FAQ
1. What is photbiomodulation / red light therapy?
Photobiomodulation - also known as red light therapy - is a form of therapy that uses red light and near-infrared licht to influence biological processes in the body. The treatment is carried out using lasers or LED light resources.
2. How does red licht therapy work?
Light is absorbed in the mitochondria, the cell’s energy centers, by an enzyme called cytochrome c-oxidase. This improves oxygen uptake and increases production of ATP, the cell’s energy currency. It also triggers the release of nitric oxide, which can improve blood flow, and produces low concentrations of reactive oxygen species (ROS) that act as signaling molecules and can kick-start repair processes.
3. How and by whom was red light therapy discovered?
Red light therapy was discovered by accident in 1967 by the Hungarian physician and researcher Endre Mester. He was studying the effects of laser light on cancer in mouse models and noticed that low-power laser light stimulated hair growth and wound healing in the treated skin.
4. What is red light therapy used for?
5. What is the difference between laser and LED light?
The wavelengths of laser and LED light are the same, but because laser light is coherent and focused, it can reach a higher power density (mW/cm²) than LED light. LED light is incoherent, spreads out more, and has lower power, which generally makes it safer for consumer use.
6. Which wavelengths are used, and for what?
Red light (around 630–670 nm) is mainly used for surface-level applications, like the skin. Near-infrared light (around 810–1090 nm) penetrates deeper and is often used for muscles, tendons, nerves, and the brain.
7. Is red light therapy the same as an infrared sauna?
No. Infrared saunas use far-infrared (FIR) light with a much longer wavelength, and its effect is mainly thermal. PBM uses red and near-infrared light and works through different, cellular mechanisms.
Does red light therapy also have systemic effects?
Research shows PBM can have systemic effects — effects that extend beyond the area exposed to light. In one animal study, an unexposed leg healed faster when the other leg was treated. In humans too, effects have been observed outside the treated area — for example on blood sugar levels after exposing the back, and on depression when PBM was applied for other indications.
9. How do you calculate the red light therapy dose?
Dosage is expressed in J/cm² and calculated as power (mW/cm²) multiplied by exposure time (seconds), divided by 1000.
10. Is red light therapy safe? What are the side effects?
There is no evidence that PBM causes cancer or stimulates tumor growth, but caution and medical monitoring are recommended for existing tumors. Not enough is known yet about use during pregnancy, so caution is advisable. Diabetes is not a contraindication, but since PBM can affect blood sugar levels, monitoring may be wise — especially when treating larger body surfaces.
There is no evidence that PBM causes cancer or stimulates tumor growth, but caution and medical monitoring are recommended for existing tumors. Not enough is known yet about use during pregnancy, so caution is advisable. Diabetes is not a contraindication, but since PBM can affect blood sugar levels, monitoring may be wise — especially when treating larger body surfaces.
Are you pregnant, do you have a medical condition, or do you want to use red light therapy for something other than the condition you’re being treated for? Always consult a doctor first.
11. Can too much red light therapy be harmful?
Red light therapy follows a biphasic effect: too little light has no effect, the right dose stimulates cells, but too much light can actually backfire through oxidative stress. te weinig licht heeft geen effect, een goede dosis stimuleert cellen, maar te veel licht kan juist averechts werken door oxidatieve stress.
12. Are there situations requiring extra cautrion when applying red light therapy?
There is no evidence that PBM causes cancer or stimulates tumor growth, but caution and medical monitoring are recommended for existing tumors. Not enough is known yet about use during pregnancy, so caution is advisable. Diabetes is not a contraindication, but since PBM can affect blood sugar levels, monitoring may be wise — especially when treating larger body surfaces.
Are you pregnant, do you have a medical condition, or do you want to use red light therapy for something other than the condition you’re being treated for? Always consult a doctor first.
13. Why is red light therapy rarely used in manistream healthcare?
Despite more than 7,000 studies — in vitro, in animals, and in humans — large-scale, standardized human trials are still lacking. Studies use varying wavelengths, devices, and protocols, making results hard to compare. Not all relevant parameters are always reported either. As a result, there is currently insufficient evidence for many applications to include PBM in medical guidelines.
This website is intended for orientation purposes for healthcare providers and does not replace medical advice. If you are pregnant or have a medical condition and are considering using PBM, discuss this with a doctor first — even if you intend to use PBM for a different complaint or application..