Is Pulsing Effective in Red Light Therapy?

Red light therapy is a gentle technique, involving low-level red light wavelengths that can either pulse or remain steady, aimed at improving our cells’ functionality and, in turn, our health in various ways.

The buzz around red light therapy and pulsing has surged, offering everything from belts to panels and smaller devices to cater to a wide range of user needs.

While sifting through the multitude of options, including those topping the "best of" lists in 2024, it’s crucial for users to weigh their specific needs against available scientific data and any potential downsides. We here at RLT Home have designed full body red light therapy panels with 7 wavelengths including blue and orange along with 5 red and NIR wavelengths and custom pulsing. 

What Is Pulsing In Red Light Therapy?

Pulsing is the intentional use of short bursts of light rather than a steady application of continuous light.

The frequency of pulsing is measured in Hertz (Hz), which means cycles per second. If light pulses 10 times per second, it would be measured as 10 Hz.

Pulsing is typically administered in a 50:50 ratio, meaning that the pulses of light and intermittent pulses of “off-time” are equal in duration. Because the light is off as much as it is on, the intensity of pulsing light will only be half that of continuous light.

How is Pulsing Different From Light Flicker?

Pulsing is intentional whereas flicker is not. Flicker is random, not consistent in intervals like pulsing.

Light flicker is an intrinsic result of alternating current (AC) power, which red light therapy panels run on.

Although flicker is an inevitable by-product of AC, it is undesirable in red light therapy devices. Manufacturers strive to achieve the lowest possible flicker percentages (level to which light dims in a flicker) and frequencies (number of times per second light flickers) in their devices. It is interesting, then, that intentional pulsing has grown in popularity as an option in some newer red light therapy devices.

Is Pulsing Effective in Red Light Therapy?

Some studies have suggested that pulsing light can be more effective than continuous light for certain applications, while others have found no significant difference.

There's no concrete evidence to prove that pulsing is effective in red light therapy for healing, anti-aging, pain relief, fat burn, muscle growth, facial skin rejuvenation or the many other goals of typical users.

However, it has been found to be useful for:

Deeper Tissue Penetration: Pulsed light may penetrate deeper into tissues than continuous wave light, potentially reaching deeper-seated injuries or areas of inflammation.

Reduced Heat Production: Pulsing the light can reduce the overall heat produced, which can be beneficial if avoiding heat is a concern.

Cellular Response: Some research suggests that cells might respond differently to pulsed light compared to continuous light, potentially leading to different therapeutic outcomes.

The healing and rejuvenating powers of red light therapy rely upon a steady projection of light onto your skin. Because pulsing light is only half as intense as continuous light, it will only provide half the cell penetration and half the therapeutic results.

When and Why Did Pulsing Become a Trend in Red Light Therapy?

A study to determine the most effective applications for laser light therapy (published in 2010) was performed by a professor at Harvard University. The study compared treatments using continuous and pulsed waves and found that pulsed light consistently yielded better therapeutic results.

Those results sparked the idea that pulsing would be the better method of therapy with all light forms. That study, however, only experimented with laser light, not light-emitting diodes (LEDs). At that time, laser light was the predominant method of therapy. Red LED light therapy as we know it today was still in its developmental stages.

It is not entirely correct to assume that the findings of a study utilizing only lasers would automatically also apply to LEDs as both have different characteristics and that may lead to different results.

Red LED Light Therapy Versus Laser Therapy

An LED is a semiconducting device that emits visible light when an electric current passes through it. LEDs produce incoherent light, which means that they do not produce any significant heat. LEDs penetrate your body without damaging or burning it.

A laser, on the other hand, produces coherent light. This means that it generates a lot of heat and is far brighter and more intense than LED light. Laser light is capable of heating and burning your skin and damaging your internal organs. The primary reason for pulsing in laser treatments is to mitigate these safety risks. Pulsing allows your skin brief periods during which to cool off.

In red LED light therapy, no such heat mitigation is necessary. You might experience a mild and pleasant warm sensation on your skin during therapy, but you will not burn. Red LED and NIR (near-infrared) light therapy can now provide the same depth of cell penetration and healing as older laser technology but without the dangers.

As LED technology began to surpass laser therapy in popularity, LEDs were viewed as a replacement for lasers in light treatment. This is why, even though an LED is not a laser, red light therapy as we know it today is sometimes also referred to as low-level laser therapy.

Is Pulsing With a Red Light Therapy Device Good for Anything?

Although the role of pulsing is unclear in the red light therapy applications typically sought by users, there is evidence that it may be effective in “brainwave entrainment”, or the ability of the neurons in your brain to synchronize with light and sound frequencies around you.

Studies show that pulsing light at certain frequencies on alpha and gamma brainwaves can provide brain-entraining properties that may be useful in treating degenerative diseases such as Parkinson’s and Alzheimer’s. The brain returns to a more natural and ordered state of being.

Even light flicker may have a positive impact on brain entrainment.

Brain entrainment is the only benefit of pulsing that shows any real promise in red light therapy.

Red Light Therapy Devices With Pulsing Options

Be cautious when selecting a red light therapy device for at-home use.

If a device is advertised as offering enhanced red light therapy results or providing special benefits (other than brain entrainment) due to pulsing options, be wary. The science behind red light therapy hasn't evolved fully to guarantee these claims.

The best way to choose a device is to educate yourself on the technology so you can make an informed decision.

Are There Any Side Effects Associated With Pulsing?

Pulsing is an unnatural stimulus for your brain and can cause an imbalance in brain-cell activity with unpleasant symptoms:

• nausea
• dizziness
• rapid eye movements
• headaches
• disorientation
• in extreme cases, seizures (especially in anyone who suffers from epilepsy)

Pulsing is best avoided unless used for brain entrainment purposes, in which case it should be administered with the utmost care and diligence to avoid causing distress.

Scientific Support

The first study linked here is the original research that first sparked the pulsing trend in red light therapy. [1]

The second and third studies illustrate that pulsing LED light might be beneficial when limited to the application of brainwave entrainment. [2][3]

The fourth link simply provides a more detailed explanation of the difference between LEDs and lasers for those interested in the science behind these technologies.[4]

• nih.gov – Pulsing in Low-Level Light Therapy (opens in a new tab)
• sciencedaily.com – Flickering & Alzheimer’s (opens in a new tab)
• nih.gov – Pulsed RLT Modulates Neural Oscillations (opens in a new tab)
• electronicscoach.com – LED and LASER Difference (opens in a new tab)

In conclusion, pulsing in red light therapy may add to its therapeutic benefits. Research is ongoing and we'll soon have more clarity on this subject.