Optimizing Workout Recovery & Performance with Red Light Therapy

We aren’t making any claims in this article, we are simply sharing research. 

This article examines the optimal timing of red light therapy around exercise, analyzing the current science on pre- vs post-workout application.

Red light therapy has surged into the fitness world like a quiet little superpower, lighting up warm-ups and cool-downs everywhere. Athletes and everyday movers alike report remarkable shifts in how they perform and recover, which naturally sparks two big questions: Which type of light therapy device delivers the best boost? and Is it more effective before a workout, after, or both?

To settle the dust, the research was gathered, sifted, and studied. The body of evidence already paints an intriguing picture, and the emerging science surrounding red light therapy’s impact on workout performance is far more encouraging than many expect.

Red Light Therapy and Workout Timing: A Quick Performance Overview

• The research to date points in a remarkably unified direction. Every study so far reports some form of benefit, whether in recovery, peak performance, lactate response, or discomfort reduction, and none have identified adverse effects.
• It’s worth noting that most of this work has focused on 808 and 810 nm wavelengths rather than 850 nm. So any brand insisting that 850 nm is the onlywavelength that matters for performance is stretching the truth. That said, there are studies showing promising outcomes with wavelengths in the high-800s and low-900s as well.
• Systematic reviews echo the same theme: near-infrared wavelengths have been more thoroughly studied and often shine brightest for deep muscle support due to their greater penetration. Still, there’s no need to choose sides. A blend of red and near-infrared light tends to offer the most complete toolkit, since red light carries its own mitochondrial and cellular advantages that complement deeper-reaching wavelengths.
• Across the research landscape, the reported benefits stack up impressively: reduced soreness, improved mitochondrial efficiency, increases in muscle mass, strength, and endurance, quicker recovery, decreased discomfort, and more.
• Systematic reviews suggest that timing matters. The sweet spot appears to be using red light therapy three to six hours beforetraining, rather than immediately beforehand. Pre-workout use also has a slight advantage over post-workout use, largely because it’s been studied more extensively.
• For dosing, up to 60 Joulestends to deliver the strongest results. Once studies drift into the low hundreds, the benefits often reverse, so it’s wise not to overdo it.
• Most high-powered panels on the market can serve well for performance support. For an extra edge, look for devices that deliver plenty of 810 nm output, since this wavelength shows up repeatedly in the research. Higher-powered panels also have the advantage of deeper penetration, which may enhance their impact.

Introduction: The Ongoing Quest to Unlock Better Workout Performance

Humanity’s pursuit of a performance edge stretches back to the earliest stories we bothered to carve into tablets (1; 2). Milo of Croton famously hoisted a calf that grew heavier by the day, building his strength alongside it. Centuries later, Aristotle had his budding thinkers grapple as part of their intellectual training, weaving physical challenge into mental discipline.

Fast-forward to today and the menu of “enhancement” tactics has exploded. People reach for ashwagandha, zinc, cold plunges, creatine, and a whole parade of supplements and recovery rituals (3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14). Some hold up under scrutiny, others unravel, and time tends to separate the genuine helpers from the glittery impostors. Recent research, for example, suggests that cold baths may blunt adaptations or perform no better than simple active recovery, despite the widespread belief that they’re a post-workout magic wand.

To understand whether red light therapy works best before or after training, the clearest path is through the research already on the table. Fortunately, there’s a solid body of evidence examining its impact on performance.

It’s worth noting that these studies don’t focus solely on classic gym sessions. Researchers have explored red light therapy across a wide range of sports and physical activities. Including that broader spectrum makes the picture more complete, and it reflects reality: while some of us adore the weight room, most people move their bodies in countless other ways. This blog embraces all of those findings.

In the next section, we’ll break down the studies examining red light therapy used before or after workouts. From there, conclusions will be drawn based on the overall trends in the research. The aim is to present each study clearly and fairly. Both animal and human research are included, and when their outcomes differ, that distinction will be noted in the analysis.

With that foundation in place, let’s explore what the research reveals about red light therapy, recovery, and workout performance.

Examining Red Light Therapy and Workout Performance

This section outlines the studies that have examined red light therapy used before or after workouts. For those who want to explore the details, the next pages highlight fifteen studies selected to illustrate the range of evidence currently available. Their collective patterns offer insight into how red light therapy may influence performance and recovery. A later section also incorporates findings from systematic reviews to provide a more comprehensive perspective.

Study 1: Effects of Red Light Therapy applied before or after plyometric exercise on muscle damage markers

The opening study explores how red light therapy influences outcomes when used before or after plyometric exercise (15).

