LED Phototherapy: A Practical Guide to Wavelengths, Effects on the Skin, and Protocols

TL;DR: LED phototherapy uses visible and non-ionizing infrared light to modulate skin processes without heat or damage. Each color (wavelength) interacts with different chromophores (porphyrins, melanin, water, cytochrome c oxidase), achieving effects such as bactericidal action (blue), melanoregulation (green), anti-edema/anti-inflammatory effects (yellow/orange), biostimulation and increased ATP (red), and analgesia/angiogenesis (infrared). It includes indicative protocols by objective (anti-aging, blemishes, acne, rosacea), parameters (J/cm², time, frequency), and contraindications .

Index

1. What is LED phototherapy and where does the light come from?
2. Properties of the waves and the useful spectrum on skin
3. How far do LEDs penetrate?
4. Colors (nm), chromophores and effects on the skin
5. Guiding protocols by objective
6. Key parameters (power, fluence, time, frequency)
7. Contraindications and precautions
8. Equipment: LED booth vs LED mask
9. FAQ
10. Reference

1) What is LED phototherapy and where does the light come from?

Light is energy that travels in waves and is organized into the electromagnetic spectrum . For therapy, we use non-ionizing waves (visible and infrared) emitted by LEDs ( light-emitting diodes ), a semiconductor that, when energized, produces electroluminescence : photons of a specific color (wavelength). In aesthetics, we work with 400–750 nm (visible) and with infrared for deep biostimulation.

2) Properties of the waves and the useful spectrum on skin

• Wavelength (nm): distance between crests/valleys; determines frequency and energy .
• General rule: longer wavelength → lower frequency/energy; shorter wavelength → higher frequency/energy.
• Areas of interest:
• Visible (400–750 nm): violet, blue, green, yellow, orange, red.
• Infrared: >750 nm (up to ~10,000 nm in the PDF material).
• Non-ionizing (visible/IR) vs. ionizing (UV, X-rays, gamma). For LED therapy, we use non-ionizing light .

3) How far do LEDs penetrate?

Penetration increases from violet/blue → red → infrared . The PDF schematically represents target layers (epidermis, papillary/reticular dermis, adipose tissue) and locates chromophores: porphyrins, keratinocytes, melanocytes, fibroblasts, mitochondria (ATP) , etc.

4) Colors (nm), chromophores and effects on the skin

Violet (400–450 nm)

Effects: Increases ATP , oxygenation, and metabolism; bactericidal (anti-acne); combines the benefits of blue and red light. Note: This is the boundary before UV light; higher energy. Epidermal action.

Blue (450–495 nm)

Bactericidal/fungicidal , sebum-regulating , ↑ hydration . Key mechanism: inactivates Cutibacterium acnes through porphyrins which, upon absorbing blue, generate reactive species that degrade bacteria and reduce inflammation . Strengthens the skin barrier (keratin/lipids), ↑ filaggrin and hygroscopic amino acids. Epidermal action.

Green (495–570 nm)

Melano-regulator , healing/regenerating , reduces pigmentation and irritations; increases collagen / hyaluronic acid / growth factors . Epidermal action.

Yellow (570–590 nm)

Increases dermal proteins , provides a lifting effect , reduces edema (drainage/lymphocytes), controls melanogenesis , and prevents post-inflammatory hyperpigmentation . Useful in inflammatory conditions (rosacea, post-procedure). Superficial papillary dermal action.

Orange (590–620 nm)

Anti-inflammatory , reorganizes dermal proteins , improves capillary fragility , redness and turgor . Superficial papillary dermal action.

Red (620–750 nm)

Mitochondrial biostimulation (↑ ATP ), healing/regenerative , decongests and reduces inflammation ; mild vasodilation → ↓ redness. ↑ mitosis of keratinocytes, collagen and hyaluronic acid . Epidermal and reticular dermal action.

Infrared (>750 nm)

Deep biostimulant , analgesic/anti-inflammatory , angiogenesis , permeabilizes tissue for increased absorption of active ingredients. Acts on the epidermis, dermis, and adipose tissue ; the PDF classifies it as having a thermal effect .

Key cellular pathway (red/IR): activation of cytochrome c oxidase → ↑ ATP , modulation of ROS/NO , ↑ circulation and ↓ edema → ↑ fibroblasts, collagen/elastin , tone and sagging control.

5) Guiding protocols by objective

Note: All steps, times and doses (J/cm²) are taken from the PDF and are intended as a guide within the aesthetic booth.

