Photobiomodulation: Does Low-Level Laser Therapy Actually Work for Muscle Building?

2026-02-17

If you have been paying attention to the recovery tech space, you have probably seen the claims: red light therapy beds, laser devices, LED panels — all promising faster recovery, more muscle, and better performance. The technology goes by many names: low-level laser therapy (LLLT), photobiomodulation (PBM), cold laser therapy. But the big question is simple: does it actually work?

The short answer: the evidence is promising for certain applications, but it is not a magic bullet. Let us break down what the research actually says.

What is Photobiomodulation?

Photobiomodulation is exactly what it sounds like — using light to modulate biological processes. The therapy uses red (around 600-700 nm) and near-infrared (around 700-1000 nm) wavelengths of light to penetrate tissue and stimulate cellular processes, particularly in the mitochondria.

The key mechanism involves cytochrome c oxidase, a molecule in mitochondrial electron transport chains that absorbs red and near-infrared light. When this molecule is "excited" by light, it increases ATP production, reduces oxidative stress, and can modulate inflammation — all things that should, in theory, support muscle recovery and growth.

The Research on Exercise Performance and Recovery

A 2024 systematic review in the Journal of Photobiomodulation found that LLLT applied before exercise can reduce muscle fatigue and. The mechanisms appear to involve improve performance reduced oxidative damage and improved calcium handling in muscle fibers.

In practical terms, studies using pre-exercise LLLT have shown:

Reduced muscle damage markers post-exercise (creatine kinase, LDH)
Lower perceived soreness 24-72 hours after training
Improved recovery of force production between sessions
Small but meaningful improvements in time to exhaustion

The typical protocol in research settings involves applying the light to the target muscle group for 60-240 seconds per area, with power densities of 5-100 mW/cm², typically 5-20 minutes before exercise.

What About Muscle Growth?

This is where the evidence gets more nuanced. LLLT appears to be much better at supporting recovery than directly driving hypertrophy. The research consensus suggests:

LLLT alone does not cause muscle growth — you still need the mechanical stimulus of resistance training
LLLT may enhance the recovery environment, allowing for harder or more frequent training
Combination effects appear strongest when LLLT is used consistently over weeks alongside progressive training

One of the more interesting findings: the 2024 meta-analysis found that LLLT seems to work best as a "force multiplier" for training — not as a replacement for good programming, but as something that might help you train harder or recover faster between sessions.

The Device Question: Laser vs. LED

This matters more than most people realize. The research literature predominantly uses actual lasers (Class IIIb), which deliver concentrated light to deeper tissue. LED devices, while cheaper and more accessible, may not penetrate as deeply and their clinical evidence base is weaker.

The FDA classifies LEDs differently from laser diodes, meaning LED devices are not subject to the same federal performance standards. That does not mean LEDs do not work — but it does mean the evidence base for LEDs is less robust.

If you are going to invest in a device, look for:

Wavelengths in the 650-900 nm range — this is the sweet spot for tissue penetration
Power output specifications — research typically uses 5-100 mW/cm²
Actual lasers over LEDs if deep tissue treatment is the goal

Practical Applications

Based on the current evidence, here is how to think about LLLT:

Best uses:

Pre-workout application to reduce fatigue during session
Post-workout to accelerate recovery and reduce soreness
During injury rehabilitation to support tissue repair
For older adults or those recovering from layoffs where recovery is the bottleneck

Not a replacement for:

Adequate protein intake
Sleep and nutrition
Progressive overload in training

The Bottom Line

Photobiomodulation is not a shortcut to gains — nothing is. But the evidence suggests it is a legitimate recovery tool that can support training adaptations, particularly when used consistently over time. The key is realistic expectations: it is a marginal gain optimizer, not a replacement for the fundamentals.

If you are training hard and hitting your recovery limits, LLLT might be worth adding to your protocol. Just do not expect it to do the heavy lifting for you.

Note: If you have any medical conditions, consult a healthcare provider before starting any new therapy — including light-based treatments.