The proven effects of photobiomodulation
How does photobiomodulation work at the cellular level?
The mechanisms of action of photobiomodulation (PBM) are based on the interaction between light and intracellular structures, in particular mitochondria. When red or infrared light (often between 600 and 950 nm) penetrates tissues, it is absorbed by chromophores, notably cytochrome c oxidase, a key enzyme in the mitochondrial respiratory chain. This interaction triggers a powerful biochemical cascade:
Increase in
ATP
(adenosine triphosphate),
the cell's energy molecule.
Modulation of oxidative stress
via regulation of free radicals (ROS) and activation of transcription factors such as NF-κB and HIF-1α, which induce the release of growth factors (VEGF, TGF-β, IGF-1).
Activation of mesenchymal stem cells
promoting tissue regeneration.
These mechanisms explain the multiple effects observed with PBM: anti-inflammatory, analgesic, healing, neuroprotective, angiogenic and even immunomodulatory.
Significant reduction in inflammation
A randomized controlled clinical trial on Achilles tendonitis demonstrated that the application of a 904 nm laser with a fluence of 5.4 J per point significantly reduced the concentration of prostaglandin E2 (PGE2), a key inflammatory marker, up to 105 minutes after treatment. Pain pressure increased significantly in the treatment group, with an average difference of +0.4 kg/cm².
Study based on: Br J Sports Med 40 / 2006, Bjordal JM, Lopes-Martins RA, Iversen VV
Accelerated healing and tissue regeneration
In an in vitro study on a diabetic wound model, WS1 fibroblast cells exposed to a He-Ne laser at 632.8 nm with a fluence of 5 J/cm² showed complete wound closure in 4 days, compared with incomplete closure with 16 J/cm², and significant stimulation of cell migration, without genetic toxicity.
Photobiomodulation has also been successfully used to treat diabetic ulcers (accelerated neo-vascularization and increased collagen production), post-surgical skin lesions and chronic venous lesions.
Study based on: Photomed Laser Surg / April 2007, Houreld N, Abrahamse H
Vaginal dryness and atrophy: clinical results in gynecology
A pilot study on 20 women with vaginal dryness showed that intravaginal photobiomodulation treatment improved vaginal vascularization by +34.6%, lubrication by +94.6% and reduced pain by -79.5%, with no side effects or pain reported.
Study based on: Aesthetic Medicine / Volume 5 / Nº4 / October - December 2019, Pablo Naranjo García, Rodolfo López Andrino, Carlos Gómez González, Hernán Pinto
Photobiomodulation and hair loss: a visible increase in hair density
In patients with androgenetic alopecia, a helmet combining low-intensity laser, LED and magnetic field resulted in an increase in hair density and an improvement in cumulative hair thickness of +37.8% with no adverse effects.
Study based on: Aesthetic Medicine / Volume 5 / Nº4 / October - December 2019, Pablo Naranjo García, Rodolfo López Andrino, Carlos Gómez González, Hernán Pinto
The benefits of photobiomodulation on the skin and skin aging
The skin is one of the most reactive tissues to photobiomodulation. When exposed to specific wavelengths, notably in the red (around 660 nm) and infrared (around 830 to 850 nm), it responds by activating its deep biological mechanisms. Research has shown that PBM stimulates collagen production, improves the quality of elastin fibers and promotes better vascularization, resulting in a smoother, firmer and more radiant skin texture. It helps reduce the appearance of fine lines and wrinkles, while accelerating the healing of skin lesions.
PBM effectively reduces redness, irritation, edema and feelings of discomfort by regulating the local inflammatory response. It is ideally suited to sensitive or mature skin, but also accompanies acne or rosacea therapies, offering a gentle, painless alternative with no side effects.
Study based on: Journal of Clinical Laser Medicine & Surgery / Volume 19 / N°6, / December 2001, H. T. Whelan, R. L. Smits, E. V. Buchman and N. T. Whelan
Joint and muscle pain: relief with PBM
Photobiomodulation has proved remarkably effective in the treatment of athletes and musculoskeletal pain, particularly in cases of aches and pains, tendonitis, sprains, low back pain, neck pain and joint pain linked to osteoarthritis. Application of LLLT at 904 nm significantly reduces inflammatory mediators (specifically prostaglandin E2) and improves the pain threshold under pressure, confirming its anti-inflammatory and analgesic effect.
This type of treatment is distinguished by its non-invasiveness, absence of side effects, and ability to stimulate tissue repair processes while reducing oedema and pain. By locally activating the microcirculation and mitochondria of muscle and tendon cells, PBM promotes faster recovery, without the need for systematic drug or infiltrative treatments.
Study based on: Lasers Med Sci / November 2014, Leal-Junior EC, Johnson DS, Saltmarche A, Demchak T. Adjunctive
A safe device with no side effects
All the trials mentioned have confirmed the absence of pain during sessions, no side effects, and excellent tolerance even after several months. This makes PBM particularly suitable for sensitive populations such as the elderly, menopausal women and diabetics.
Photobiomodulation has established itself as the complementary therapy of choice in many clinical indications. Thanks to rigorous scientific studies conducted over more than two decades, it benefits from a solid body of evidence, at both cellular and clinical levels.
The potential of this gentle, natural and innovative therapy continues to grow.
