The Simple Red Light Therapy Dosing Guide (No Math Required)

TL;DR: In a hurry? A commonly used starting range for many goals is 10–20 minutes at a distance of 6–12 inches. However, optimal results depend on your specific device. See the table below for commonly referenced ranges.

If you just bought a red light therapy panel and you’re staring at it wondering “how long do I actually stand here?”—I get it. The internet is full of contradictory advice. Manufacturers tell you one thing, Reddit tells you another, and nobody seems to agree.

Here’s what I’ve observed over years of testing consumer-grade panels using a spectrometer. You don’t need a physics degree. You need a simple starting point and the ability to adjust based on how your body responds.

Why Dosing Matters: The Biphasic Dose Response (Simplified)

Red light therapy follows what scientists call a “biphasic dose response.” Think of it like watering a plant.

• Too little water? The plant doesn’t grow.
• Just right? It thrives.
• Too much water? You drown the roots and kill it.

Light works the same way on your cells. There’s a “Goldilocks Zone” where your mitochondria get energized, collagen production ramps up, and inflammation drops. Go below that zone, nothing happens. Go above it, and you actually inhibit the beneficial effects.

This isn’t just my opinion—it has been demonstrated across a large body of published research. The tricky part is that your “zone” depends on three things: your device’s real power output, distance from the panel, and session length.

Most manufacturers lie about power. I’ve measured $800 panels that claim 100mW/cm² but deliver only 60mW/cm² at 6 inches. That’s why following the manual blindly can lead to disappointing results.

Rule-of-Thumb Usage Table

Instead of complex math, here are the ranges used by most experts and practitioners.

Goal	Distance	Time
Skin Health / Anti-Aging	12–18 inches	5–10 mins
Deep Tissue / Muscle Recovery	6–12 inches	10–20 mins

It is well-documented that longer wavelengths (near-infrared) penetrate deeper into tissue compared to visible red light, which is why we stand closer for muscle recovery.

Fred’s Note: These are estimates based on standard panels (100–150W total power, mixed 660nm/850nm). Individual responses vary, and comfort levels can differ between users. If your skin feels uncomfortably warm during a session, move back.

Want Exact Numbers?

For a precise calculation based on your specific device’s power output, use our RLT Calculator here. Plug in your panel’s specs (or measured irradiance), and it’ll give you an exact target time.

Does Power Output Matter? (My Lab Measurements)

Yes. Massively.

Here’s the problem: companies advertise “total solar power” (like 300W) because it sounds impressive. What actually matters is irradiance—the power density hitting your skin, measured in milliwatts per square centimeter (mW/cm²).

I use a professional spectrometer to test panels. Last month I measured a popular panel that advertised “5-minute sessions.” Real irradiance at the recommended distance? 42mW/cm² instead of the claimed 100mW/cm². If you followed their timer, you’d get less than half the intended dose.

This is why I always say: if the box says 5 minutes, you might actually need 7-8 minutes because real power is often 30-40% lower than claimed.

The Importance of Distance (Inverse Square Law)

Moving your body just a few inches can drastically change the dose. This is due to the Inverse Square Law. In simple terms: moving just a few inches closer or farther can dramatically change the dose.

If you are treating deep tissue issues, stay within the 6-12 inch range to ensure enough photons reach the target.

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