What is Low-level laser therapy (LLLT)?
Low-level laser therapy (LLLT) aka cold laser therapy. It works on the principle of photobiomodulation (PBM), using low-level light energy to stimulate biological process in cells, to promote tissue repair and regeneration.
LLLT is often used in combination with other hair loss therapies such as platelet rich plasma (PRP) injections, stem cells, microneedling, topical serums, oral medications, hair growth supplements, home-use hair growth products, hair transplant surgery etc.
Cold laser therapy also helps to increase the success rate of a hair transplant by making the healing process faster. Therefore, the quality of hair will be healthier, stronger, and better.
How does LLLT work?
LLLT or photobiomodulation treats hair loss and hair thinning by stimulating the hair to enter the growth phase (aka anagen phase of the hair cycle) sooner and prolonging this active growth phase. In addition, LLLT can prevent the hair from entering the resting phase and shedding phase prematurely.
LLLT is a great treatment for hair loss because the light stimulates an increase in ATP (adenosine triphosphate), an important fuel for cells. It also helps to increase blood circulating, allowing more oxygen and nutrients to reach to the hair follicles, and preventing a hormone called DHT (dihydrotestosterone) from stick to the hair roots to cause damage.
Low-Level Laser Therapy (LLLT) VS Red Light Therapy
Some people may use these 2 terms interchangeably, but they are not the same. LLLT is a professional treatment that uses low-level lasers or light-emitting diodes (LEDs) to support cellular processes in the body, it has been researched and backed by scientific evidence to reflect its benefits in treating hair loss and preventing hair thinning. Fun fact, LLLT is also proven to help with joint pain and wound healing.
Red light therapy on the other hand, is a general term to describe the use of red and near-infrared light to improve skin health, reduce inflammation or enhance athletic performance. It can be delivered using LED panels, lasers, lamps etc.
How wavelength, power density, duration and frequency of treatment affect results?
LLLT has been reported to stimulate hair growth in men and women with androgenetic alopecia (AGA). It was approved by the FDA in 2007 to treat hair loss and hair thinning.
Firstly, tissue penetration is maximum at approximately 650–1200 nm. Therefore, red or near-infrared light (600–950 nm) is utilized in LLLT. Tissue culture experiments have shown peak DNA production in 4 wavelength ranges: 614-624nm, 668-684nm, 751-772nm and 813-846nm. Most commonly available LLLT devices utilized a wavelength of 650-680nm, and shown to be effective in stimulating hair growth.
Secondly, the number of LEDs in the device, power density (or how bright the light is), and the distance of the scalp/hair from the light source can affect treatment outcome. Not all devices or lasers are created equal. Professional machines are usually more powerful and more effective than smaller home-use devices.
Finally, the frequency (how many times a week) and duration (how many minutes each treatment) with which light is applied to the head/scalp is another factor. Therefore, a high quality device with the optimal wavelength, greatest power density, and using proper treatment parameters in a professional setting can significantly improve treatment outcome.