Its key finding is clear: participants experienced reduced muscle soreness and improved muscle quality.

The design of the study is notably easy. Light therapy was applied at two different time points—either prior to the plyometric session or immediately afterward. Plyometrics, also known as jump training, involves exercises in which muscles exert maximum force in short intervals of time, with the goal of increasing power, speed and strength (16; 17).

The researchers evaluated three primary outcomes:

1. muscle tissue echo measurements, which indicate tissue quality;
2. muscle soreness, assessed using the Visual Analogue Scale (VAS), a 1–10 subjective pain rating;
3. maximal voluntary contraction of the quadriceps muscles.

Two of these areas showed improvement. Tissue quality and soreness both responded positively to red light therapy, while strength measurements did not change within the three-day post-exercise window used in the study.

Taken together, these findings offer an early signal that red light therapy may support recovery when used around workouts. The specific protocol used in this trial is outlined below, as it becomes relevant to the broader conclusions drawn later in the analysis.

"Placebo and LLLT (810 nm, 200 mW per diode, 6 J per diode, 240 J per leg) were randomly applied on right/left knee extensor muscles of each volunteer before/after a plyometric exercise protocol." (15).

Study 2: Elderly Rats Show Improved Inflammatory Biomarkers After Aerobic Exercise with Red Light Therapy

The next piece of evidence comes from an animal study (18). It involved 24 aged rats alongside a group of six younger rats for comparison. The study design was structured as follows:

"The older animals were randomly divided into four groups designated as follows: aged-control, aged-exercise, aged-LLLT, aged-LLLT/exercise group, and young-control animals. Aerobic capacity (VO2max) was analyzed before and after training period. The aged-exercise and aged-LLLT/exercise groups were trained for 6 weeks. LLLT laser was applied before each training session with 808 nm and 4 J of energy to the indicated groups throughout training. The rats were euthanized, and muscle tissue and serum were collected for muscle cross-sectional area and IL-6 and TNF-α protein analysis." (18)

Some groups performed aerobic exercise while others remained sedentary, and red light therapy (LLLT) was administered to only a portion of the rats. The wavelength used was 808 nm, aligning closely with the 810 nm applied in several human studies. At the conclusion of the experiment, tissue samples were collected for analysis. The resulting findings are summarized below:

"Levels of IL-6 and TNF-α for the aged-exercise and the aged-LLLT/exercise groups were significantly decreased compared to the aged-control group (p < 0.05). Analysis of the transverse section of the gastrocnemius muscle showed a significant difference between the aged-exercise and aged-LLLT/exercise groups (p < 0.001). These results suggest that laser therapy in conjunction with aerobic training may provide a therapeutic approach for reducing the inflammatory markers (IL-6 and TNF-α), however, LLLT without exercise was not able to improve physical performance of aged rats." (18)

Overall, the treatment improved inflammatory biomarkers, though it did not enhance physical performance in the older rats. Now, turning back to human research:

Study 3: Human Biceps Performance Shows Reduced Lactate, Lower Inflammation, and Enhanced Endurance

The next piece of research involves human participants once again (19). The study design was straightforward and well-structured:

"Nine healthy male volleyball players participated in the study. They received either active LLLT (cluster probe with 5 laser diodes; lambda = 810 nm; 200 mW power output; 30 seconds of irradiation, applied in 2 locations over the biceps of the nondominant arm; 60 J of total energy) or placebo LLLT using an identical cluster probe. The intervention or placebo were applied 3 minutes before the performance of exercise. All subjects performed voluntary elbow flexion repetitions with a workload of 75% of their maximal voluntary contraction force until exhaustion." (19)

Once again, the study employed the 810 nm wavelength. Notably, the reported power output reached approximately 200 mW/cm², which is considerably higher than the commonly cited upper limit of 100 mW/cm² often referenced in commercial discussions. To clarify this point, the full study text provides the following explanation:

"Power density 5.495 W/cm2 (for each laser spot) [5 lasers are used in total]

Energy density: 164.85 J/cm2 (for each laser spot)" (20)

Compared with the output of typical red light therapy panels, the dosage delivered in specific areas of this study was exceptionally high.

The key takeaway is striking: biceps endurance improved, and markers of inflammation and lactate in the blood decreased with red light therapy. These findings point toward meaningful performance and recovery benefits.

Despite the intense localized application, the total dose was only 6 Joules, which is relatively low. What stands out most is that a very high concentration of light applied to precise points produced broader positive effects across the entire muscle, as long as the overall dosage remained within an optimal range.

