Can infrared or near infrared light therapy restore hair growth?

Infrared and Near-Infrared Light for Hair Restoration

Infrared and near-infrared light therapy shows preliminary evidence for promoting hair regrowth in alopecia areata and androgenetic alopecia, but the evidence remains weak (level 3) and should be considered only as an adjunctive or alternative option when conventional treatments fail or are contraindicated.

Evidence Quality and Limitations

The British Association of Dermatologists guidelines classify laser therapy for alopecia areata as level of evidence 3 (the lowest quality), based on small uncontrolled studies 1. This means:

• No high-quality randomized controlled trials exist
• Studies lack adequate controls and blinding
• Sample sizes are very small (typically 15-44 patients)
• Long-term efficacy and durability data are absent

Specific Evidence for Different Light Modalities

Infrared Diode Laser for Alopecia Areata

• In 16 patients with patchy alopecia areata, complete or partial regrowth occurred in 32 of 34 treated patches, while untreated patches showed no growth 1
• A linear polarized infrared device (Super Lizer) showed hair regrowth in 46.7% (7/15) of irradiated areas, occurring 1.6 months earlier than non-irradiated areas 2
• These studies lack placebo controls and blinded assessment, limiting their reliability

Red/Near-Infrared Low-Level Light Therapy (LLLT) for Androgenetic Alopecia

• FDA-approved LLLT devices exist for hair loss treatment, though approval does not guarantee robust efficacy 3
• A randomized controlled trial in 44 males with androgenetic alopecia using 655 nm red light (lasers + LEDs) demonstrated a 35-39% increase in hair counts versus placebo after 16 weeks of treatment 4
• Another study of 7 patients showed trends toward increased terminal hairs and shaft diameter, but changes were not statistically significant and blinded reviewers found no subjective improvement 5

Near-Infrared for Hair Removal (Not Growth)

• Near-infrared pulsed light is effective for permanent hair reduction, not hair growth, achieving 52-73% hair reduction 6
• This contradicts the therapeutic goal and should not be confused with hair restoration treatments

Clinical Recommendations

When to Consider Light Therapy

For alopecia areata:

• Only after first-line intralesional corticosteroids (62% full regrowth rate) have failed or are impractical 7
• Only for patients unwilling or unable to pursue contact immunotherapy with DPCP 7, 8
• Particularly for patients seeking non-invasive options with minimal side effects 2

For androgenetic alopecia:

• Consider only after minoxidil and finasteride have failed or are contraindicated 3, 5
• May be reasonable for patients refusing hair transplantation 5
• Set realistic expectations: modest improvement at best, not complete restoration 7

Treatment Parameters (When Used)

• Red/near-infrared wavelengths: 655 nm appears most studied 4
• Frequency: Every other day or twice weekly 5, 4
• Duration: Minimum 3-6 months needed to assess response 5, 4
• Energy: Approximately 67 J/cm² per treatment session 4

Critical Caveats

• Spontaneous remission occurs in up to 80% of limited patchy alopecia areata cases within 1 year, making it impossible to attribute improvement to treatment without proper controls 7, 8
• The mechanism of action remains poorly understood despite FDA approval 3
• Cost-effectiveness is unproven compared to established treatments
• Individual response is highly variable and unpredictable 5

Bottom Line Approach

1. First-line treatments remain superior: Use intralesional corticosteroids for alopecia areata or minoxidil/finasteride for androgenetic alopecia 7
2. Consider light therapy only as second or third-line: When conventional treatments fail, are refused, or contraindicated 1, 3
3. Counsel extensively: Explain the weak evidence, variable results, and need for prolonged treatment 5
4. Monitor objectively: Use standardized photography and hair counts, not subjective assessment 5, 4
5. Consider observation instead: For limited alopecia areata of short duration, watchful waiting may be more appropriate than pursuing treatments with marginal evidence 7, 8