Optimal Non-Contact Treatments: What Distance to Use Red Light Panels? Part 2
What is the proper distance to use Red Light Therapy Panels? More importantly, what types of treatments are appropriate for non-contact treatment? How can we optimize and improve treatments based on clinical research?
Two Types of Red Light Therapy Treatment:
The skin contact method is typically preferred in clinical studies as delivering superior absorption and penetration.
However, in many cases the non-contact method is more convenient and sufficient to deliver benefits despite its shallow penetration and high reflection losses.
As with any medicine, the goal is to find the "minimum effective dose". And non-contact treatment can certainly deliver minimal doses even though it is more superficial and delivers less photon absorption.
Yet, we need to dig deeper into the published literature to see what the real advantages of non-contact treatment could be, the types of treatments and benefits it delivers, and how we can dose it properly with at-home panels.
Advantages of Non-Contact Red Light Therapy (at a distance):
We found a handful of non-contact red light therapy studies, such that we can actually learn the proper contexts to use it. Here are a few of the advantages.
- Hands-Free: Non-contact devices generally do not require the doctor or patient to hold the device to the skin. They are usually “hands-free” and offer a convenient way to administer red light therapy, and not require the added time or cost of a clinician holding the device. Although many modern contact devices use straps and Velcro to hold it in place and be hands-free also.
- Large Areas Covered: All of the full-body light therapy studies are considered to be non-contact light therapy. Even in full body beds, the user is laying on a piece of plastic separating them from the LEDs. Large devices can get heavy and bulky, so it is generally easier to do full body treatment as non-contact method. There are zero studies that use contact-method for full body red light therapy, as it is likely impractical and unnecessary.
- Sanitation: Non-contact treatment may be preferred for sanitary reasons especially when treating multiple people with the same device. This is important for clinics that want to treat high volumes of people, and to avoid contamination.  Although many contact devices may use a clear plastic film and/or implement good cleaning practices, but this is extra work for the clinician.
Therapeutic Applications of Non-Contact Treatment:
- Superficial Treatments:
- Skincare: Since non-contact therapy is inherently superficial due to the lack of penetration, then it is typically sufficient for skincare benefits. Here are 4 studies we found that used Red and NIR LED light therapy for various skincare conditions like skin rejuvenation, improving melasma, and treating psoriasis; all with non-contact treatment.[3-6]
- Wound and Skin Ulcer Healing: Likewise wounds and ulcers that are at the surface of the skin are ideal for superficial non-contact treatment. Especially as we mentioned non-contact treatment is ideal for sanitary reasons. Here are 4 studies we found that used non-contact LED light therapy treatments for open wounds or skin ulcers. [7-10]
- Systemic Therapy: When covering large areas of the body or full-body light therapy, the goal is usually systemic benefits rather than direct penetration targeting the actual pathology. Recent theories explain this by absorption into the cell-free mitochondria found in the blood. This can benefit systems deeper in the body despite the lack of direct photon penetration.
- Athletic Recovery: Many full-body non-contact studies are conducted on athletes for recovery, as well it is known to be used by Olympic athletes. Clearly athletes need whole-body recovery in a convenient form, so non-contact therapy can be used.
- Sleep: Several full-body red light therapy studies on athletes showed an improvement on sleep metrics as well.
- Fibromyalgia: A recent full-body red light therapy study was successfully conducted on Fibromyalgia patients.
- Mood and Well-Being: A recent study with a small non-contact 850nm LED panel and only 5mW/cm^2 found an improvement in mood and general well-being, but no impact on sleep.
- Eye Care: Eye health studies are non-contact treatments, since impacting a device onto the eyeball would be dangerous and excessive. The eye does not have any skin barrier (when the eyelid is open), so the skin reflection issues we discuss are not a problem.
- Cellulite and Workouts: Several studies utilized non-contact LED therapy aimed at the thighs while the patient was on a treadmill to help reduce cellulite and improve athletic performance and recovery. [11,12] The studies used 31-39 mW/cm^2 for 30-45min while the user is exercising on a treadmill. So perhaps there is some clinically-relevant merit to exercising in front of red light therapy panels!
- Thermal management: LED and Laser devices can heat up due to natural inefficiencies with electronics. When they are used on the body, the user can experience the combined heat effects from the intensity of the light in addition to the heat of the device. This is why we put so much emphasis on measuring the heat from flexible pads in a previous review. Non-contact treatment can eliminate the concerns of heat from the device, but still too much intensity from non-contact panels can be a problem for overheating the skin.
- Biphasic Response: Skin-contact treatment delivers much more penetration and absorption than the typical non-contact panels on the market. Non-contact treatment can avoid overdosing to the biphasic dose response because it is poorly absorbed and superficial. Essentially, the non-contact method is a way of "poke-yoke" (mistake proofing) to prevent overexposure especially for home-usage. But that is assuming the intensity is sufficiently low enough to not overheat the skin to damage it. 
- More Natural? Humans have naturally evolved to be protected from non-contact light exposure from sunlight and fire. Non-contact treatment is more the "natural" way humans have been exposed to red and near infrared from the environment. This again is a mechanism for how the skin prevents overdose from non-contact treatment, similar to eating a "whole food" for nutrition instead of concentrated supplements.
