Red light therapy has become popular for skin, pain, exercise performance, and “longevity.” It is sometimes marketed as a cure-all, which creates unrealistic expectations. In reality, we are talking about photobiomodulation: using light in specific ranges to trigger modest, measurable biological changes in certain tissues. The key is knowing what it is, what it is not, and how to apply it safely.
What red light therapy is (and near-infrared)
Light is energy that travels as waves. In the visible spectrum, red light roughly spans 620–780 nm. Many protocols also include near-infrared light (around 790–1400 nm), which you cannot see but may penetrate tissue a bit more.
In practice, a panel or device emits a relatively narrow band of red and/or near-infrared light, and you expose a body area for minutes at a specific distance.
Why wavelength matters
Two ideas help filter marketing:
- Shorter wavelengths (more “blue”) often carry more energy per photon but penetrate less.
- Red and near-infrared tend to penetrate more, but that does not mean they reach “deep” everywhere or that all tissues respond the same way.
How it might work: chromophores and mitochondria
For a biological effect, light must be absorbed by photosensitive molecules called chromophores. One frequently cited target is cytochrome c oxidase, part of the mitochondrial electron transport chain.
In some experimental models, exposure to red/near-infrared light correlates with changes in mitochondrial activity and cellular energy availability (ATP). Researchers also study downstream signals related to inflammation, oxidative stress, and local blood flow. Important: a plausible mechanism does not guarantee a clinical benefit in humans. Outcomes depend on the specific problem, dose, and consistency.
What evidence suggests by goal
Evaluate this therapy by use cases, not global promises.
Skin: inflammation, texture, and wound support
Evidence varies, but this is one of the most studied areas in clinical settings:
- Support for superficial wound healing and tissue recovery.
- Reduced local inflammation in certain protocols.
- Modest improvements in redness or texture in some studies.
Do not expect dramatic changes within days. If it helps, improvement is usually gradual.
Musculoskeletal and chronic pain
Some people report improvement in joint or muscle pain. Studies suggest potential benefit in certain scenarios, but results vary widely:
- Not all pain types respond.
- Location matters (more superficial vs. deeper targets).
- Per-session dose differs greatly across studies.
Performance and recovery
Protocols before or after training are studied for fatigue and recovery. If there is an effect, it is typically small and does not replace fundamentals: sleep, training programming, adequate protein, and stress management.
Hair
In androgenetic alopecia, light-based devices show mixed results. It may serve as a complement for some people, but it requires months and does not replace a dermatology evaluation.
Eyes and brain: be cautious
Exposure near the eyes requires care. Near-infrared being invisible does not make it harmless. If you use facial panels, prioritize eye protection and avoid aiming directly into the visual field.
Dose: what is often missing
With photobiomodulation, “having a device” is not enough; dose matters.
Useful concepts (without overengineering):
- Irradiance (mW/cm²): how much power reaches the skin at a given distance.
- Time: minutes per session.
- Energy delivered (often J/cm²): irradiance multiplied by time.
More is not always better. Some responses can follow a U-shaped curve: too little does nothing, a moderate dose helps, and too much adds no benefit or may irritate.
Safety: how to use it responsibly
Safety is not only about avoiding burns; it also means avoiding unnecessary or misdirected exposure.
Practical rules
- Protect your eyes when using it on the face or near your visual field.
- Start lower: short sessions first, then increase gradually.
- Avoid excessive heat: if the device gets hot, increase distance or reduce time.
- Do not use on suspicious lesions without medical evaluation.
Medication and sensitive skin precautions
Some medications and dermatologic treatments increase photosensitivity. If you are on photosensitizing medication, have had recent skin procedures, or have a history of skin cancer, ask a clinician before using it.
Choosing a device without falling for hype
Look for clear specifications, not just claims:
- Wavelength (nm) and whether it combines red and near-infrared.
- Irradiance measured at realistic distances (not pressed against the panel).
- Coverage area and emission consistency.
- Electrical certifications and build quality.
A minimal, realistic trial routine
If you decide to try it, run a 6–8 week experiment:
- 3–5 sessions per week.
- 5–12 minutes per area (based on tolerance).
- Fixed distance (mark the floor or use a consistent reference).
- Simple tracking: pain 0–10, stiffness, skin changes, sleep quality, and recovery.
If you notice no meaningful change by the end, it is probably not a high-priority tool for you.
Conclusion
Red light therapy can have real applications, especially for skin and certain pain contexts, but it is not magic. Use it as a complement with moderate expectations, attention to dose, eye protection, and enough consistency to judge whether it adds value.
Author/Source: PeterAttia