If you've ever attended a class on product formulations and ingredients, you know that there are many different pathways through which specific ingredients work. To some extent, LED light therapy is the same. Much like product ingredients, various wavelengths of light interact with cellular processes to stimulate a physiological response. Just as it’s important to know which ingredients are most appropriately used on a particular skin condition, it’s also useful to have some fundamental knowledge as to how various wavelengths work, and the benefits with which they are associated.
Wavelength refers to the distance between each peak or crest of a wave of light, heat, or other energy, and the next corresponding peak or crest. In Figure 1., you can see the short distance between peaks on the left side of the diagram as opposed to the relatively long distance between peaks on the right. Generally speaking, the shorter the wavelength, the higher the energy. Although longer wavelengths have lower energy, up to a point, they have the ability to penetrate more deeply into skin and body tissue. In the centre of this image is the visible light or the light we can see. On either side of the visible light is energy that cannot be seen. Daylight, as you may recall from a long-ago science class, is a combination of electromagnetic energy that is both seen and unseen. In order to view the colours of daylight or white light individually, they must be separated through something that creates a bend, such as a prism or droplet of water. This is how we see rainbows.
Wavelengths are measured in what we call nanometers, as seen in Figure 2. A nanometer (nm) is equal to one billionth of a meter. In skincare, we’re mostly concerned with the 400-nanometer range seen as blue, the 600 to 700-nanometer range seen as amber and red, and the 800 to mid 900-nanometer range that we cannot see. Light in this range falls into the infrared category and is beyond the visible spectrum.
Of primary concern is getting enough light energy to what is known as “target chromophores.” A chromophore is essentially a molecule that has the ability to absorb light. In order for there to be any physiological response to light treatment, the cell must absorb an adequate amount of energy. In theory, a single photon (or packet of light energy) can activate a cell, but in practice, it requires multiple photon absorption to raise the action potential of a cell. This is not to say the more powerful the device, the more effective the treatment. In fact, too much light energy density can actually diminish effects. This is referred to as a biphasic dose response. According to experts in the field of low-level light therapy, the only way to accurately determine whether or not a device is delivering a sufficient amount of energy is to observe consistently positive results over an extended period of time. It’s also important to note that different wavelengths are preferentially absorbed by different chromophores in the body. For example, blue is absorbed by certain light-absorbing molecules in the body, and red by others.
Doing Your Level Best
To understand why certain wavelengths or colours are used to treat specific conditions, let’s revisit a couple of points. Shorter wavelengths have more energy, and more energy generally means less penetration. Wavelengths in the blue range (shorter wavelengths) only penetrate tissue to the level of the epidermis, approximately 1 mm in depth. Blue is used to treat acne because the depth of penetration for this range allows us to hit p. acne bacteria where it lives. As it happens, blue wavelengths are also absorbed by specific chromophores known as coproporphyrin III, and protoporphyrin IV, present in p. acne bacteria. Absorption by these chromophores triggers a photobiochemical reaction essentially causing the bacteria to self-destruct.
Amber and red, being longer wavelengths with lower energy and deeper penetration, are mostly absorbed at the level of the dermis, approximately 1.5 – 2.3 mm in depth. For this reason, amber and red are often used to stimulate mitochondrial activity within the fibroblasts, thereby encouraging the production of proteins like collagen and elastin necessary for plumping and firming the skin.
Longer still, near-infrared wavelengths penetrate even more deeply to approximately 4mm and greater allowing them access to the level of subcutaneous and muscle tissue where they promote increased blood circulation and reduce pain and inflammation. They are known to diminish swelling and bruising and promote wound healing. Wavelengths in this range are often combined with red and used post-procedures such as micro-needling, injectables, laser, and surgery. The primary chromophore for absorption of red and infrared wavelengths is known as cytochrome c oxidase, an enzyme that is part of the electron transport chain where cellular respiration takes place.
Casting a Wider Net
Since LED or low-level light can be absorbed not only by fibroblasts but by many different cell types in the body including immune cells, the possibilities for light-mediated effects that help boost the body’s natural ability to protect and repair are widespread. Although it is generally agreed upon that there are certain ranges that have the most therapeutic value, studies demonstrate positive effects as a result of using different wavelengths within these ranges of red and infrared. According to a study conducted by Harvard Medical School’s Wellman Center for Photomedicine, “Wavelengths in the 600 – 700 nm range are used for treating superficial tissue, and wavelengths between 780 – 950 are chosen for deeper-seated tissues due to longer optical penetration distances through tissue. Wavelengths between 700 – 770 nm are not considered to have much activity. Some devices combine a red wavelength with a NIR wavelength on the basis that the combination of two wavelengths can have additive effects, and can also allow the device to be more broadly utilized.” One may conclude from this that if you cast a wider net by utilizing multiple wavelengths within the clinically proven ranges, you are far more likely to affect positive change. Devices that combine wavelengths delivered simultaneously are not common, but they do exist.
Treating With LED & LightStim
Without a doubt, the more sophisticated our options become, the greater the necessity to understand how they work. This is critical not only to ensure you use your resources effectively but also to provide insight into how to integrate treatments for the best possible results. Let’s consider some possibilities for integrating LED with other treatments. Below are some examples of protocols that should, of course, be customized depending upon skin type and condition. Many consumable product manufacturers have specific LED treatment protocols, and it's recommended that you check with them for detailed instructions.
LED For Acne
- Exfoliate & Steam - enzymes are a great option for eliminating keratolytic buildup
- Consider an oxygen-based treatment here – oxygen will help diminish bacteria
- Apply serum – options may include anti-bacterial, antioxidant, and anti-inflammatory ingredients
- LED treatment – blue to destroy bacteria and red to reduce inflammation
- Apply moisturizer and sun protection
LED For Healthier, More Radiant Skin
- Exfoliate – this may be done with enzymes, microdermabrasion, or some peel treatments. How soon after a peel can you use LED? This depends on specific ingredients, strength and pH. LED treatment may generate some mild warmth in the skin. Consult with your peel manufacturer for timing recommendations.
- Apply serum – options may include collagen boosters, cell stimulators, antioxidants, anti-inflammatories, and hydrators
- LED treatment – amber, red & infrared are all beneficial to trigger desirable cellular responses
- Masque – apply appropriate masque for skin type if desired (transparent masques may be used over serum prior to LED treatment – check with device manufacturer)
- Perform massage and remove excess product with a warm towel
- Apply additional serums as necessary, moisturizer and sun protection
LED & Massage Therapy (for pain & healing)
- Client to arrive with clean skin
- Possible add-ons – hot towels, body exfoliation, wraps, topical pain or body rejuvenation products
- LED treatment – red & infrared to stimulate blood flow, soften and release tissue in areas of difficulty (i.e. trigger points or myofascial restrictions) and relieve pain & inflammation
- Perform massage treatment
- Remove any residual product