How far does each colour go?
Choose a wavelength and watch the light travel down into the skin. This is the first thing to understand: a 'red' lamp and an 'infrared' lamp do not work at the same level of the body.
Visible red reaches the dermis: skin, microcirculation, superficial nerve endings.
Depths are orders of magnitude: they vary according to the area, the pigmentation and the power of the source.
Stronger is not better
This is the most counter-intuitive feature of photobiomodulation: the response is not proportional. Too little light does nothing, too much light causes the effect to fall away. Researchers call this the biphasic dose response.
Within the most studied order of magnitude for superficial tissues.
These reference points apply to skin and superficial tissues. The deeper the target tissue, the higher the dose at the surface must be for enough of it to reach the right place — this is where near-infrared becomes indispensable. The exact setting depends on the device: always refer to its instructions.
Moving back 10 cm changes everything
Light disperses as it travels further away. Doubling the distance does not halve the power, it divides it by four. This is the number one reason why two people with the same device do not obtain the same result.
Reference: the power measured at 15 cm, the most common distance of use. At 15 cm, 100% of it remains: the session must be 1.0× longer to deliver the same dose.
True or false?
Six statements you often hear. Click to flip the card.
What we are asked most often
How many sessions before feeling anything?
It depends entirely on what you are looking for. For muscle comfort after exercise, the effect is often perceived from the very first sessions. For skin quality, the studies reporting measurable changes generally run over 8 to 12 weeks, at 3 to 5 sessions per week. Regularity matters more than the length of each session.
Does it tan or damage the skin?
No. Tanning and skin damage are caused by ultraviolet light, below 400 nm. Photobiomodulation devices do not emit any: they work between 600 and 900 nm, at the other end of the spectrum. Indeed, it is red light that is being studied for skin comfort after sun exposure.
Should the eyes be protected?
Intense red light is dazzling and uncomfortable; powerful panels are supplied with goggles. The simple rule: never stare directly at a light source, and follow the device instructions. For a session on the face, close your eyes or wear the goggles supplied.
Are there situations where it is better to abstain?
Yes, and we prefer to say so clearly. In case of pregnancy, photosensitising medication (certain antibiotics, certain dermatological or anticancer treatments), photosensitive epilepsy, an unidentified skin lesion or active cancer, the question should be raised with a doctor before using a device — not with a seller. These devices are wellbeing products: they replace neither a diagnosis nor a treatment.
LED or laser light: what is the difference?
Lasers emit coherent, highly concentrated light, used in clinics on small areas. LEDs cover large surfaces at more moderate power: this is what makes home use possible. Recent literature suggests that, at comparable dose and wavelength, laser coherence is not the determining factor for most superficial applications.
And far infrared, saunas, textiles?
That is another register. Beyond 3000 nm, radiation is absorbed by the water in tissues and turns into heat: this is radiant heat, pleasant and vasodilating, but the mechanism is no longer cellular photobiomodulation. The two approaches complement each other; you simply need to know which one you are buying.
Now to choose the right device
Now that the basics are set out: tell us what you are aiming for, and we will point you towards the format and wavelengths that match — with the price.