What Is Pulsing in Red Light Therapy?
Pulsing in red light therapy means the light source turns on and off rapidly at a specific frequency, measured in Hertz (Hz). For example, a 10 Hz pulse means the light turns on and off ten times per second. This can be applied to both lasers and LEDs.
Why Was Pulsing Introduced?
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Lasers: Early photobiomodulation (PBM) research used pulsed lasers to prevent tissue heating and damage, since lasers can deliver very high peak powers. Pulsing allows for tissue cooling between bursts and potentially deeper penetration because of higher peak intensity.
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LEDs: Most consumer red/NIR panels use LEDs, which operate at much lower intensities and rarely pose a risk of heating tissue. The rationale for pulsing LEDs is less clear and is mostly extrapolated from laser research.
Reference: Gembared's pulsing blog post
Are There Proven Benefits of Pulsing?
The research is mixed and incomplete:
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Laser studies have occasionally shown that pulsed light (especially in neurological applications) can have different biological effects than continuous wave (CW) light. Some animal and cell studies suggest improved tissue repair, anti-inflammatory effects, or increased depth of penetration.
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LED panels: There is no clear consensus or robust clinical data showing that pulsing provides additional benefits for general wellness, skin, or musculoskeletal applications compared to continuous light.
Major review papers state that most benefits seen from pulsing have not been reproduced in large, well-controlled clinical studies—especially for LED panels.
"At this time, the use of pulsed light in LED panels remains more of a marketing claim than a proven necessity for general PBM use."
— Gembared, 2022
Popular Pulsing Frequencies and Their Theories
1. Nogier Frequencies
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Developed by Dr. Paul Nogier, these are a series of frequencies (73 Hz, 147 Hz, 294 Hz, 587 Hz, 1,170 Hz, 2,340 Hz, 4,680 Hz) believed to resonate with various tissues and systems in the body.
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Scientific reality: There is no robust evidence that these frequencies have the claimed effects on human tissue. Most research supporting Nogier frequencies is anecdotal or from non-peer-reviewed sources.
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Why do some companies use them? Mostly for marketing or to appeal to “biohacking” communities, rather than from clinical necessity.
2. Neurological Frequencies: The Case for 40 Hz
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40 Hz (Gamma frequency): This is the only pulsing frequency with significant scientific attention, especially in neurological photobiomodulation.
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Studies (e.g., by MIT and in “Nature”) have shown that 40 Hz pulsed light can entrain gamma oscillations in the brain. These oscillations are impaired in Alzheimer’s and some neurodegenerative diseases.
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Mouse studies show 40 Hz pulsed light may help clear amyloid plaques and support memory, but human data is still limited and preliminary.
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Not for general use: Most consumer panels cannot deliver focused 40 Hz PBM to the brain.
References:
The Reality Check: Pulsing in Consumer LED Panels
Technical Challenges
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Accuracy: Many panels do not output the precise pulsing frequency they claim. Third-party testing often reveals wide discrepancies or “simulated” pulsing that’s just a dimming effect, not true frequency-specific pulsing.
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Output: When LEDs pulse, the average power delivered to the tissue is reduced. For example, a 50% duty cycle means the light is off half the time, halving the average irradiance.
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Misleading claims: Companies often advertise “multi-frequency” or “Nogier” panels without independent verification that these frequencies are accurately produced or are beneficial.
Pulsing vs. Continuous Light
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For most therapeutic uses, continuous light has the strongest and most consistent evidence base.
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Pulsing may be beneficial for certain neurological conditions (i.e., 40 Hz for Alzheimer’s research), but not for general PBM applications.
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No pulsing pattern is universally recognized as superior; what works (if anything) is likely case-specific and may depend on the individual.
Physics Note: Terahertz (THz) Frequencies in Visible/NIR Light
All light already “pulses”—but not in the way most people think.
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The visible and NIR photons themselves oscillate at extremely high (terahertz) frequencies. For example:
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Red light (around 650 nm): ~460 THz (that’s 460,000,000,000,000 cycles per second)
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NIR (around 850 nm): ~350 THz
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What does this mean?
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The “pulsing” discussed in LED therapy (10-5000 Hz, for example) is enormously slower than the frequency of the light wave itself. Biological tissues interact with the energy and photon density, not the base THz frequency of the light.
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There’s no way to “tune” an LED panel to the THz range; all light at a given wavelength is already oscillating at that frequency by the laws of physics.
References:
Does Pulsing Lower Effectiveness?
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Pulsing reduces average energy delivered: If you use a 50% duty cycle, you only get half the total dose in the same time. You must double your session length to get the same total energy as continuous mode.
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No magic efficiency boost: There’s no evidence that pulsing delivers “more energy” to cells or makes the same dose more effective (outside of specific neurological protocols).
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Depth of penetration: Some laser research suggests pulsing may increase penetration depth, but this hasn’t been consistently shown with LED panels at therapeutic doses.
Summary: Should You Use Pulsed or Continuous Red Light Therapy?
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Continuous light is well-supported by hundreds of clinical trials for skin, pain, muscle, and general wellness.
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Pulsing may be beneficial in niche cases (neurological applications, specific laser-based protocols), but most “pulsed” LED panels do not deliver on their marketing claims, and there’s no robust evidence of general benefit for skin or muscle use.
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Device accuracy is a serious concern—most consumer products do not output the frequencies or duty cycles they claim.
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Experiment for yourself: Some users anecdotally report different sensations or subjective benefits. If your device offers both, try both and track your results. For most people, either setting will produce similar outcomes for skin, pain, and muscle recovery.
Key Takeaway for Readers
Pulsing in red light therapy is an area of emerging research, but the evidence is still inconclusive—especially for LED panels. If you’re interested in neurological benefits, look specifically for clinical-grade devices targeting 40 Hz. For general wellness, the difference is likely minimal. As always, consult a healthcare provider for advice tailored to your condition.
References & Further Reading:
does quantity of wavelengths matter in a panel?
Red Light Therapy for Skin Care: The Ultimate Guide to Safe and Effective Dosing