The Red Light Therapy Dosage Report

Written By: Jenalee Anderson

Last Updated: May 15, 2025

Are You Overdoing Red Light Therapy? A Study Reveals Optimal Dosage Is Much Smaller Than You Think

According to a landmark study, a majority of red light users may be applying too much light in a single session, leading to diminished results, energy crashes, nervous system dysregulation, and even cellular stress.

In this report, we’ll break down:

What the research says about dosing red light therapy
The overlooked principle of the biphasic dose response
How too much light can actually suppress cellular function
A true story of a client who “overdosed” red light therapy after one session
Clear takeaways on how to find your therapeutic window — and avoid overdosing

Key Highlights + Statistics

20% of adults have tried red light therapy, but many may be overdosing. A study found that 1 in 5 adults have used red light therapy, with usage rising to 46% among those under 35. However, without proper guidance, many users may be applying excessive doses, potentially reducing the therapy's effectiveness.
Most red light guidelines overshoot the optimal dose by 3-12x. For neurological or systemic targets (like the brain or vagus nerve), popular red light panel instructions often recommend over 1000% more energy than the body needs. Even for muscle, skin, and joint use, common advice exceeds the ideal window by 260% or more, according to published research.
High doses (50–100 J/cm²) can be detrimental. Research indicates that while low doses of red or near-infrared light are safe and beneficial, large doses in the range of 50–100 J/cm² may negate positive effects or even cause cellular stress and imbalance.
Sensitive areas require lower doses. For applications involving the brain, nervous system, organs, or endocrine system, optimal doses are typically in the range of 1–3 J/cm². Exceeding this range may lead to diminished benefits or adverse effects.

Red Light's Rise–and Its Misuse

Red light therapy has exploded in popularity — from full-body panels to facial wands to red saunas, it’s everywhere.

And most of the messaging sounds the same:

Screenshot 2025-05-14 at 10.54.05 PM.png

But emerging conversations in both the scientific and clinical communities are challenging that assumption.

What if more isn’t better?

What if — for many users — red light is being overused, misapplied, or even misunderstood?

At Restore, we’ve worked with clients who came to us frustrated and confused. They had done “everything right” — bought a high-end device, followed the brand’s protocol, and committed to regular use.

But instead of feeling calm, energized, or pain-free, they felt… wired. Restless. Uneasy. And in some cases — worse.

The Problem? It Might Be Dosing.

Despite the precision needed to create biological change, most red light guidelines are shockingly imprecise.

The average consumer is told:

Stand 6-12 inches away
Use it for 10–20 minutes
Repeat as needed

No attention is given to:

How much light actually reaches the tissue
Where it’s being applied
How sensitive that person might be to light
What energy system or organ it’s targeting

This lack of nuance is where misuse begins.

What the Research Actually Says

The Biphasic Dose Response Explained

A landmark 2017 review by photomedicine researcher Dr. Michael R. Hamblin analyzed decades of studies in light therapy.

One of its key findings?

Red light therapy follows a biphasic dose response curve.

Biphasic = Two Phases

1. Low Doses

stimulate mitochondria, reduce inflammation, support healing

2. High Doses

reduce or reverse those effects — sometimes even causing harm

This is sometimes called the Arndt-Schulz law, and it’s not unique to red light.

Many therapeutic interventions follow it — including exercise, certain medications, and even essential nutrients like vitamin D.

There is a dose window in which photobiomodulation is effective, and doses above or below this window may have diminished or even adverse effects.

– Hamblin, 2017

Red Light Therapy Dose Curve: Why More Isn't Better

Red light therapy isn't one-size-fits-all.

Systemic applications — like brain, vagus nerve, or hormonal regulation — involve sensitive tissues that require very low doses (1–3 J/cm²) for optimal results.
Superficial applications — such as muscle recovery, joint pain, and skin health — tolerate and often benefit from higher doses (5–15 J/cm²).

Doses that exceed the ideal range in either application can reduce effectiveness — or even backfire — due to the biphasic dose response.

What Is the Optimal Dose?

According to Hamblin’s research:

Optimal Dose Range: 1–3 J/cm² for systemic applications and 5-15 J/cm² for superficial applications.
Diminished Returns: Doses exceeding the optimal range may lead to reduced efficacy.
Potential Negative Effects: Very high doses, particularly in the range of 50–100 J/cm² can not only negate benefits but may inhibit mitochondrial activity.