Blue 10 min (5 J/cm²) → enzymatic 10' → Red 10 min (10 J/cm²) → ceramides/allantoin/“aquaporins” serum → cream with phospholipids/vitamin AE/collagen and massage 5–7' → Yellow 10 min (10 J/cm²) + Orange 10 min (10 J/cm²) → SPF 50+. Note: All steps, times and doses (J/cm²) are taken from the PDF and are intended as a guide within the aesthetic chamber.

Anti-aging

Blue 5 min (5 J/cm²) → enzymatic peeling 10' → RF/Dermapem → Red 10 min (20 J/cm²) + Yellow 10 min (20 J/cm²) → anti-aging emulsion → SPF 50+.

Spots / Melasma

Blue 5 min (5 J/cm²) → enzymatic peeling 10' → depigmenting blend (kojic, phytic, uva ursi) + tranexamic acid (10' each) → Green 15–20 min (10 J/cm²) + Yellow 15–20 min (10 J/cm²) → depigmenting (niacinamide, emblica, kojic) → SPF 50+.

Inflammatory acne (papules/pustules)

Blue 5 min (5 J/cm²) → salicylic 2–10% + enzymatic 5–10' → extractions → Blue or Violet 7–10 min (7 J/cm²) → Red 20 min (20 J/cm²) → sebum-regulating emulgel → SPF 50+ (dry touch).

Sebum regulation / Pores / Comedones

Blue 5 min (5 J/cm²) → abrasive/keratolytic mask + salicylic; dermaplaning/microderm; mandelic 10% 5–10' → Blue + Violet 10+10 min (15 J/cm² each) → sebum-regulating emulgel → SPF 50+.

Rosacea / Sensitive Skin

Blue 5 min (5 J/cm²) → enzymatic 10' → Yellow 15 min (10 J/cm²) → gauze with decongestant agents 10–15' → Green 10 min (10 J/cm²) → decongestant emulsion → SPF 50+.

Dry / dehydrated / devitalized skin

Blue 10 min (5 J/cm²) → enzymatic 10' → Red 10 min (10 J/cm²) → ceramides/allantoin/“aquaporins” serum → cream with phospholipids/vit AE/collagen and massage 5–7' → Yellow 10 min (10 J/cm²) + Orange 10 min (10 J/cm²) → SPF 50+.

6) Key parameters (from the PDF)

• Equipment power: 20 mW to 100 W/mW (depending on equipment); lower power means less penetration.
• Energy density (fluence): J/cm² ; indicative values ​​from the PDF:
• • Anti-aging 15–25 J/cm²
  • Decongestion 10–15 J/cm²
  • Depigmentation 15–25 J/cm²
  • Anti-acne/sebumregular 15–25 J/cm²
• Frequency of application: 1 time/week , ≥10 sessions .
• Exposure time: 5–20 min .
• LED pulse frequency: 1–1000 Hz (low frequencies).
• Adjustment by phototype: I–III 10–100% intensity; IV–VI 10–50% .

7) Contraindications and precautions

Do not apply in: cancer , glaucoma , recent use of isotretinoin/tretinoin (wait 3 months ), post-toxin/fillers (<1 month), hyperthyroidism in the neck , cardiac disorders/pacemaker , infections , pregnancy , epilepsy .
Eye use: Caution with blue light due to potential eye damage/light pollution; use eye protection .

8) Equipment: LED booth vs LED mask

• Booth: more power , more LEDs , less time ; allows combining colors ; no currents.
• Mask: moderate power, fewer LEDs, requires more time ; may incorporate micro-electrostimulation ; usually without simultaneous color mixing .
  The PDF shows controls for intensity , time , continuous/pulsed modes, and color(s) selection .

9) FAQ

Does LED heat up or is it ablative?
The material describes LED as non-coherent, non-collimated, diffuse and polychromatic , with surface work without generating heat; infrared is classified there with thermal action and deep biostimulation.

What color should I use for…?

• Acne: Blue/Violet (bactericidal) + Red (repair).
• Spots: Green (melanoma regulator) + Yellow (anti-inflammatory).
• Rosacea: Blue/Yellow/Green (decongestion).
• Anti-aging/stretch marks/sagging: Red ± IR ; support with Yellow/Orange .

Can I use LEDs after other procedures?
The PDF suggests LED light (especially red/yellow ) after radiofrequency, dermapen, dermaplaning, microdermabrasion, plasmapen, and after peels (depending on concentration and neutralization). Avoid applying LED light over physical masks (they scatter photons).

10) Reference

Arguello, G. (ARVAN Capacitaciones). LED Phototherapy — presentation (2021). All content on this blog comes solely from this PDF.