The anchor category
How do you know if it's a real red light therapy wrap, or just a heating pad?
Look for wavelengths in nanometres, a diode count, and an irradiance figure. A wrap that only advertises heat settings, 'infrared warmth' or a temperature in degrees is a heating pad with a red bulb.
Body wraps and belts are the easiest place in this category to sell a heating pad as light therapy. The tell is simple, and it takes ten seconds on any listing.
The three numbers a real device publishes
Wavelength in nanometres: 660 nm red and 850 nm near-infrared are the studied bands. A listing that says 'infrared' with no number usually means far-infrared heat, which is warmth, not photobiomodulation.
Diode count and layout: how many LEDs, spread over what area. Twenty diodes across a 40 cm belt is decoration. A few hundred is a device.
Irradiance, in milliwatts per square centimetre, at a stated distance. Anything from about 20 to 100 mW/cm² at skin contact is in the range trials use. A seller who has measured it will tell you; one who has not will talk about 'powerful therapeutic energy'.
The tells of a heating pad
Temperature settings in degrees, or 'three heat levels', as the headline feature. Heat is pleasant and does help circulation and stiffness; it is not light therapy and should not cost light therapy money.
Photos where the whole panel glows a soft even red through fabric. Real LED arrays show individual points of light.
The phrase 'far infrared'. Far infrared is heat radiation, a completely different part of the spectrum from the 850 nm near-infrared in the studies.
No eye-safety note anywhere. A device bright enough to matter always carries one.
What a real wrap can and cannot do
Can: warm and light the tissue under it, which trials associate with less muscle soreness after exercise, better circulation, and some help with joint stiffness. Can: improve skin texture on the area over weeks.
Cannot: burn fat, 'detox', melt cellulite, or treat any disease. If the claim needs a doctor to make it, the wrap cannot make it.
Red Light Therapy · Questions people actually ask
Straight answers
The listing says 660 nm but the light looks pink. Is it lying?
Not necessarily. Cameras render 660 nm oddly and many wraps mix in 850 nm, which is invisible and shows as a faint glow. Judge it by the published numbers and the diode layout, not by the photo.
Does it matter if I feel heat?
Some warmth is normal, from the diodes themselves. If heat is the main sensation and the light is dim, you bought a heating pad.
Is a cheap wrap useless?
No. Cheap devices with honest specs and a modest dose work slowly. Expensive devices with no published specs are the actual scam.
Updated 2026-09-06. Nothing here is medical advice. A device is never a substitute for a dermatologist.