Doctor’s Note: Red Light Therapy for Hair Growth

As dermatologists, we see many patients looking for effective treatments for hair loss. Red light therapy has grown in popularity as a non-invasive option for improving hair growth. But does it work? Let’s explore the science, benefits, and limitations of red light therapy to help you make an informed decision.

What Is Red Light Therapy?

Red light therapy, also called low-level laser therapy (LLLT), uses specific wavelengths of light to stimulate hair follicles. Devices such as caps, combs, and panels emit red light at a wavelength usually between 630-670 nanometers. The light penetrates the scalp and interacts with the cells in your hair follicles.

The goal is to improve the health and function of the hair follicles, potentially encouraging thicker, fuller hair over time.

How Does Red Light Therapy Work for Hair Loss?

How Does Red Light Therapy Work for Hair Loss?

Cellular Effects: Red light therapy works by stimulating the mitochondria, often called the "powerhouses" of cells. These structures generate energy (ATP) that helps cells function. By boosting mitochondrial activity, red light therapy improves the overall health of hair follicles.

When hair follicles are healthier, they’re better able to transition from the resting phase (telogen) to the active growth phase (anagen) of the hair cycle.

Improved Blood Flow: Red light may also enhance blood flow to the scalp. Better circulation means hair follicles receive more oxygen and nutrients, which are crucial for growth.

Inflammation Reduction: Hair loss often involves scalp inflammation, which damages hair follicles over time. Red light therapy reduces this inflammation, creating a healthier environment for hair growth.

The Science of Red Light Therapy: What to Consider

When choosing a red light therapy device, it’s important to understand the technical aspects that can impact effectiveness.

LED vs Diode

LED vs Diode

If you’re considering professional treatment, diode-based devices are better:

  • Diode Lasers: These produce a more focused beam of light with minimal scattering. They can penetrate deeper into the scalp, making them more effective for targeting hair follicles. Diode lasers are typically used in professional-grade devices.

  • LEDs (Light-Emitting Diodes): These emit light over a broader area and are commonly found in at-home devices. While they don’t penetrate as deeply as diodes, they are effective for surface-level stimulation and are often sufficient for early-stage hair loss.

Wavelength

Wavelength

The wavelength of light determines how deeply it penetrates the scalp. Red light therapy typically operates in the range of 630 to 670 nanometers (nm):

  • 630-650 nm: This range penetrates the outer layers of the scalp and is effective for improving circulation and stimulating superficial hair follicles.

  • 650-670 nm: These longer wavelengths penetrate deeper into the scalp, targeting hair follicles further beneath the surface.

For hair loss treatment, devices often combine wavelengths in this range to maximize results.

Low Level Laser Light

Diode or LED Count

The number of diodes or LEDs in a device matters because it determines how evenly the light is distributed across the scalp. Look for a device with at least 100 diodes or LEDs for full scalp coverage. Fewer than 100 LEDs may not provide adequate coverage, leading to inconsistent results. 100+ LEDs offer more even and thorough scalp coverage, ensuring all areas receive sufficient stimulation.

Watts Example
Joules Example

Watts vs. Joules: Measuring Power

Understanding power is key to evaluating the effectiveness of a red light therapy device.

  • Watts (W): Measure how quickly energy is emitted, like the intensity of rain—a drizzle or a downpour. Higher wattage delivers more energy per second, enabling faster or deeper penetration.

  • Joules (J): Represent the total energy delivered over time (Watts × time), similar to how much rain falls in total. Even lower-wattage devices can be effective if used long enough to deliver sufficient total energy.

To gauge effectiveness, focus on joules per square centimeter (J/cm²). For hair loss treatment, aim for 4–10 J/cm² per session.

Devices for Red Light Therapy

Several FDA-approved RLT devices are available for home use. These devices come in different forms to suit various needs and budgets:

iRestore Professional Laser Red Light Therapy for Hair Growth System

Helmet Devices

  • Examples: Capillus®, iRestore®, Theradome®.

  • Pros: Hands-free, consistent light distribution, suitable for multitasking.

  • Cons: Higher upfront cost, may feel bulky for some users.

Comb Device Example

Comb Devices

  • Examples: HairMax® LaserComb.

  • Pros: Affordable, portable, and easy to store.

  • Cons: Requires manual operation, covering all areas can be time-consuming.

Sports Device Example

Sports Cap Devices

  • Examples: LaserCap® HD, Kiierr®.

  • Pros: Portable and discreet, ideal for use during daily activities.

  • Cons: May have less even light distribution compared to helmets.