Let’s put this into context.

Many full-body panels deliver 60+ mW/cm² at 6 inches. If someone stands in front of it for 20 minutes, they might be receiving 72 J/cm² or more — far outside the proven therapeutic window.

This is a massive overshoot for most conditions, tissues, and nervous systems.

The Error in Common Panel Guidelines

And this is per area — meaning someone doing face, thyroid, gut, and legs could be absorbing 40–100 J/cm² in a single session, in other words a 300-900% overdose for superficial tissues and up to 3000% overdose for sensitive tissues.

What Happens When You Overdose?

High doses don’t just waste time — they can cause temporary or long-lasting imbalance in the body.

Some effects clients report:

Insomnia
Nervous system dysregulation (wired/tired feeling)
Headaches or pressure behind the eyes
Irritability or mood instability
Fatigue and burnout
Inflammatory flare ups
Plateaus in therapeutic progress

Real Client Story: "I tried red light once and quit."

I tried a session with a popular panel. It felt relaxing at first, but that night I was wired, couldn’t sleep, and felt off for days. I thought red light wasn’t for me.

We’ve had multiple clients come to Restore after abandoning red light altogether.

What they didn’t realize is that they were likely overdosing — applying a full-panel, full-body dose to already overloaded systems like the adrenals, vagus, and brainstem.

Once we brought their dose down — and redirected light to the right areas — everything changed:

Calm returned
Sleep deepened
Emotional patterns softened
And red light finally worked the way they’d hoped it would

Finding Your Right Dose

It's not about how many times per week alone.

It's about the dose per session x frequency–in other words:

Cumulative dose per week = total energy delivered to tissues over time. Too much in a single session or too little across the week can both lead to ineffectiveness or overstimulation.

Notes for clarity:

Estimated Dose: Based on 660nm LED output at ~60 mW/cm², decreasing with distance due to the inverse square law.
Devices with 810-850nm infrared in addition to 660nm red light, will significantly impact both the depth of penetration and total dose delivered.
Infrared also follows a biphasic dose curve with effective doses for deep tissue around:
- ~10-15 J/cm² for therapeutic stimulation
- >50 J/cm² can trigger cellular inhibition or negative systemic effects
Combined output (RL+IR) = combined dose

! Why face masks require caution:

The brain, pineal gland (melatonin regulation), and cranial nerves are close to the surface.
A “superficial dose” applied systemically can cross the line into overstimulation.
Even though the application feels local (face), you're affecting a highly sensitive, systemic region — more like a precision application.

Calculating Your Dose

The mathematical equation to calculate dose (energy density) in photobiomodulation (red light therapy) is:

Dose (J/cm²) = Power Density (mW/cm²) × Time (seconds) ÷ 1000

Where:

Dose = Energy delivered per unit area, in Joules per square centimeter (J/cm²)
Power Density (also called irradiance) = Light power output per unit area, in milliwatts per square centimeter (mW/cm²)
Time = Exposure time, in seconds
The division by 1000 converts milliwatts to watts (since 1 watt = 1000 milliwatts), matching units so dose ends up in joules.

Example:

If a device emits 60 mW/cm² and you expose the skin for 30 seconds, then:

How to Reset If You've Been Overdoing It

If you suspect your red light routine has been too aggressive, here’s a 3-step nervous system reset:

Pause for a Minimum of 48 Hours (and 2+ weeks depending on severity). Let your system rest. Drink lots of water.
Reintroduce with One Area of Focus. Find a recommended dosage in the chart based on your goals and device, and stay within the limits.
Observe. Track your sleep, energy, and mood. If the response is positive, continue — but slowly.

Key Takeaways

Red light has a sweet spot — too much can reduce effectiveness
Precision application can significantly reduce time while delivering systemic benefits
Nervous system reactions (like insomnia) are often signs of overstimulation
More time ⧣ better results
More power ⧣ advanced healing

Final Thoughts

Red light therapy is profoundly therapeutic when used in the right dose — and just as disruptive when misapplied.

The good news? You don’t need to throw away your device.

You just need to change how you use it.

Approach it like medicine. Like acupuncture. Like tuning a string instrument — not flooding a system with volume.

Your body knows how to respond — it just needs the right signal.

We hope this report empowers you with the information you need to get the best results.

Hamblin's original research can be found here.