Timing your red light therapy sessions relative to exercise is one of the most frequently asked questions — and one with a surprisingly clear answer from the research. Whether to use it before or after a workout depends on your primary goal: performance enhancement or faster recovery.

Using Red Light Therapy Before Exercise

Pre-workout red light therapy (RLT) is sometimes called "pre-conditioning" or "photobiomodulation pre-treatment." Studies show it can:

  • Increase muscle output and endurance — A 2016 study in Lasers in Medical Science found athletes who received RLT before leg exercises had significantly greater torque and lower fatigue than controls
  • Enhance mitochondrial function ahead of demand — Boosting ATP production before you deplete it through exercise
  • Reduce pre-exercise inflammation — Lowering baseline inflammation before strenuous activity
  • Improve VO₂ max over time — Regular pre-workout use has been linked to improved aerobic capacity in several trials

When to do it: 10–30 minutes before training. Allow enough gap that the circulation-boosting effects are active during your session.

The Research Verdict on Pre-Workout RLT

A 2021 meta-analysis of 46 randomized controlled trials found pre-exercise photobiomodulation consistently improved muscle performance by 8–12% on average. The effect was strongest for lower-body compound movements.

Using Red Light Therapy After Exercise

Post-workout RLT is the more popular approach and has the largest volume of research behind it. It works by:

  • Reducing delayed onset muscle soreness (DOMS) — Multiple trials show significant reductions in soreness 24–72 hours after exercise when RLT is applied immediately post-workout
  • Accelerating creatine kinase clearance — CK is a marker of muscle damage; faster clearance means faster recovery
  • Reducing inflammatory cytokines — IL-6, TNF-α, and other pro-inflammatory markers are suppressed by RLT
  • Supporting muscle protein synthesis — Light-stimulated ATP supports the energy-intensive process of building new muscle tissue

When to do it: Within 2 hours post-workout delivers the strongest acute recovery effects. Many elite athletes use it within 30 minutes of finishing training.

Can You Do Both?

Yes — and some protocols use RLT both before and after. Professional sports teams (including several NBA and NFL teams) reportedly use pre-game RLT for performance and post-game for recovery. If time is limited, prioritize post-workout for most goals, or pre-workout if your primary aim is performance enhancement during the session.

Practical Timing Guide

  • Goal: Strength & performance → Pre-workout (15–30 min before)
  • Goal: Recovery & DOMS reduction → Post-workout (within 30–60 min)
  • Goal: Muscle growth (hypertrophy) → Post-workout (supports protein synthesis)
  • Goal: Endurance → Pre-workout or both