The Complete Guide to Light Therapy: From UV to Infrared - Unlocking the Healing Power of Every Wavelength
TL;DR: Your Complete Light Therapy Spectrum
The bottom line: Light therapy harnesses specific wavelengths from 280nm to 1000nm+ to treat conditions ranging from acne and psoriasis to depression and chronic pain. Each spectrum has unique biological effects: UV light produces vitamin D and treats autoimmune skin conditions, blue light kills acne bacteria, green light reduces inflammation, yellow light stimulates lymphatic drainage, red light boosts collagen production, and near-infrared penetrates deepest for cellular healing and pain relief.
Light isn't just illumination—it's medicine. For over a century, researchers have discovered that specific wavelengths of light can trigger profound healing responses in human tissues, from the surface of the skin down to the cellular level.
While red and near-infrared light therapy have gained the most attention recently, the full electromagnetic spectrum offers a treasure trove of therapeutic possibilities. From ultraviolet rays that treat autoimmune conditions to green light that calms inflammation, each wavelength operates through distinct biological mechanisms.
This comprehensive guide explores every therapeutic wavelength, backed by clinical research, so you can understand which light therapy modalities might benefit your specific health goals.
Understanding the Light Spectrum: How Wavelength Determines Function
The electromagnetic spectrum visible to humans spans approximately 380 to 800 nanometers (nm), but therapeutic light extends both below and above this range. Different Colors of Light have Different Health Effects, with the energy in light dependent on the wavelength and color being how the human eye and brain understand light's electromagnetic wavelengths.
Key principle: Each color penetrates the skin at different depths. Blue light affects the uppermost layer of your skin. Yellow light penetrates deeper. Red light travels further into your skin. Near-infrared light penetrates deepest.
This depth-dependent action is crucial for understanding which wavelengths to use for specific conditions.
Ultraviolet Light Therapy (280-400nm): The Powerful Medical Tool
Despite its reputation for causing sunburn, controlled UV exposure is one of medicine's most effective treatments for autoimmune skin conditions and vitamin D deficiency.
UVB Light Therapy (280-315nm): The Vitamin D Producer
Primary benefits:
Vitamin D synthesis: UVB light is very biologically active in that it is what helps the body produce vitamin D3, with skin exposed to UVB light in the range of 297 nm transforming cholesterol into vitamin D3, requiring only 50-100 millijoules to generate vitamin D3.
Psoriasis treatment: Typically, patients with moderate-to-severe psoriasis require 20–36 sessions of NB-UVB phototherapy at a frequency of three sessions per week to see significant improvement, with clearance rates often reported to be in the 60–70% range.
Immune regulation: UV exposure can suppress overactive immune responses in autoimmune conditions
Clinical applications:
Psoriasis (most effective treatment available)
Vitiligo
Eczema/atopic dermatitis
Seasonal Affective Disorder
Vitamin D deficiency
Safety considerations: Studies show that UVB treatment is effective when used for treatment of vitamin D deficiency, psoriasis and other conditions, but more importantly they show that it's safe – even with prolonged use.
UVA Light Therapy (315-400nm): The Deep Penetrator
PUVA therapy combines UVA with psoralen (a light-sensitizing medication):
PUVA slows down excessive skin cell growth and can clear psoriasis symptoms for varying periods of time, with stable plaque psoriasis, guttate psoriasis, and psoriasis of the palms and soles being most responsive to PUVA treatment.
More intensive than UVB but with higher side effect risk
Reserved for severe, treatment-resistant conditions
Blue Light Therapy (400-500nm): The Acne Destroyer
Blue light represents the shortest wavelength in the visible spectrum and has become the gold standard for acne treatment.
Mechanism of Action
Blue LED light therapy may destroy acne-causing bacteria (P. acnes). The bacteria that cause acne produce porphyrins, which absorb blue light and create reactive oxygen species that kill the bacteria.
Clinical Effectiveness
A clinical-strength study found that by week eight of blue light treatments more than 90 percent of subjects reported improvements in their skin's overall appearance, clarity, radiance.
