sick. 1st edition. riva: Munich.
WUNSCH, Alexander; MATUSCHKA, Karsten (2014): A Controlled Trial to Determine the Efficacy of Red and Near-Infrared Light Treatment in Patient Satisfaction, Reduction of Fine Lines, Wrinkles, Skin Roughness, and Intradermal Collagen Density Increase. In: Photomedicine and Laser Surgery. Volume 32, Number 2, Heidelberg: Mary Ann Liebert. 93-100.