Comparing Popular RLT Devices

The market offers many FDA-approved RLT devices, and they vary in design, features, and effectiveness. Here’s a chart comparing popular options:

Styled Table
Device Shape Laser Diode Quantity Wavelength (nm) Power/Diode Total Power Output Treatment Duration Frequency
Theradome LH 40 EVO Helmet 40 680 5mW 560 mW 20 mins 4x per week
Theradome LH 80 PRO Helmet 80 680 5mW 560 mW 20 mins 2x per week
LaserCap SD Sports Cap 80 650 5mW <400 mW 30 mins Every other day
LaserCap HD Sports Cap 160 650 5mW <1120 mW 30 mins Every other day
LaserCap HD+ Sports Cap 304 650 5mW <1520 mW 30 mins Every other day
iHelmet 200 Helmet 200 650 5mW <1000 mW 30 mins Every other day
Illumiflow 148 Sports Cap 148 650 5mW <740 mW 30 mins Every other day
Illumiflow 272 Sports Cap 272 650 5mW <1360 mW 30 mins Every other day
Grivamax 148 Sports Cap 148 650 5mW <740 mW 30 mins Every other day
Grivamax 272 Sports Cap 272 650 5mW <1360 mW 30 mins Every other day
Revian Red Sports Cap 119 620-660 5mW <595 mW Daily Daily
iRestore Elite Helmet 300 Lasers & 200 LEDs 625 + 655 + 680 <5mW 2500mW Every other day Every other day

How to Use Red Light Therapy

For optimal results, follow these guidelines:

  1. Session Duration: 10–30 minutes per session, depending on the device.

  2. Frequency: Most devices recommend 3–4 sessions per week.

  3. Duration of Use: Noticeable results typically appear after 3–6 months of consistent use.

  4. Maintenance: After achieving desired results, maintenance sessions 1–2 times per week can help preserve hair density.

Consistency is key—skipping sessions can reduce the effectiveness of the treatment.

Calendar

Benefits of Red Light Therapy

  • Non-Invasive: Unlike hair transplants or other surgical procedures, red light therapy doesn’t require needles or incisions.

  • Painless: Most users describe the treatment as relaxing and pain-free.

  • At-Home Convenience: Many red light therapy devices are designed for home use, making it easier to stay consistent.

  • Few Side Effects: The therapy is generally well-tolerated and safe when used as directed.

Limitations of Red Light Therapy

  • Consistency is Key: Results take time and require consistent use, often several times per week for months.

  • Not a Cure-All: While it may help, red light therapy doesn’t work for everyone. It’s most effective for early-stage hair loss.

  • Cost: At-home devices can range from $200 to over $1,000. In-office treatments can also add up over time.

Is Red Light Therapy Effective for Hair Loss?

Studies suggest that red light therapy can be effective for certain types of hair loss, particularly androgenetic alopecia (male and female pattern hair loss). However, results vary, and the therapy works best as part of a broader treatment plan.

In a 2014 clinical trial, participants using red light therapy showed increased hair density compared to those using a placebo device. Another study in 2017 found similar results, with patients reporting thicker, fuller hair after consistent use.

Best Candidates for Red Light Therapy

Red light therapy works best for individuals with early to moderate hair loss. It is less effective for individuals with advanced hair loss where follicles are no longer active or for conditions like scarring alopecia. It’s particularly effective for those with:

Female Pattern Hair Loss

Androgenetic Alopecia

This is the most common type of hair loss, affecting both men and women.

Loss on Crown

Thinning Hair

Patients experiencing diffuse thinning across the scalp can benefit from RLT’s ability to improve hair density.

Female Pattern Hair Loss Social Image

Postpartum Hair Loss

Women dealing with temporary shedding after pregnancy often find relief with RLT.

Red Light Therapy vs. Other Hair Loss Treatments

Minoxidil

Minoxidil is a topical treatment that stimulates hair follicles and improves blood flow. It’s FDA-approved and widely available. While effective, it requires daily application and can cause scalp irritation.

Comparison: Minoxidil is more proven but can be used alongside red light therapy for better results.

Finasteride Pills

Finasteride

Finasteride is an oral medication that blocks DHT, a hormone linked to hair loss. It’s highly effective for androgenetic alopecia but has potential side effects, including reduced libido.

Comparison: Finasteride addresses hormonal causes of hair loss, while red light therapy improves follicle health.

Hair Transplant
Minoxidil Pills

Hair Transplants

Hair transplants involve surgically moving hair follicles from one part of the scalp to another. It’s a permanent solution but expensive and invasive.

Comparison: Red light therapy is less invasive and more affordable, but it won’t replace hair in bald areas.

FAQ

How often to use red light therapy for hair growth?
Red light therapy for hair growth is typically recommended 3-5 times per week for sessions lasting 10-20 minutes. Consistency is key, and results may take 3-6 months to become noticeable.

Is red light therapy good for hair growth?
Yes, red light therapy can be effective for promoting hair growth. It stimulates blood flow to hair follicles, boosts collagen production, and encourages the growth of thicker, healthier hair.