What You Need to Know About Red vs. Green Light Therapy for Pain

Red vs Green Light Therapy

According to the Centers for Disease Control and Prevention (CDC), an estimated 50 million U.S. adults suffer from chronic pain. The CDC defines this as pain that people experience every day or most days over the past six months. Of those pain sufferers, nearly 20 million experience what is known as high-impact chronic pain, which is long-term (chronic) pain that severely limits life or work activities. 

In the United States, billions are spent annually on pain management, and the economic effects of lost work days and productivity cost even more. But to the person who’s suffering, it’s not about the money; it’s about the diminished quality of life, negative emotional effects, and the many potential side effects of pain-relieving drugs that have contributed to this country’s opioid epidemic. 

If you're among these chronic pain sufferers and you worry about long-term effects of prescription pain medications or over-the-counter drugs, have you ever considered light therapy? In the past few years, studies have produced some exciting findings about the use of green light to treat chronic pain, such as research by pharmacologist Mohab M. Ibrahim, M.D., who is medical director of the Chronic Pain Management Clinic at Banner - University Medical Center in Tucson, Arizona.

In this article, we’ll discuss the benefits and limitations of red light vs. green light therapy for pain, as well as why red light is considered the most  effective solution.

Current Pain Management Options

Woman in pain trying to take medication

Chronic pain is a serious condition with repercussions far beyond physical discomfort, including depression, anxiety, or sleep problems. It is highly personal, too. The cause, your biology, and even your mental state can all play a role in chronic pain, and can alter the approach you choose because what works for one patient may be ineffective for another. 

Today’s medical options include nonsteroidal anti-inflammatory drugs (NSAIDs, like aspirin and ibuprofin), COX-2 inhibitors (prescription NSAIDs), acetaminophen (Tylenol), antidepressants, anti-seizure medication, and opioid painkillers—all of which can be effective but potentially carry serious side effects, especially when used long-term.

In lieu of drugs, light therapy is gaining popularity as a way to treat pain naturally without side effects.

How Light Affects the Body

Scientists have long known that light has biological effects on humans. It has been used for millennia to treat depression, improve wound healing, and reduce inflammation. All these positive effects can lessen the perception of pain—but there’s much more to light therapy than just going out into the sunshine.

The sun is the original source of light healing, but we now know that too much of its powerful ultraviolet light carries risks, including skin damage and premature aging. The individual wavelengths of light that collectively make up what we see as white light are actually a whole spectrum of color with very specific properties and effects on the human body. These wavelengths are measured in nanometers (nm), and the two most closely tied to pain relief are green light and red light.

Green light wavelengths measure from 520nm to 560nm. Red light wavelengths measure from 620nm to 660nm, and wavelengths of near-infrared (NIR) light (often referred to as red light) measure from 820nm to 850nm.

How Green Light Helps Pain

Green light appears to have two mild pain-relieving effects: it is antinociceptive (analgesic, meaning a pain reliever) and antihyperalgesic (reduces sensitivity to input from the nervous system). However, the effects of green light on pain relief are not widely studied.

The effects of green light on the body include:

  • Resetting the circadian rhythm: photoreceptors in the eye are extremely sensitive to types of light, and when these photoreceptors are exposed to green light, it alters melatonin production to stimulate energy and alertness (perception of pain is often reduced when we are energized).
  • Green light alters serotonin levels and stimulates the endogenous opioid system (the body’s pain-relieving system present in the central and peripheral nervous systems as well as in the immune system and gastrointestinal tract).
  • Green light increases the number of pain-relieving molecules known as enkephalins.
  • Green LED light stimulates the endogenous endorphin and cannabinoid systems—the body’s own naturally produced painkillers. A follow-up human study to the animal study mentioned above is underway, but to date there is just not enough data to confirm that green light therapy for pain is effective, or not.

Green Light Research

Person getting green light therapy

To date, there is only one completed human study on green light tharpy. The challenge with green light is that its effects are only activated when the light enters through the eyes because the wavelengths are too short to absorb into the body’s tissues.

Dr. Mohab Ibrahim of the University of Arizona conducted research on the effects of green light therapy on pain in rats, and found that it produced antinociceptive (pain-blocking) and antihyperalgesic (reducing heightened sensitivity to pain) effects. 

One of the experiments involved placing green plastic eye contacts while the rats were exposed to ambient room light. On days 3 and 4, the rats developed thermal analgesia (the inability to feel heat-related pain) when their paws were exposed to heat from a high-intensity projector lamp. As a result, Dr. Ibrahim suggested that green light plays a role in activating the endogenous opioid system (the body’s own pain relief system). 

Dr. Ibrahim followed this study up with a clinical trial inspired by his own brother’s ongoing battle with severe headaches. Rather than taking over the counter painkillers, Dr. Ibrahim’s brother would sit in his garden, letting the verdant green of the garden ease his headache pain. Dr. Ibrahim wanted to confirm whether it was the green light that eased the pain, or something else.

In Dr. Ibrahim’s migraine study, 25 volunteers who suffered from migraines were exposed first to white lights (as a control), and then to green LED lights. Pain intensity and duration, frequency of headaches, pain reduction, quality of life, and other parameters were measured. The results showed fairly significant reduction in pain (initial reported baseline pain scores were 8 out of 10 with 10 being the highest. After exposure to green light, the baseline pain scores dropped to 2.8. Likewise, participants reported that their quality of life nearly doubled.

Bing Liao, M.D, neurologist at Houston Methodist Hospital, confirms that green light alters the body’s endogenous opioid system and boosts levels of serotonin.

Again, the main drawback to using green light for pain is that the light must enter through the visual system. This supports the age-old wisdom that people tend to feel better in nature, especially among trees; however, going outside is not always an option. 

