Free 7-day Glow-Up Start the challenge →

red light-therapy

Red Light Wavelengths Explained: 630nm vs 660nm vs 850nm

The numbers on the box actually matter. Here's what each wavelength does, which ones you need, and the marketing speak to ignore.

· 4 min read

Heads up: this post has affiliate links. We may earn a small commission if you buy something, at no extra cost to you. We only link to stuff we'd actually tell a friend about. Prices shown are approximate and change often; check the retailer for current pricing.

The short answer

630-660nm (red) penetrates 5mm and treats epidermis/upper dermis (fine lines, tone, surface pigmentation. 810-850nm (near-infrared) penetrates 10mm+ and treats deeper tissue) collagen density, firmness, scars. The best devices combine both.

Every red light device lists wavelengths. Most buyers have no idea what they mean. Here’s the actual science.

The depth-per-wavelength chart

The short answer

Shorter wavelengths (blue, UV) penetrate barely 1mm. Visible red (630-660nm) reaches 5mm. Near-infrared (810-850nm) reaches 10mm+. Choose wavelengths based on what tissue depth you want to target.

Wavelengths and what they do
Product Depth Main effect Rating Where
Visible 415 nm (Blue) <1mm Kills C. acnes bacteria, treats active acne Acne only -
Visible 630-660 nm (Red) ~5mm Boosts ATP, reduces inflammation, fine lines Anti-aging -
Invisible 810-850 nm (NIR) ~10mm Deep collagen synthesis, firmness, scars Deep aging -
Invisible 1064 nm ~30mm Muscle recovery, joint pain, systemic Body, not skin -

630nm vs 660nm: is there a real difference?

The short answer

Both 630nm and 660nm are absorbed by the same mitochondrial enzyme (cytochrome c oxidase) with nearly identical efficiency. 660nm penetrates slightly deeper. For skin, either works, the marketing war between them is mostly noise.

In peer-reviewed literature:

  • 633nm: used in Omnilux clinical trials
  • 660nm: more common in panels; used in wound-healing research
  • Difference in outcomes: minimal when dose is matched

If a device offers 633nm or 660nm and you’re choosing, don’t agonize. Pick on irradiance, FDA clearance, and form factor instead.

Near-infrared is the one people skip: and shouldn’t

The short answer

Near-infrared wavelengths (810-850nm) penetrate into the deeper dermis where collagen remodeling actually happens. Devices without NIR only treat the surface, missing the structural changes that produce long-term firmness.

If you can only pick one wavelength range for anti-aging, pick NIR. Surface benefits (tone, texture) are nice, but the thing that keeps skin looking young is dermal collagen density, and that lives at 10mm down.

Watch out for devices that only offer red (like the Dr. Dennis Gross FaceWare Pro, which uses 605nm red + blue). They work for some things, but they don’t hit deep tissue.

What wavelengths to avoid hype about

The short answer

Avoid devices marketing “400-1000nm full spectrum”, this is usually a single cheap LED emitting broadband light at low intensity. Specific narrow-wavelength LEDs (±10nm) deliver way more therapeutic dose per watt.

Marketing red flags:

  • “Full spectrum” or “400-1000nm range”
  • “7 colors of light therapy”
  • “Includes green, yellow, and purple”
  • Green, yellow, purple LEDs don’t have published skin benefits at consumer doses

Stick with: 630-660nm + 810-850nm. Period.

Devices with the right wavelength combos

Best wavelengths

Dr. Dennis Gross

DRx SpectraLite FaceWare Pro

~$455

FDA-cleared red + blue LED mask. 100 red and 62 blue lights for firmer, clearer skin.

Best for: Evidence-based anti-aging

"A clinically tested at-home LED mask you can use hands-free."
Check price on Amazon →
Best value
~$200

660nm + 850nm. Clean dual-wavelength panel.

Best for: Budget full-body treatment

"Wavelengths are spot-on. That's 80% of what matters."
Check price on Amazon →

Frequently asked

Is 660nm better than 630nm? +

Slightly deeper penetration, but the difference is small. Both are well-studied for skin. Pick based on the full device, not this spec alone.

Do I need near-infrared for face? +

For anti-aging, yes, NIR reaches the dermis where collagen lives. Red-only is fine for tone/texture but limited for firmness.

What do the multi-color "LED therapy" devices actually do? +

Red (630nm) and NIR (850nm) are evidence-based. Blue (415nm) helps acne. Green, yellow, purple are marketing, they don’t have meaningful published skin benefits.

Related: The mask that covers all four of these wavelengths in one device is our Editor’s Pick, see the MitoGLOW vs Omnilux breakdown and the full LED mask shootout.

Keep reading

All articles →

Premium Beauty

More Premium Beauty picks

If money isn't the object, these are our Premium Beauty favorites.

The Glow-Up · free challenge

Get the free 7-day Glow-Up

A 7-day challenge to fix your skincare, tretinoin, SPF, red light, the lot. Then one email a week: what's worth buying, a dupe of the week, and the occasional rant. No BS.

Free. Unsubscribe any time. We never sell your data.