Optimal parameters:
Wavelength: 415nm (most bactericidal)
Treatment time: 15-20 minutes
Frequency: Daily for acute treatment, 2-3x weekly for maintenance
Additional benefits:
Blue light therapy specifically targets bacteria to treat acne and can regulate oil production
Non-invasive alternative to antibiotics
No bacterial resistance development
Green Light Therapy (500-565nm): The Anti-Inflammatory Healer
Green light therapy is emerging as a powerful anti-inflammatory treatment with unique applications in pain management and skin healing.
Research-Backed Benefits
Green light has a lot of potential as it may work as an anti-inflammatory, stimulate blood vessel synthesis, and promote the healing process, with one study suggesting green light may play a role in new blood vessel formation as well as a promising role in tissue regeneration.
Migraine Treatment Breakthrough
In 2023, a mass online statistical review collected data from 181 participants using green light–emitting lamps at home for treating migraines, with data suggesting that two hours of treatment during migraine attacks is associated with relief of pain and photophobia, reduction in anxiety, and improved sleep.
Clinical applications:
Migraine relief
Inflammatory skin conditions
Wound healing acceleration
Rosacea and skin redness
General pain management
Treatment protocol:
Wavelength: 525-530nm optimal
Duration: 30 minutes to 2 hours depending on condition
Frequency: Daily during acute episodes
Yellow/Amber Light Therapy (570-590nm): The Lymphatic Stimulator
Yellow light therapy works at the intersection of skin healing and systemic detoxification.
Primary Functions
Yellow light stimulates circulation, aids in the removal of toxins and waste products from your skin, can lead to a clearer complexion, reduced puffiness, and a healthier glow.
Melanin Regulation
Yellow light fights hyperpigmentation at the source, reducing the production of a necessary amino acid (tyrosinase) for melanin synthesis as well as stopping melanosomes from maturing.
Benefits:
Lymphatic drainage enhancement
Hyperpigmentation reduction
Post-laser healing acceleration
Improved circulation
Skin detoxification
Research validation: One study proved that 590 nm light therapy after laser skin treatments reduced the intensity and healing time of skin irritation.
Red Light Therapy (630-700nm): The Collagen Booster
Red light therapy has the most extensive research base and broadest range of applications.
Cellular Mechanisms
Red LED light therapy may reduce inflammation and stimulate the production of collagen, a protein responsible for younger-looking skin that diminishes with age.
Anti-Aging Effects
By stimulating the mitochondria, red light enhances collagen production, which helps with anti-aging or skin that has suffered sun damage.
Clinical applications:
Wrinkle reduction and skin tightening
Wound healing acceleration
Hair growth stimulation
Muscle recovery
Joint pain relief
Seasonal depression
Optimal parameters:
Wavelength: 660nm (most studied)
Power density: 20-200 mW/cm²
Treatment time: 10-20 minutes
Frequency: Daily or every other day
Near-Infrared Therapy (700-1000nm): The Deep Tissue Healer
Near-infrared (NIR) light penetrates deeper than any other wavelength, making it ideal for treating internal tissues and systemic conditions.
Penetration Depth
Near-infrared light penetrates deeper into tissues than visible light, with the deeper penetration depth of near-infrared light being one reason why it's utilized in therapeutic applications such as pain management, wound healing, muscle recovery, and skin rejuvenation.
Mitochondrial Enhancement
NIR light directly stimulates cytochrome c oxidase in mitochondria, boosting cellular energy production (ATP) and enhancing the body's natural healing processes.
Clinical applications:
Chronic pain management
Deep tissue injury recovery
Neuropathy treatment
Cognitive enhancement
Circulation improvement
Inflammatory conditions
Treatment protocols:
Wavelength: 810nm, 830nm, or 850nm
Higher power density needed (100-300 mW/cm²)
Longer treatment times (15-30 minutes)
Consistent daily use for chronic conditions
Combination Light Therapy: Synergistic Healing
Many conditions benefit from multi-wavelength approaches that address different aspects of healing simultaneously.