Handheld or lamp-style green light devices can be used at home, but the therapy must be administered with green light as the only light source. Green light therapy times can last for 30 minutes to several hours. For migraine sufferers, this can be a wonderfully soothing time of relief from harsh light. However, for people who have trouble seeing in dimly lit spaces (and want to keep busy during the treatment), this can be a big time commitment.

How Red Light Helps Pain

Compared to green light, red light offers relief from a wider range of conditions, including osteoarthritis, low back pain, or muscle injury. Red light therapy is more easily administered (it does not need to be the only light source), treatment sessions are shorter, and red light has been clinically proven to treat many different types of pain.

Red light is most often used for painful surface conditions such as chronic skin disorders, while near-infrared light is able to penetrate deep into muscles, joints, and even into the brain to support natural healing.

At the root of all of these differences is the fact that red light addresses pain in a different way than the soothing effects of green light on the brain.

Unlike green light, the effects of red light have nothing to do with the sensory (visual) system. Rather, red and NIR light wavelengths absorb into the skin and stimulate mitochondria, which are the “energy factories” of cells. This results in two important processes: increased cellular energy, and reduced inflammation.

Woman getting red light therapy

Increased Cellular Energy

Mitochondrial dysfunction, or low cellular energy, is a significant cause of painful conditions including peripheral neuropathy (which can manifest as severe, stabbing pain), fibromyalgia, and muscle pain not related to injury or exercise. The mitochondria are the energy centers within each cell: and cells don’t function at their best when they’re low on energy. 

Red light stimulates production of this energy in the form of adenosine triphosphate (ATP). As cells get more energy, they are better able to perform their functions. This effect goes beyond the cells that are directly irradiated by red and near-infrared light, since all bodily systems are interrelated. As one system starts to function better, it positively influences other systems.

Reduced Inflammation

Chronic inflammation wreaks havoc on the body. Chronically inflamed cells are literally fighting for survival and can’t do their jobs properly. But there’s more to it: When an area of the body is inflamed, chemicals such as histamine and bradykinin leak into the tissues, painfully overstimulating the nerves. 

A 2017 study led by noted red light therapy expert Michael R. Hamblin focused on red light therapy’s ability to reduce inflammation. The study noted that several animal models found that red light promotes faster wound healing; reduction in joint inflammation; reduction of oxidative stress in muscles; and neuropathic pain. In human trials, too, red light appears to have powerful anti-inflammatory properties. 

This reduction in inflammation could reduce the leakage of histamine and bradykinin, and therefore reduce pain.

Other Pain-Relieving Therapeutic Effects of Red Light

Through thousands of studies, red light therapy has been clinically proven to spark a positive ripple effect of biological processes that reduce pain.

  • Red light can support liver regeneration, which will help your body rid itself of toxins and can reduce systemic inflammation
  • Red light reduces oxidative stress, which has been linked to depression and anxiety (both of which increase the perception of pain)
  • Red light reduces neuropathic pain and promotes nerve regeneration
  • Red light stimulates healing of skin wounds by reducing inflammation, increasing blood flow, and stimulating collagen synthesis
  • Red light increases blood flow by stimulating the production of capillaries, which move more oxygen and nutrients to an affected area, and remove waste products that could be causing inflammation
  • Red light stimulates production of stem cells. These “master cells” are part of the immune system; normally in a dormant non-specialized state, they only spring into action when they are needed, taking on a variety of specialized roles to assist with healing
  • Red light therapy has been used successfully to treat chronic low back pain and osteoarthritis pain, which affect a significant portion of the U.S. population (65 million and 27 million, respectively).

What About Migraine Pain?

Man with Migraine

The big question for migraine sufferers with photophobia (migraines triggered by exposure to light, including red wavelengths) is: “How can red light therapy possibly help my migraine if it hurts to look at it?”

The answer is: You can still use red wavelengths to treat the underlying causes of migraines... just don’t look at the device. Use the light-blocking goggles, close your eyes, relax, and let the red and near-infrared waves absorb into the body’s tissues (not into your eyes), where they can ease the inflammation that could potentially be a cause or contributing factor to a migraine. 

Migraines can also be caused by hormonal, medicinal, environmental, dietary, or emotional, factors—and red light can treat some or all of these, to potentially help eliminate the root causes of migraines.

Managing Pain with Green Light or Red Light: Which Is Better?

So, which is better overall at managing pain: red light, or green light? 

For most conditions, the answer appears to be red light since only one study has been conducted on green light. Red/near-infrared light has much deeper penetration than green light, and red light isn’t limited to entering the body through the visual system. 

Green light can be used to relieve migraines, by sitting in a darkened room illuminated only by green light with the eyes open. Other types of pain, especially in areas of the body not connected to the visual system, respond extremely well to red light. 

Red light is more than soothing. It effectively treats two primary causes of chronic pain: mitochondrial dysfunction and chronic inflammation.

Experience Chronic Pain Relief with Red Light Therapy

To get effective relief, be sure to use quality LED panels that deliver the highest possible irradiation (light energy output) for optimal absorption of beneficial red/near-infrared light into the body’s tissues. 

  • The PlatinumLED BIO series are powerful panels where you can choose to use purely red light (660nm), NIR light (850nm) or a combination of both in a 1:1 ratio. 
  • The PlatinumLED BIOMAX series offers superior irradiation and a full-spectrum combination array using a patented combination of the most scientifically validated red/near infrared wavelengths.

Unlike medications that mask the pain by alleviating symptoms, red light therapy addresses the underlying causes. It can take a little time, but the results will be worth it as you experience relief and regain your quality of life.

For more on how red light therapy can boost your health, check out the large collection of articles on the PlatinumLED blog.