Mitochondria and photobiomodulation:
the ATP mechanism

Photobiomodulation (PBM) is the technical name for what we commonly call red light therapy. The word sounds complex, but the principle is elegant: light of certain wavelengths "modulates" — gently adjusts — the activity of cells. And it all revolves around the mitochondria.

The history is interesting. The first hints that low-level light could speed up healing appeared as early as the late 1960s. Thousands of studies have followed, and PBM is now studied for muscle recovery, healing, joint pain, skin condition and mental wellbeing. The strength of evidence varies by field, but the biological mechanism is becoming ever clearer.

Step by step: what happens in the cell

Picture a mitochondrion as a miniature power plant. It produces energy in four consecutive stations that form the so-called respiratory chain. Electrons flow through them and, at the end, ATP is produced — the molecule that powers virtually everything the cell does.

• 1. A photon lands on cytochrome c oxidase. This enzyme (the fourth station of the chain) is the cell's main "receiver" of red and infrared light.
• 2. Nitric oxide (NO) is released. Under stress NO binds to the enzyme and brakes it like a handbrake. Light releases that brake.
• 3. The chain speeds up. Electrons flow more efficiently and the mitochondrion makes more ATP.
• 4. Signalling is triggered. Briefly, small amounts of reactive oxygen species also form, acting as a signal — the cell responds by strengthening its defence and repair mechanisms.

Why the wavelength matters

Cytochrome c oxidase absorbs light best in a few narrow bands — around 630–680 nm (red) and 800–860 nm (near-infrared). That is why these wavelengths appear most often in therapy panels. Longer infrared waves (940–1060 nm) penetrate even deeper and contribute to acting on deeper tissue and to a sense of warmth and relaxation.

Combining several wavelengths at once is therefore not marketing — it is an effort to cover different absorption bands and different tissue depths with a single device.

Dose is decisive

With PBM the hormesis principle applies: there is an optimal dose range. Too little light has no effect, too much can reduce it. The dose depends on irradiance (how much energy reaches the surface), distance and time. That is why quality panels state their irradiance at a given distance and recommended session times.

A typical session with red and infrared light lasts a few minutes from about 15–30 cm, several times a week. Consistency tends to matter more than the length of a single session.

What PBM is not

It is fair to say what photobiomodulation is not. It is not a miracle cure and does not replace treatment. It is a tool that supports the body's natural processes — regeneration, energy production, healing. It works best as part of a healthy lifestyle, not instead of one.