Proven Combinations
Red + Blue combines anti-aging and acne-fighting benefits for comprehensive treatment; Blue + Green calms breakouts and reduces inflammation for clearer, healthier skin; Red + Green tackles both wrinkles and redness, promoting a smoother, more even complexion.
Clinical Evidence
Celluma devices use optimized combinations of blue, red, and near-infrared light simultaneously, so you don't have to choose just one, with this multi-wavelength approach treating multiple skin and health concerns in a single session.
Choosing the Right Light Therapy: A Practical Guide
For Acne and Oily Skin
Primary: Blue light (415nm)
Secondary: Red light (660nm) for inflammation
Protocol: Daily 15-minute treatments for 4-8 weeks
For Anti-Aging and Skin Rejuvenation
Primary: Red light (660nm)
Secondary: Near-infrared (830nm) for deeper penetration
Protocol: Daily 15-20 minute treatments long-term
For Pain and Inflammation
Primary: Near-infrared (810-850nm)
Secondary: Red light (660nm) for surface inflammation
Protocol: 20-30 minute treatments daily
For Seasonal Depression
Primary: Broad-spectrum bright light (10,000 lux)
Secondary: Red light therapy in evening
Protocol: 30 minutes morning bright light, 15 minutes evening red light
For Skin Conditions (Psoriasis, Eczema)
Medical grade: Narrowband UVB (311nm)
Home care: Red + NIR combination
Protocol: Medical supervision required for UV therapy
Safety Considerations Across the Spectrum
UV Light Safety
The UV light used in phototherapy is the same type of light emitted from the sun, with providers controlling the strength of the light and monitoring exposure time to prevent skin damage.
Always requires medical supervision
Eye protection mandatory
Skin cancer risk with excessive exposure
Visible Light Safety
LED light therapy doesn't use ultraviolet (UV) light, so it doesn't cause damage or burns to your skin, and LED light therapy is a safe, relatively risk-free treatment.
Eye protection recommended for bright treatments
No known long-term adverse effects
Safe for daily use
Contraindications
Certain medications increase photosensitivity
History of skin cancer (especially for UV therapy)
Pregnancy (consult healthcare provider)
Epilepsy or light sensitivity disorders
The Future of Multi-Spectrum Light Therapy
As research continues to unveil the therapeutic potential of different wavelengths, we're moving toward personalized light therapy protocols that combine multiple spectrums for optimal healing.
Emerging applications:
Precision wavelength combinations based on genetic testing
AI-driven treatment protocols
Wearable multi-spectrum devices
Integration with circadian rhythm optimization
The Bottom Line: Light as Precision Medicine
Each wavelength in the electromagnetic spectrum offers unique therapeutic benefits, from UV light's ability to reset immune function to near-infrared's power to heal deep tissues. The key is understanding which wavelengths address your specific health goals and using them with appropriate parameters and safety measures.
While red and near-infrared light therapy offer the broadest benefits with the lowest risks, don't overlook the powerful applications of other wavelengths—from blue light's acne-fighting properties to green light's anti-inflammatory effects.
Key takeaways:
Wavelength determines function: Shorter wavelengths affect surface tissues, longer wavelengths penetrate deeper
Combination therapy often superior: Multi-wavelength approaches address multiple healing pathways
Consistency is crucial: Regular treatments yield better results than intermittent high-dose exposures
Professional guidance valuable: Especially for UV therapy and complex conditions
Individual response varies: Start conservatively and adjust based on results
Primary Research Citations:
Cleveland Clinic - LED Light Therapy (Index 53)
Homlyns - LED Light Therapy Color Benefits (Index 55)
Joovv - Wavelength Chart and Health Benefits (Index 59)
Lumivisage - LED Light Therapy Color Benefits (Index 61)
PMC - UVB Phototherapy for Psoriasis (Index 64)
Cleveland Clinic - Phototherapy Medical Uses (Index 63)
Ready to explore light therapy? Start with the safest, most researched wavelengths (red and near-infrared) and consider professional guidance for UV or complex multi-spectrum treatments.