Study 4: Human Quadriceps Show Enhanced Performance Following LLLT

This study used red light therapy in the 800 nm range once again, this time at 830 nm (22). Conducted in 2014, it comes from a highly productive Brazilian research group responsible for much of the foundational LLLT literature. The trial involved 27 soccer players who were split into three groups. Lasers, rather than LEDs, were used, though broader evidence suggests that LEDs can perform comparably to lasers in many general applications (23).

The study was structured as follows:

"The experiment was performed in two sessions, with a 1 week interval between them. Subjects performed two sessions of stretching followed by blood collection (measurement of lactate and CK) at baseline and after fatigue of the quadriceps by leg extension. LLLT was applied to the femoral quadriceps muscle using an infrared laser device (830 nm), 0.0028 cm(2) beam area, six 60 mW diodes, energy of 0.6 J per diode (total energy to each limb 25.2 J (50.4 J total), energy density 214.28 J/cm(2), 21.42 W/cm(2) power density, 70 sec per leg. We measured the time to fatigue and number and maximum load (RM) of repetitions tolerated. Number of repetitions and time until fatigue were primary outcomes, secondary outcomes included serum lactate levels (measured before and 5, 10, and 15 min after exercise), and CK levels (measured before and 5 min after exercise)" (22).

In essence, the intervention groups received 830 nm light applied directly to the quadriceps. All participants then completed performance testing that measured time to exhaustion and peak output. Blood samples were also analyzed for lactate and creatine kinase (CK), a key marker of inflammation.

The results were strongly in favor of red light therapy’s role in supporting recovery and performance. According to the study’s conclusion, the post-workout treatment group showed a slight advantage in outcomes.

Study 5: Grip Strength and Physiological Measures in Rats

Another study conducted in rats offers additional insight (23). Animal research continues to provide opportunities to examine physiological changes in controlled settings that would be difficult to study in humans. The structure of this experiment is outlined below:

"A total of 64 male Wistar rats were divided into eight groups: control, control LLLT, control exercise, control LLLT and exercise, arthritis, arthritis LLLT, arthritis exercise, and arthritis LLLT and exercise groups. The experimental RA was induced by a complete Freund's adjuvant injection into the knee joint cavity. Climbing exercises and LLLT (660 nm; 5 J/cm2 per point) were performed as the treatment. In addition, muscle strength was evaluated using the grip strength test, and morphometric evaluations were performed on the ankle joint." (23).

“RA” refers to Rheumatoid Arthritis, an autoimmune inflammatory condition that affects the joints (24; 25; 26). It leads to pain, swelling, structural changes, and a decline in the surrounding muscles’ ability to function.

In this study, red light therapy helped restore muscle strength and improved several of the negative morphological features associated with RA. Both exercise and red light therapy provided benefits, creating an interesting pattern in the results.

These findings suggest that red light therapy may hold meaningful value for supporting muscle function in the context of inflammatory joint disease. Yet an important question remains:

Why does this matter for individuals without RA or for those considered generally healthy? Because numerous other studies demonstrate similar benefits in healthy young animals and humans as well:

Study 6: Red Light Therapy Boosts VO₂ Max in Rats

Another study from the Brazilian research group mentioned earlier focuses on rats once again (27). This time, the primary outcome was inflammation, a factor that directly influences VO₂ max — a valuable indicator of the body’s ability to deliver and utilize oxygen (28; 29; 30). The study’s well-crafted abstract summarizes the findings as follows:

"Thirty Wistar rats (Norvegicus albinus) (24 aged and six young) were tested. The older animals were randomly divided into aged-control, aged-exercise, aged-LLLT, aged-LLLT/exercise, and young-control. Aerobic capacity (VO2max(0.75)) was analyzed before and after the training period. The exercise groups were trained for 6 weeks, and the LLLT was applied at 808 nm and 4 J energy. The rats were euthanized, and muscle tissue was collected to analyze the index of lipid peroxidation thiobarbituric acid reactive substances (TBARS), glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) activities. VO2 (0.75) max values in the aged-LLLT/exercise group were significantly higher from those in the baseline older group (p <0.01) and the LLLT and exercise group (p <0.05). The results indicate that the activities of CAT, SOD, and GPx were higher and statistically significant (p <0.05) in the LLLT/exercise group than those in the LLLT and exercise groups. Young animals presented lesser and statistically significant activities of antioxidant enzymes compared to the aged group. The LLLT/exercise group and the LLLT and exercise group could also mitigate the concentration of TBARS (p > 0.05). Laser therapy in conjunction with aerobic training may reduce oxidative stress, as well as increase VO2 (0.75)max, indicating that an aerobic exercise such as swimming increases speed and improves performance in aged animals treated with LLLT."

