Red light is visible and is absorbed mostly in the layers near the skin's surface; near-infrared lies just beyond what the eye can see and reaches deeper layers. Studies have used each on its own and both together. Use a panel 8–50 cm from the skin, 10–30 minutes a session, at most 30 minutes a day per area.
What is the difference between red and near-infrared light?
Both are bands of light, named by their wavelength in nanometres (nm). Both are non-ionising: they contain no UV and don't tan. On a panel, the near-infrared channel looks much dimmer than the red one, because the eye barely registers it.
Smart Series panels combine six wavelengths in two channels: red at 610, 630 and 660 nm, and near-infrared at 810, 830 and 850 nm. They measure 132–152 mW/cm² at 15 cm (spectrometer-measured). How a panel compares with an infrared heat lamp or sauna is covered in red light vs infrared.
How far into the skin do red and near-infrared light travel?
Mostly, it depends on the wavelength. In a 2017 computer model of light passing through the layers of the skin, penetration depth increased with wavelength across the range it covered, 300–750 nm; at 750 nm, 1% of the light still reached about 5.4 mm (Ash et al.). The authors note that wavelengths above 750 nm, which include the near-infrared bands above, weren't part of the model.
So “deeper” here means millimetres into the skin, and the figure comes from a model, not from measurements in people. What the near-infrared band is used for on its own is covered in near-infrared light therapy, and its longest wavelength in what 850 nm near-infrared does.
Which wavelengths have skin studies used?
In a 2007 split-face study, 76 adults with facial wrinkles had 633 nm red light, 830 nm near-infrared light, both together or a sham light on one half of the face, twice a week for four weeks. Over the study and a three-month follow-up, all three light groups showed measured wrinkle reductions of up to 36% and elasticity gains of up to 19% against their starting values (Lee et al.).
The study put red, near-infrared and the combination side by side; its summary reports the three light groups together and doesn't name one setting as the best.
Which wavelengths have exercise studies used?
A 2016 review gathered 46 studies on light and human muscle, with 1,045 trained, untrained and elite participants. They used red, near-infrared and mixed red and near-infrared light, from single laser probes to flexible LED arrays, and the review sorts their settings into those with and without effects on performance and recovery (Ferraresi et al.).
Red, near-infrared or both: which should you choose?
You don't have to decide when you buy. The two channels are controlled separately, so in each session you can use red only, near-infrared only or both together.
What decides the model is the area you want to cover. The Smart Small suits the face, neck and shoulders on a table stand; the Smart Medium also reaches the back or legs, on a floor stand or wall mount. You can compare them in our panel collection. Both are made by a partner manufacturer to RedLightMed's specification and European (CE) requirements, and every unit is checked in Hungary.
Close your eyes or wear the goggles; there's a pair in every box.
It isn't recommended for children under 12, while breastfeeding, with epilepsy, with known tumours or metastases, or if you're sensitive to light. During pregnancy, only after talking to your doctor.
Sources
Ash C, Dubec M, Donne K, Bashford T. Effect of wavelength and beam width on penetration in light-tissue interaction using computational methods. Lasers Med Sci, 2017. PubMed 28900751
Lee SY, Park KH, Choi JW, et al. A prospective, randomized, placebo-controlled, double-blinded, and split-face clinical study on LED phototherapy for skin rejuvenation … J Photochem Photobiol B, 2007. PubMed 17566756
Ferraresi C, Huang YY, Hamblin MR. Photobiomodulation in human muscle tissue: an advantage in sports performance? J Biophotonics, 2016. PubMed 27874264
