When it comes to photobiomodulation (PBM), the overwhelming majority of content circulating on social media talks about post-workout muscle recovery: less fatigue, less delayed onset muscle soreness, and more productive subsequent workouts. It is a real and well-documented use. But it is also just a small fraction of what this technology is capable of doing.
In clinical practice, photobiomodulation, whether with low-level laser, high-power laser or LED, has a robust body of scientific literature in much broader areas: shoulder tendinopathies, osteoarthritis and knee tendinopathy, chronic low back pain, disc herniations, and even myofascial trigger points. And this is precisely where most colleagues fall behind, because the conversation never moves beyond recovery. This leads to the underutilization of equipment, which can generate much greater therapeutic and financial returns.
This article is the starting point for that evolution: a summary of what current scientific evidence says about the therapeutic effects of photobiomodulation on these conditions.
Note: this article is for informational purposes and does not replace an individual clinical assessment. In the event of persistent pain or an injury, always seek guidance from a physiotherapist or another qualified healthcare professional.
Why look beyond recovery?
The true clinical value of photobiomodulation lies in its ability to intervene directly in painful and limiting conditions that prevent a person from training, working, or simply living pain-free. Muscle recovery is also useful and relevant, with PBM being the only non-reactive strategy in that domain by generating muscle protection through increased ATP supply, but it is only a fraction of what the technology has to offer.
This is not a vague promise. It is what dozens of randomized clinical trials and systematic reviews, published in recent years, have been demonstrating: with positive results, but also with inconsistent or even negative results, which are also an honest part of this story. Inconsistencies are always associated with dosing errors, which can be easily resolved with the abundance of existing scientific information.
Does photobiomodulation work for shoulder tendinitis?
Rotator cuff tendinopathy and subacromial impingement syndrome are among the most studied shoulder conditions regarding photobiomodulation. Trials with low-level laser combined with exercise show consistent reductions in pain and improvements in function for calcific tendinitis and supraspinatus tendinitis, even decades after the first controlled studies were published.
High-power laser also presents positive results in this region: in partial supraspinatus tears and subacromial impingement syndrome, several randomized trials show it to be superior to therapeutic ultrasound and to protocols without photobiomodulation, with relevant gains in pain and function (measured by scales such as SPADI or DASH).
Knee: patellar tendinopathy and osteoarthritis
In the knee, photobiomodulation has two very distinct fronts of evidence.
For patellar tendinopathy (the so-called "jumper's knee"), studies with low-level laser show significant improvements in pain and function, especially when combined with eccentric exercise: in one of the reference studies, the combination outperformed both laser alone and exercise alone in most functional measures, although there was no clear difference between the combination and laser alone regarding pain reduction itself. Thus, the analgesic potential of photobiomodulation and the relevance of incorporating it into rehabilitation programs are evident.
In knee osteoarthritis, the evidence is even more extensive: a systematic review with over a thousand participants, distributed across 22 placebo-controlled trials, confirmed statistically robust and dose-dependent pain reductions, which were greater when doses recommended by international literature were followed. High-power laser, when directly compared to low-level laser in several recent meta-analyses, tends to produce greater gains in pain and function after several weeks of treatment, although the two are equivalent in the first few weeks. This information is very important because the investments are drastically different, while the results are very similar.
Lumbar spine: nonspecific chronic pain and disc herniation
Nonspecific chronic low back pain is probably the topic with the most research syntheses published in photobiomodulation, including a landmark Cochrane review. And it is also where the evidence most clearly teaches us not to simplify and not to settle for the basics.
A robust meta-analysis, with virtually zero statistical heterogeneity between studies, found a large and very consistent reduction in pain with low-level laser, but no significant effect on functional disability or spinal range of motion. In other words: photobiomodulation is one part of the treatment, which must be complete and complex, as is the nature of nonspecific low back pain. Once again, the dose is fundamental and must account for individuality.
In lumbar disc herniation, the picture is repeated: reviews show that photobiomodulation works better as a complement to therapeutic exercise programs than it does alone.
Myofascial trigger points: muscle "knots"
Myofascial trigger points, those painful and hyperirritable nodules within a taut band of muscle, so common in the upper trapezius, hamstrings, quadratus lumborum, gluteus medius, and masseter (to name a few) are another fertile ground for photobiomodulation, with an interesting particularity.
A systematic review with nearly a thousand participants concluded that photobiomodulation, combined with exercise, is effective in reducing pain and increasing the pressure pain threshold in the upper trapezius. However, a very recent trial, rigorously placebo-controlled and double-blinded, found no difference in pain between the treated group and the placebo group: it did, however, find a significant improvement in cervical function. This is the reverse of the usual pattern (pain improves, function does not), and it is an excellent example of how a single outcome should never be used on its own to conclude that it "works" or "doesn't work."
Outside of the trapezius, research is scarcer: there is good data for masseter muscle trigger points associated with temporomandibular dysfunction, but practically no evidence for high-power photobiomodulation or pure LED outside the cervical region.
The response depends on how it is applied
There is a principle that runs throughout this context: photobiomodulation is not a single, uniform intervention. Low-level laser, high-power laser, and LED have different mechanisms, penetration depths, and response profiles, and even within the same modality, how it is applied, how much, where, and how often, determines whether there is a real clinical effect. I repeatedly find excellent effects using LED clusters with doses 30 to 40% higher, which is justified by the greater dispersion of LED light. However, the results are there!
This is why the scientific literature in this area has so many apparently contradictory results: often, it is not the technology that fails, but the way it was applied or the absence of a structured treatment plan around it. What we know for sure is that using only one therapeutic resource with a standardized dose will obviously not produce great results. A therapeutic resource can never be the main focus: it is a resource, an auxiliary tool, and a complement to more complex work.
A complement, not a substitute
If there is one idea that is repeated in almost all reviewed studies, it is this: photobiomodulation works best when integrated into an active rehabilitation plan with therapeutic exercise, and not instead of it. In patellar tendinopathy studies, the combination of laser + eccentric exercise outperforms either intervention alone. In knee osteoarthritis, the same pattern repeats. In low back pain, the benefit of the laser is greater when used as an adjuvant than when used in isolation.
Photobiomodulation facilitates the rehabilitation process: it reduces pain, improves exercise tolerance, and creates more favorable conditions for progressive loading. But it is movement, well-dosed loading, and clinical follow-up that do the actual treating. The technology helps; it does not replace.
A consistently positive point
Throughout all this evidence, across shoulder, knee, lumbar spine, and trigger points, one finding remains stable: photobiomodulation is generally safe. Reported adverse events are rare, mild, and transient (typically a sensation of heat or tingling), and none of the studies reviewed reported musculoskeletal damage or serious events associated with the treatment. This does not mean that photobiomodulation is always effective, as we have seen, it is not, but it means that when indicated and correctly applied by a qualified professional, the associated risk is low.
The conversation needs to evolve
Recovery will continue to be, quite rightly, one of the most popular uses for photobiomodulation: it is visible, it is immediate, and it makes sense to those who train. But reducing this technology to recovery is to ignore the most interesting and clinically relevant part of the story: photobiomodulation has a solid place, supported by real science, in the treatment of tendinopathies, osteoarthritis, chronic low back pain, and myofascial trigger points, always with honesty about what works, what works partially, and what still lacks a definitive answer.