Overall, the greatest improvements came from combining red light therapy with exercise rather than using either approach alone. And once again, the study relied on the now frequently appearing 810 nm wavelength, rather than the 850 nm output common in many consumer red light panels.

Study 7: Muscle Thickness and Strength Gains in Male Participants

This next study brings us back to human participants, focusing specifically on male subjects (31). The researchers divided them into three groups:

1. a control group with no exercise or red light therapy;
2. an exercise-only group;
3. an exercise-plus–red light therapy group.

Red light therapy was applied to the quadriceps, the knee extensor muscles at the front of the thigh, and the treatment group received it before every training session throughout an 8-week program.

The results were notably encouraging:

"[The Control Group] presented no changes in any variable throughout the study, while eccentric training led to significant increases in muscle thickness and peak torque in [Training Group] and [Training and Light Therapy Group]. Subjects from [Training And Light Therapy Group] reached significantly higher percent changes compared to subjects from [Training Group] for sum of muscles' thicknesses (15.4 vs. 9.4%), isometric peak torque (20.5 vs. 13.7%), and eccentric peak torque (32.2 vs. 20.0%).”

Here’s why these findings stand out: muscle thickness increased by more than 50 percent in the red light therapy group, and peak torque rose by roughly 60 percent. In simple terms, torque reflects the muscle’s ability to generate force, meaning the participants who received red light therapy became significantly stronger (32).

Study 8: Comparing LEDs and Lasers Used Before Exercise in Human Participants

Another study involving human participants adds to the picture (33). This trial used both LEDs and lasers, applying wavelengths of 670 nm, 875 nm, and 905 nm to the quadriceps. Participants then performed a Maximum Voluntary Contraction (MVC), essentially pushing their upper-leg muscles to full effort. Afterward, researchers measured delayed-onset muscle soreness (DOMS), inflammatory markers, and compared outcomes across different Joule-based dosing levels.

The study reported the following results:

"Phototherapy increased (p < 0.05) MVC was compared to placebo from immediately after to 96 h after exercise with 10 or 30 J doses (better results with 30 J dose). DOMS was significantly decreased compared to placebo (p < 0.05) with 30 J dose from 24 to 96 h after exercise, and with 50 J dose from immediately after to 96 h after exercise. CK activity was significantly decreased (p < 0.05) compared to placebo with all phototherapy doses from 1 to 96 h after exercise (except for 50 J dose at 96 h). Pre-exercise phototherapy with combination of low-level laser and LEDs, mainly with 30 J dose, significantly increases performance, decreases DOMS, and improves biochemical marker related to skeletal muscle damage." (33)

In simple terms, red light therapy was effective at 670 nm and in the high-800 to low-900 nm range, supporting better exercise performance, reduced soreness, and lower inflammatory markers. Another strong point in favor of red light therapy’s role in training and recovery.

Study 9: Effects on fatigue and muscle damage using red light therapy before training in Judo Athletes

Another relevant human study adds valuable insight (34). Sixteen judo athletes participated, with each athlete receiving red light therapy on one randomly selected limb while the other limb served as the control. To induce muscle fatigue and micro-damage, the athletes completed a stretch–shortening exercise session. Jump performance, quadriceps ultrasound measurements, and muscle soreness were then assessed before, during, and after the workout.

The researchers reported the following conclusions:

"No differences were observed between photobiomodulation therapy and placebo at any time points for any variables (p > 0.05), indicating no positive effect favoring photobiomodulation therapy. In conclusion, our findings suggest no effect of photobiomodulation therapy applied before exercise to reduce lower limb muscle fatigue and damage during and following a stretch-shortening cycle protocol in judo athletes." (34).

This was the first study in the collection that did not show a positive result.

According to the full paper, both lasers and LEDs were applied in the 670, 850-880, & 950nm ranges (35). The researchers offered several possible explanations for the lack of measurable benefits, including factors related to participant characteristics and the dosing protocol. Their reasoning isn’t entirely definitive, and outcomes remain somewhat ambiguous. Even within the paper, the authors note that the absence of improvement is not fully understood.

Study 10: Dose-Based Effects of Red Light Therapy on Treadmill Running Performance and Recovery

This next study stands out because it used an LED panel emitting 660 nm and 850 nm light (36). Human participants completed a maximal treadmill test, and prior to that test received either a placebo treatment or doses of 30 J, 120 J, or 180 J per area. The treatment sites included the hamstrings, quadriceps, and the gastrocnemius, the largest calf muscle.