- Eye and wound treatments: It bears stating the obvious that devices should not be pressed into the eyes or into open wounds. Studies conducted on human eyes are all non-contact since you don't want to scratch your cornea by shoving a device directly onto your eyeball. As well there could be pain, re-opening the wound, or infection risks with slamming a device onto an open wound.
Skin Cream for Better Absorption
One non-contact treatment study mentions using a skin moisturizer to improve light absorption. They note that dry skin can have higher reflection losses.
"To maximize LED photoinduction, a topical moisturizer without active ingredients was applied daily, as dry skin is known to enhance skin surface reflectivity (Friedman et al., 2002)." 
This may explain other studies that used a green tea application before treatment.  Perhaps the moisturizing effect was the reason for the better effectiveness, in addition to the antioxidant effect.
Unfortunately the study does not specify the "topical moisturizer" used, only that it did not have any "active ingredients".
Looking up the Friedman et al study and we found they were using EMLA cream, which was cleaned off immediately before treatment. But EMLA cream is an anesthetic cream, containing lidocaine and prilocaine. So perhaps we need to find something similar without those active ingredients.
It would seem that any moisturizing cream without additives could be helpful in this endeavour, and that the consumer can resist the marketing of special creams from clever salespeople looking to make a couple extra bucks to "enhance" red light therapy absorption.
Intensity exposure is key, Distance is arbitrary.
There is nothing magical about distances like 4 inches, 6 inches, 12 inches, or even 10cm, 15cm, or 20cm. These are convenient distances that the general population will recognize. It has nothing to do with clinical relevance.
The key is to find the correct distance in accordance with the intensity that you want the skin to be exposed to. As every brand and LED panel will be different in terms of the power consumption, number of LEDs, beam angle, LED layout and spacing, etc – then we shouldn’t always use arbitrary distances like “6 inches” for all devices on the market.
For example, if a full-body light therapy pod uses 28mW/cm^2 for 20 minutes to treat fibromyalgia. Then to reproduce those results with a panel you need to find the correct distance that corresponds to that exact intensity.
For example our OverClocked panel would deliver this ideal intensity at about 18 inches away. For super high intensity panels from our competitors, the distance could be much further away, assuming they give honest and accurate intensity measurements for their product in the first place.
Exposing the skin to higher intensities than the studies does not necessarily deliver "better" or "faster" results, as the therapy must abide by a dose-rate response with adequate exposure time. And excessively high intensities >50mW/cm^2 run the risk of overheating the skin and causing deleterious effects.
Finding the correct distance for red light therapy means looking up the accurate intensity data provided by the manufacturer and choosing the correct distance in accordance with the relevant science.
Maintaining The Proper Distance
Humans can be frustratingly fidgety, which makes maintaining the proper distance from the device challenging. Here is one quote that seems to stress the problem and importance of maintaining a consistent distance to proper dosing in a wound healing study:
"During this study, a lot of care was taken to maintain a working distance of 2.5cm (±1mm) away from the target surface during LED therapy, as power density/light intensity—a key variable for optimal photoinduction—is greatly influenced by the distance between the light source and the surface of the skin (Hart and Cameron, 2005). " 
This seems to be another deterrent from using non-contact red light therapy in clinical studies. Where the preference is just to hold a device on the skin to maintain a consistent dose. The logistical issues of keeping the distance exactly the same for the duration of the treatment will lead to inconsistent dosing, and make it difficult to design clinical trials.
We were able to find a handful of actual studies that used non-contact LED Red & NIR light therapy to help inform us how to optimize treatments with LED panels. It is important to look at studies that use relevant devices to the types of panels we see on the market to learn how to properly use them.
There is a common theme that non-contact treatment is used for superficial treatments and systemic therapy, rather than direct deep penetration targets. This is consistent with our understanding that non-contact treatment has poorer penetration.
Studies that are non-contact include eye health, wound healing, skin ulcer healing, skincare, cellulite, fibromayalgia, sleep, and athletic performance and recovery. Many of which are superficial or systemic in nature, which seems clear the researchers understand that non-contact therapy is appropriate mostly for superficial applications.
There are obvious advantages to non-contact LED light therapy treatments like convenience, being hands-free, covering large areas of the body comfortably, reducing heat exposure from devices, reducing contamination, and reducing the likelihood of overdosing especially for new users at home.
As always, users should be aware of all their options for therapeutic treatment, understand the pro's and con's of different types of treatment, learn the real science, and utilize honestly advertised devices responsibly.
Hopefully more studies on non-contact red light therapy will be conducted to futher our understanding of this mode of therapy. But we need to be clear-minded about the true nature of non-contact treatment and how the mechanisms and targets are different than therapeutic skin-contact treatment.
Navarro-Ledesma S, Gonzalez-Muñoz A, Carroll J, Burton P. Short- and long-term effects of whole-body photobiomodulation on pain, functionality, tissue quality, central sensitisation and psychological factors in a population suffering from fibromyalgia: protocol for a triple-blinded randomised clinical trial. Therapeutic Advances in Chronic Disease. 2022;13. doi:10.1177/20406223221078095