Is All Light Equal When it Comes to Red Light Therapy for Fertility?

In the world of photobiomodulation and red light therapy you may have heard the phrase: “A photon is a photon is a photon.” This idea, often associated with Dr. Tiina Karu one of the pioneering scientists in this field. This statement suggests that the body doesn’t care whether light comes from a laser or an LED - as long as it has the right wavelength and energy density, it should have the same effect.

But is this really true?

Science, and real-world clinical applications are not in agreement with that statement. And if you’re using red light therapy for deep tissues, like reproductive health, this distinction matters a lot and as you’ll see here when you understand the history of red light therapy.

The Jackhammer vs. Scalpel Analogy: Why the Tool Matters

Russian laser therapy expert Sergey Moskvin and colleague of Tiina Karu (2017) challenges the ‘light is light’ assumption with a perfect analogy:

“You cannot use a jackhammer instead of a scalpel for a surgical operation, despite both being made of iron.”

In other words, just because both lasers and LEDs emit photons doesn’t mean they function the same way inside the body.

Yes, both light sources can trigger a photobiological response. But critical factors like coherence, collimation and monochromaticity play a massive role in how effectively that light reaches deep tissues, such as the ovaries, uterus, and reproductive organs.

What are the Key Differences?

1. Coherence: Laser vs. LED

A laser emits coherent light—meaning all the photons travel in sync, like soldiers marching in perfect formation. This allows the energy to penetrate deeper into tissues and deliver more focused, therapeutic effects. An LED, on the other hand, emits incoherent light, which means photons scatter in different directions. While this can be fine for surface-level treatments, it results in less penetration into deeper tissues like the ovaries or uterus. So, if you're using PBM for fertility, egg quality, or implantation support, you want that light to reach deep enough, something an LED simply can't do as effectively as a laser. Is that 830 nm red light you purchased really 830 nm or is it spread over 800 nm - 850 nm. Exactly wavelenght matters.

2. Collimation: How Far Does the Light Go?

Lasers emit collimated light, meaning the beam travels in a straight, narrow path without spreading much. This makes it highly targeted and effective for deep tissues. LEDs scatter light in all directions, reducing the amount of energy that actually reaches the target area. Imagine trying to shine a flashlight through your hand, the light disperses and loses power before it can do much. That’s what happens with LEDs when treating deeper tissues.

3. Laser Speckle

Laser speckle is a unique pattern of light interference that happens when coherent laser light interacts with tissues, creating tiny fluctuations in intensity that stimulate deeper biological effects. Think of it like raindrops on a pond, the ripples spread out and interact, creating movement and energy. In tissues, this effect enhances microcirculation and cellular response, making laser therapy more effective for deep regenerative effects. LEDs, on the other hand, emit scattered, incoherent light, which is like throwing a handful of pebbles into a pond, each one makes a tiny splash, but there’s no structured wave effect. This is why lasers can penetrate deeper and activate more powerful biological responses compared to LEDs in photobiomodulation (PBM).

Lasers deliver a much higher concentration of energy in a focused beam.

LEDs spread energy out, making them less efficient for deep tissue treatments.

This is especially critical for fertility treatments, where reaching deep into the pelvic region is necessary.

Why This Matters for Reproductive Health

If you’re investing in PBM for fertility, hormone regulation, or endometrial health, you need a light source that actually reaches the reproductive organs. If you have a reproductive diagnosis such as PCOS or are over 35, don’t waste time with panels or hyped up lights.

➡️ Lasers = Deep penetration, precise targeting, and effective energy delivery.

➡️ LEDs = More superficial effects, energy lost before reaching deeper tissues.

The idea that “all light is the same” misleads women who are looking for real solutions to improve their fertility. It's unfortunate that several influencers and device manufacturers have adopted this out-of-context information. Consider this - if LEDs were as effective as laser there would be no need for the recent increase in ‘high powered’ LED devices that claim to be as effective as laser but also generate significant heat. Red light therapy is NOT a thermal modality - the heat increases circulation to the skin, so more of the photonic energy is absorbed into surface level tissues and the blood - not deep in the reproductive tissues.

Bottom Line: Light Isn’t Just Light - The Right Tool Matters

While all light has biological effects, the source, delivery, and penetration depth determine how effective it is. Saying “light is light” is like saying all exercise is the same, whether you're lifting weights or just waving your arms around.

For serious PBM treatments, especially for deep reproductive health, lasers outperform LEDs. All of the published fertility research used laser treatment - so why are so many health coaches and influencers hiding this from the public? It could be ignorance (there’s a lot to learn) or a marketing ploy.

So if you’re using red light therapy for fertility, make sure you’re using the right tool for the job - not just any glowing red light.

Tracy

*For laser treatments specific to women’s health and fertility in Central Texas - visit the Solasta website and learn more about the power of therapeutic lasers for health.