The near-infrared portion of the light output carried slightly higher power, as noted by the researchers:

"The LED was applied using an equipment with 56 diodes of red light (660 nm; 50 mW/cm2 and 1.5 J/cm2 each diode) and 48 diodes of infrared light (850 nm; 150 mW/cm2 and 4.5 J/cm2 each diode)." (36)

In the end, this study found no measurable benefits. Maximum running speed, lactate levels, exercise heart rate, and perceived exertion all remained similar across every group, regardless of dose.

Another example, then, of a trial where red light therapy did not produce a detectable effect.

Study 11: 660 nm Light Enhances Wrist Training Outcomes in Human Participants

A 2020 study adds another layer of insight, using a light setup of 660 nm paired with 830 nm (37). The researchers also incorporated blood-flow-restriction training, a method gaining renewed attention in performance circles.

The participants were divided into four groups:

Group 1: Standard strength training
Group 2: Blood-flow-restriction training
Group 3: Blood-flow-restriction training plus 660 nm light at an 18.9 J dose
Group 4: Blood-flow-restriction training plus 830 nm light at a 17.2 J dose

The 660 nm group demonstrated the strongest overall results, outperforming the 830 nm group in both grip strength and wrist extensor strength. The wrist extensors counterbalance the flexors, which are responsible for gripping actions. Electromyographic measurements were also taken, and once again the 660 nm group showed superior responsiveness compared to 830 nm, indicating more effective neuromuscular activation.

These findings offer another point of support for red light therapy, particularly at 660 nm, as a tool for enhancing performance. Access to the full text was limited, so details regarding application parameters and study duration were not available.

Study 12: Effects of Photobiomodulation Therapy on High-Level Soccer Players before Intense Progressive Running Test 

Another running-focused study examined high-level soccer players (38), this time using 810 nm light. Participants received either red light therapy or a placebo treatment designed to appear authentic before completing a treadmill run to exhaustion. In the study abstract, the researchers outline an extensive list of biomarkers assessed throughout the test:

"We analyzed rates of oxygen uptake (VO2 max), time until exhaustion, and aerobic and anaerobic threshold during the intense progressive running test. Creatine kinase (CK) and lactate dehydrogenase (LDH) activities, levels of interleukin-1β (IL-1-β), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α), levels of thiobarbituric acid (TBARS) and carbonylated proteins, and catalase (CAT) and superoxide dismutase (SOD) activities were measured before and five minutes after the end of the test. PBMT increased the VO2 max (both relative and absolute values-p < 0.0467 and p < 0.0013, respectively), time until exhaustion (p < 0.0043), time (p < 0.0007) and volume (p < 0.0355) in which anaerobic threshold happened, and volume in which aerobic threshold happened (p < 0.0068). Moreover, PBMT decreased CK (p < 0.0001) and LDH (p < 0.0001) activities. Regarding the cytokines, PBMT decreased only IL-6 (p < 0.0001). Finally, PBMT decreased TBARS (p < 0.0001) and carbonylated protein levels (p < 0.01) and increased SOD (p < 0.0001)and CAT (p < 0.0001) activities." (38).

In everyday language, this study shows that red light therapy can influence workout performance across multiple physiological layers. VO₂ max increases, meaning the body becomes more efficient at transporting and using oxygen. Time to exhaustion improves, and athletes are able to sustain anaerobic effort for longer. Several markers related to metabolic stress and byproducts of exertion also shift in a favorable direction.

Overall, the study concludes that red light therapy not only enhances performance but also reduces metabolic strain and oxidative stress after intense exercise, supporting better recovery.

Study 13: Effects of Post-Workout Red Light Therapy on Performance and Inflammation in Water Polo Players

A 2016 human study examined how red light therapy influences performance and inflammation in water polo players (39). Some athletes received a sham treatment, while others received actual red light therapy using 810 nm wavelengths. The therapy was administered for five consecutive days, immediately after each training session, targeting the adductor muscles along the inner thigh.

Before training, participants completed a 200-meter swim sprint and a 30-second crossbar jump test. Blood samples were also collected to evaluate biomarkers. The study reported the following outcomes:

"There was no significant change in the P200 exercise in the LLLT group compared with the placebo group but there was a moderate improvement in the 30CJ (8.7 ± 2.6 %). IL-1β and tumor necrosis factor-alpha presented increased (P < 0.016) concentration within group 48 h after the last LLLT intervention compared to pre, 0, and 24 h, but did not differ between groups. IL-10 increased over time in the placebo group and reached a moderate effect compared to the LLLT group. The creatine kinase decreased significantly (P = 0.049) over the time within the LLLT treatment group, but there was no significant change in lactate dehydrogenase (P = 0.150). In conclusion, LLLT resulted in a non-significant, but small to moderate effect on inflammatory and muscle damage markers and a moderate effect on performance in water polo players" (39).

