What Is Low-Level Light Therapy and How Is it Used for Alopecia?
Alopecia is a common disorder leading to hair thinning and hair loss. It affects many men and women worldwide and can be an emotionally devastating and anxiety provoking condition. There are different forms of alopecia with different causes (See Table 1).
Table 1. Types of Alopecia
Type of Alopecia
Who it Affects
(also known as male pattern baldness or female pattern baldness)
Androgenetic alopecia is the mot common type of alopecia, affecting up to 50% of men by age 50 and up to 32% of women over age 20
Many causes – genetic susceptibility, excess male sex hormones (DHT), low estrogen, insulin resistance
Can affect anyone
Stress-induced hair loss – excess hair shedding following stressful events, trauma, severe illness, malnutrition, etc.
Affects up to 2% of Americans by age 50, with men and women equally affected
Autoimmune inflammatory disease, many have family history of alopecia areata
Can affect anyone
Lupus erythematosus, lichen planopilaris, central centrifugal cicatricial alopecia
Medication Induced Hair Loss
Women taking oral contraceptive pills, people taking chemotherapy medications, anti-thyroid medications, etc.
Medications such as chemotherapy drugs can destroy the rapidly dividing hair follicular cells, leading to hair loss
A first line treatment for many people with androgenetic alopecia includes the topical medications, minoxidil and finasteride. These medications may not work for everyone. In order to be effective, they must be used indefinitely and can be burdensome by the need to use them daily. Another option is surgical hair transplantation, which is limited by many factors including cost and individual hair distribution and donor hair supply.
An emerging treatment option for alopecia is Low-Level Light Therapy. The United States Food and Drug Administration (FDA) cleared Low-Level Light Therapy devices for marketing an effective and safe option for male and female androgenetic alopecia. Low-Level Light Therapy can be done as an in-office treatment, or people can purchase commercially available devices for use at home.
Low-Level Light Therapy Devices for Alopecia
HairMax® LaserComb and LaserBand – FDA approved to promote hair growth in men and women with androgenetic alopecia.
iRestore™ Hair Growth System – this at home device was cleared for marketing by the FDA to treat hair loss in men and women.
iGrow Hair Growth System® - at home helmet device cleared for marketing by the FDA to promote hair growth in men and women with androgenetic alopecia.
Super Lizer – Japanese device shown to improve hair growth in patients with alopecia areata.
How Does Low-Level Light Therapy for Alopecia Work?
There are several proposed mechanisms for how Low-Level Light Therapy works for alopecia although the exact mechanism is not yet known. Most devices and studies have used wavelengths of red light ranging from 635 to 900 nm.
Proposed Mechanisms for Low-Level Light Therapy
One mechanism suggests that Low-Level Light Therapy targets a tiny organelle within our cells called the This might lead to an alteration in cellular metabolism, increased ATP production (an energy molecule), and production of messenger molecules called transcription factors that increase hair growth promoting proteins.
Low-Level Light Therapy may increase production of nitric oxide (NO), leading to greater blood flow to hair follicles.
Low-Level Light Therapy may alter production of dihydrotestosterone (DHT), which is a hormone implicated in the cause of androgenetic alopecia.
Low-Level Light Therapy may modulate the immune system and inflammatory responses that are important in normal hair growth.
What Condition Does Low-Level Light Therapy Treat?
FDA-cleared uses for Low-Level Light Therapy: Most Low-Level Light Therapy devices available on the market are approved to promote hair growth in men and women with androgenetic alopecia.
How Is Low-Level Light Therapy Done?
Low-Level Light Therapy for alopecia is available as at-home devices, in the salon setting, or as treatments in a health practitioner’s office. Low-Level Light Therapy devices deliver red light (650-900 nm wavelength light) at 5 mW. Most clinical studies demonstrated the best results when people used the Low-Level Light Therapy device daily or every other day for approximately 10-20 minutes per treatment for four to six months.
Some devices operate by a comb with lights that the person can move across their scalp for the instructed amount of time. Other devices consist of a helmet that covers the entire scalp for the duration of the treatment. Despite promising clinical results, there is still limited evidence on whether at-home Low-Level Light Therapy devices are as effective for alopecia as receiving treatment in a licensed practitioner’s office.[6,10]
What Are the Common Side Effects and Risks of Low-Level Light Therapy?
Low-Level Light Therapy is generally well tolerated with low incidence of adverse events. Side effects may include headaches, skin pain or burning, itching, scalp redness, and mild tingling.
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