The findings showed a measurable improvement in performance, though not in the 200-meter swim sprint. In terms of muscle damage, the 810 nm red light therapy group outperformed the placebo group, offering yet another modest advantage for red light therapy.

It’s also notable that the treatment in this study was applied after training, a detail that becomes useful when considering the broader patterns across all 15 studies.

Study 14: Comparing Anti-Inflammatory Painkillers and Red Light Therapy for Muscle Damage in Rats

A 2016 study examined rats with experimentally induced muscle damage (40; 41). The purpose was to determine whether red light therapy could serve as a useful alternative to a class of anti-inflammatory pain medications known as NSAIDs, which research suggests offer limited benefit for muscle injuries and can carry unwanted side effects.

To conduct the experiment, researchers created an injury in the tibialis anterior, the muscle along the front of the shin. They then applied the following detailed treatment protocol:

"After 1 h, rats were treated with PBMT (830 nm, continuous mode, 100 mW of power, 35.71 W/cm2; 1, 3, and 9 J; 10, 30, and 90 s) or diclofenac sodium (1 g). Our results demonstrated that PBMT, 1 J (35.7 J/cm2), 3 J (107.1 J/cm2), and 9 J (321.4 J/cm2) reduced the expression of tumor necrosis factor alpha (TNF-α) and cyclooxygenase-2 (COX-2) genes at all assessed times as compared to the injury and diclofenac groups (p < 0.05). The diclofenac group showed reduced levels of COX-2 only in relation to the injury group (p < 0.05). COX-2 protein expression remained unchanged with all therapies except with PBMT at a 3-J dose at 12 h (p < 0.05 compared to the injury group). In addition, PBMT (1, 3, and 9 J) effectively reduced levels of cytokines TNF-α, interleukin (IL)-1β, and IL-6 at all assessed times as compared to the injury and diclofenac groups (p < 0.05). " (40).

Several power settings of 830 nm light were tested in this experiment. The anti-inflammatory effects produced by red light therapy were comparable to those achieved with topically applied NSAIDs. Among the groups, the 3 J dose delivered the most favorable overall results.

A companion publication based on the same study reported cellular-level findings. Rats were evaluated at 6, 12, and 24 hours after injury, and the researchers observed the following:

"[T]he 9 J (321.4 J/cm2) dose was the most effective in organizing muscle fibers and cell nuclei. On the other hand, the use of diclofenac sodium produced only a slight improvement in morphological changes. Moreover, we observed a statistically significant increase of muscle work in the PBMT 3 J (107.1 J/cm2) group in relation to the injury group and the diclofenac group (p < 0.05). The results of the present study indicate that PBMT, with a dose of 3 J (107.1 J/cm2), is more effective than the other doses of PBMT tested and NSAIDs for topical use as a means to improve morphological and functional alterations due to muscle injury from contusion." (41).

Once again, the 3 J dose produced the strongest results. Overall, the study suggests that red light therapy can match the effects of NSAIDs in supporting recovery from muscle injury and even surpass them in certain areas, particularly given the lack of side effects.

Now, on to the final study:

Study 15: Laser Therapy and Its Influence on Muscle Performance During Exercise

To add another layer to the discussion, this study examined the use of red light therapy during exercise (42). Young male participants received either an 808 nm laser treatment or a sham intervention, and a crossover design ensured that each participant experienced both conditions. The training protocol was structured as follows:

"The training sessions consisted of three sets of 20 RM of knee flexion-extensions using an isokinetic dynamometer at 60 degrees/sec plus LLLT (808 nm, 100 mW, 4 J), or placebo, applied to quadriceps femoris muscles between sets, and after the last series of this exercise. After 1 week (washout period), all volunteers were exchanged among groups and then all assessments were repeated." (42).

Between the 20-repetition maximum (RM) sets and again after the final set, participants in the intervention group received a 4 J dose of 808 nm light.

The results showed that red light therapy enhanced repetition performance and improved scores on the electromyography fatigue index, indicating better muscle endurance. This suggests that red light therapy can be beneficial not only before or after exercise, but even during a training session.

However, findings like these add complexity to the original question of optimal timing. To gain a clearer perspective on the broader landscape, several systematic reviews were consulted to compare their conclusions, which draw from larger datasets than the individual studies summarized here.

Findings from Systematic Reviews on Red Light Therapy Used Before or After Workouts

This section summarizes several systematic reviews evaluating red light therapy for sports performance (43), addressing each one individually.

The first review, published in 2021 and therefore highly current (43), echoes the findings seen across many of the individual studies discussed earlier. It concludes that red light therapy can enhance both training outcomes and competitive performance. At the same time, the authors note that important questions remain regarding optimal use, including timing, dosage, and application strategies:

"The biggest questions about PBM applied in sports are still open, as follows [..]: Optimal wavelengths, optimal time, before or after, or both, and at what interval of physical activity? Optimal PBM parameters (power density, fluency, modulation frequency)? The number of points for each muscle? The interaction of PBM with muscles and the chain of biochemical reactions triggered inside cells and ultimately reflected in increased performance in sports? Considering the notorious biphasic dose response, typical of PBM and its interaction with muscles, i.e., could it be managed, controlled or achieved without great difficulty to apply exactly as much energy as we need and not too much irradiation? Is it right to combine different light sources, i.e., both lasers and LEDs?" (43)

These are the practical questions that routinely surface in real-world use. Many of these uncertainties are highlighted in educational content from experienced practitioners, where topics such as ideal wavelengths, optimal Joule dosing, recommended frequency of use, and the comparison between lasers and LEDs are all discussed as still-evolving areas.

The systematic review reflects the same reality: meaningful benefits are evident, but the finer details of best practices remain open for further clarification.

The takeaway is straightforward: red light therapy is effective, but no single, universally applicable protocol exists. Athletes vary widely in genetics, mitochondrial function, training styles, and lifestyle factors; are these factors something we need to take into account? Does that make the idea of one “perfect” protocol unrealistic? The jury’s out.

Future research will need to adopt more consistent parameters or establish standardized treatment frameworks. As it stands, the current studies differ greatly in their methods, including wavelengths, treatment times, device types, and dosing approaches.

Even so, the systematic review notes that doses up to 60 J appear most effective (43), with around 10 J serving as a reasonable minimum when used before a workout. Research now includes a substantial number of LED-based studies, not just laser-focused ones, and LEDs consistently demonstrate strong results. High-powered lasers, by contrast, may pose greater risks, particularly for elite athletes. Exploration into full-body red light therapy beds is also in its early stages.

All of this underscores just how layered and complex the topic truly is. Multiple physiological systems appear to be influenced, including:

1. Improved mitochondrial function
2. Enhanced circulation
3. Faster recovery from injuries
4. Increases in bone density
5. Greater ease in building muscle and reducing body fat
6. Reduced muscle soreness
7. Support for managing persistent pain
8. Accelerated tissue repair
9. Improved general well-being
10. Better sleep quality
11. Increased collagen production
12. Sharper cognitive performance

Now consider the fact that all of these variables interact, influencing one another while also shaping overall sports and workout performance.

With that in mind, two additional red light therapy reviews offer further perspective (44; 45).

The first review examined 46 independent studies focused specifically on human muscle tissue and red light therapy (44).

One notable detail is that nearly all of the included studies used contact-based red light therapy, where LEDs or lasers are placed directly against the skin. The contact-versus-distance question has been discussed widely: when devices are positioned several inches away, higher power output is required because some of the light is reflected rather than absorbed. Direct contact minimizes reflection and ensures more efficient delivery.

After reviewing 46 studies in depth, this systematic analysis aligns with the earlier review and highlights the following key point:

"What is (are) the best wavelength(s) to use? When is the best time to apply PBM on muscles? Before or after exercise? If before or after exercise, how long should the time interval between light and exercise be? What are the best PBM parameters (irradiance, fluence, pulse structure)? How many points or sites of irradiation should be used on each muscle group? How exactly does PBM interact with muscle tissue on a biochemical level to increase sports performance? Does the well-known biphasic dose response that is typical of PBM apply to muscles? In other words, is it possible to use too much light?" (44)

In many ways, this brings the discussion full circle.

The review also concludes that, based on current evidence, the most effective wavelength ranges for muscle performance fall between 630–660 nm and 808–950 nm. Near-infrared tends to deliver stronger results overall because it penetrates more deeply into muscle tissue.

Even so, the authors emphasize that using both red and near-infrared together is ideal. A larger share of near-infrared appears especially beneficial, but combining the two regions of the spectrum likely offers complementary advantages at the mitochondrial level.

This is why the LZR Ultrabright LED would be a good fit as it uses both Red and IR at the wavelengths of 660nm and 810nm which is shown to be the most effective according to the research we’ve examined.

Something particularly interesting to point out is the indication that the most effective window for using red light therapy before exercise is 3–6 hours in advance, not just a few minutes prior. Although research on timing is still limited, at least two studies support this approach (46; 47). This timing appears to reduce muscle damage and enhance performance.

Then there’s the option to utilize red light therapy after a workout. The researchers note the following:

"The second strategy is to apply PBM using LLLT or LEDT immediately after each bout of exercise in order to accelerate muscle recovery [...]. This strategy appears to be especially effective when used in combination with regular exercise training programs that can last for days or even weeks [...]. In addition, the use of PBM after each session training of exercise training programs also seems to increase the potential gains of performance, including defense against oxidative stress, muscle cell proliferation, energy muscle content (glycogen and ATP) and mitochondrial metabolism [...], in addition to several other effects reported previously (see review [...). However, this issue is not completely clear in the literature, since a recent study reported better results in favor of muscular pre-conditioning in training programs [...]. We believe that further investigations to answer this question are necessary."

Current evidence suggests there may be a slight advantage to using red light therapy before a workout rather than after. Still, the wide variation in treatment protocols makes firm conclusions difficult. Even so, the overall pattern remains consistent: red light therapy is effective, with far more studies showing benefits than showing no effect.

The next systematic review (45) offers similar insights. It gives a modest preference to near-infrared over red light, largely because near-infrared has been examined more extensively. Yet again, the researchers highlight the lack of agreement on optimal dosing parameters.

The review identifies several key mechanisms influenced by red light therapy, including mitochondrial function, oxidative stress, muscle repair following injury, gene expression, motor unit recruitment, and various metabolic processes. Each of these areas is examined in substantial depth, highlighting the complexity of the underlying biology.

Overall, the findings are positive, yet they stop short of offering precise recommendations for session parameters, again emphasizing how intricate and multifaceted the subject remains.

With these three systematic reviews in mind, the next section examines how these collective insights can be interpreted:

Assessment of Findings from Red Light Therapy Studies and Systematic Reviews

The findings from the individual studies and the systematic reviews align reasonably well, allowing several practical conclusions to emerge:

• Red light therapy is effective when used either before or after a workout. Current evidence suggests a modest advantage for pre-workout use, while research on administering red light therapy duringexercise remains limited.
• When applied before training, the most effective window appears to be 3–6 hours prior, based on the data available so far. This guideline may evolve as future studies refine the understanding of timing and physiological response.

These patterns offer a useful foundation, even as the field continues to develop with new research.

• Near-infrared wavelengths appear to hold a slight advantage. Direct comparison studies between red and near-infrared are limited; most research combines them (red + NIR), and there are virtually no trials isolating each one against the combined approach. Because the majority of performance-related studies have used near-infrared—and given its deeper tissue penetration—devices with a higher proportion of NIR currently seem to offer a small edge.
• There is no universally agreed-upon protocol for red light therapy used before or after workouts. A practical approach is to rely on established dosing principles, keeping applications at up to 60 Joules, and following general best practices for consistent, safe use. Common-sense implementation remains essential as the scientific community continues refining these guidelines.
• Red light therapy influences workout performance through a wide spectrum of biological pathways. These range from enhancing mitochondrial efficiency to improving circulation and reducing muscle damage. Many additional mechanisms are likely still unidentified, meaning the scientific picture will only grow more intricate as research advances.
• Because so many systems are involved, the list of potential benefits is extensive when using red light either before or after workouts. As outlined in the systematic review section, these advantages include reduced muscle soreness and discomfort, improved mitochondrial function, greater gains in strength, endurance, and muscle mass over time, increases in bone density, and more.
• In most cases, combining red light therapy withexercise produces the strongest results. Using only red light therapy or only training tends to yield less impressive outcomes compared to pairing the two.
• A large portion of the existing research uses contact-basedapplication methods and relies more heavily on laser devices than LEDs. Encouragingly, an increasing number of LED-focused studies are emerging, and their results are consistently positive, reinforcing that LEDs are effective rather than lasers alone. One point worth noting is that the commonly cited “20 mW/cm² optimal dose” may not be universally applicable, as many successful laser studies use higher power densities.
• As with most developing fields, additional human research is essential, and this area is no exception.
• Other Strategies to Support Workout Recovery. Red light therapy should be viewed as one tool within a much larger recovery toolkit. While using it before or after training can offer clear benefits, it is not a stand-alone solution. Recovery is influenced by many variables, and several additional strategies can meaningfully support progress, as noted in the introduction of this article.

Final Thoughts: Let Common Sense Lead the Way

The most practical takeaway is this: use a moderate dose of up to 60 J, applied 3–6 hours before training, and be sure it includes near-infrared light. And it’s important to note that research more frequently features 808, 810, and 830 nm, all of which appear highly relevant for performance support.