Low-Level Laser Light Therapy

Hats and brushes that can help hair grow 

It is usually recommended to be on at least two different modalities of treatment for hair maintenance and regrowth and we’ve already discussed some in previous issues (finasteride, minoxidil, and microneedling).

Another non-surgical hair restoration modality you might be interested in is low-level laser light therapy.

Photobiostimulation therapy (PBM therapy), also known as Low-Level Laser Therapy (LLLT), has been shown to aid in nerve regeneration, joint pain relief, stroke recovery, prevention and treatment of mucositis, and, importantly for us, hair growth. 

How does LLLT help hair grow? 

Low-level laser light, which is in the red or near-infrared light range (600 to 950 nanometers), is the portion of the electromagnetic spectrum that has visible light.

This range of light helps hair grow by stimulating the stem cells in the hair follicle bulge and, consequently, shifts the follicles towards an anagen (growth) phase.

What makes the treatment safe, apart from using lower wavelengths, is using lower power. We have to be careful when using the therapy because low radiation, although it invokes biostimulation at appropriate power levels, can cause inhibition at higher radiation doses. We are aiming for a power level that is sufficient in creating a positive change while not hindering hair growth.

How does LLLT compare to other therapies?

A study compared the results of other studies that reported on how much hair density improved with the use of different modalities including finasteride, minoxidil, and laser therapy. To clarify, hair density is defined as hairs per centimeter squared.

What the study found is that, overall, hair density improvement is about 13-27 hairs per cm² for oral finasteride and, for topical minoxidil, about 12-20 hairs per cm². When it comes to low-level light therapy, the improvement is 17-20 hairs per cm² in some of the bigger studies done on the modality.

What kind of LLLT devices are available?

There’s a wide range of devices that use lasers or LEDs. For example, there are combs, hands-free sports caps, and headbands.

Apart from style the devices differ in features as well and choosing the device that best suits you is going to depend on different factors. These include price, wavelength, power settings, and the frequency and duration of application you are comfortable with. We will discuss them all further below.

Keep these differences in mind when selecting and, just like with any other medical device, it is always best to do your research and consult with a doctor.

Lasers vs LEDs

One of the characteristics of LLLT devices that can have a major influence on their price is whether they use lasers or LEDs.
Lasers produce a coherent narrow band of light and are more expensive than LEDs. LEDs are cheaper, but the spectrums of light they generate are more incoherent and divergent. Potentially, LEDs can produce the necessary energy levels for hair restoration therapy, and so, an increasing number of manufacturers are utilizing LEDs to lower costs.


Most LLLT devices on the market use a wavelength of 655 nanometers, as that is what was originally tested in clinical trials and has persisted as the most commonly used laser wavelength.
There are some more recent studies suggesting a possibly better efficacy at a slightly higher range. Because of this, 700-800 nanometer range LEDs are being incorporated into low-level laser light devices They can deliver the same recommended energy level, which is about four joules per centimeter squared, but they do use a different light source. 

Power settings

Higher energies, meaning a higher dose of irradiation, increase hair density more than lower energies. As we mentioned before, this is true up to a certain point after which the irradiation can harm hair growth.
It's important to keep in mind that we don’t know where this point is and that a lot of studies don't report on the total dose of irradiation used. Calculating the total energy output of a device is difficult and many of the companies that appear in studies don't release this information. Many don't even calculate it.

An important note

Darker skin decreases the transmission of light and can reduce the efficacy of low-level laser light treatment. Laser devices for hair regrowth are cleared for individuals with a Fitzpatrick skin type of I-IV and the clinical trials have overall been done on those with these Fitzpatrick skin types.

What are the possible side effects?

In terms of the risks, if it's done at the right energy level, low-level laser light therapy is overall very safe. However, like anything that has any degree of efficacy, there are always going to be some risks to it. These include:
  • Temporary shedding can occur in the first few months. It tends to disappear as you continue to apply the treatment.
  • There's a risk of stimulating some dysplastic or malignant lesions on the scalp. In theory, you can cause them to grow more if you apply low-level light therapy.
  • Other side effects that have been reported are acne, burning sensations, dry skin, headaches, and itchiness.










The content of this newsletter is for entertainment and educational purposes only. This content is not meant to provide any medical advice or treat any medical conditions. Patients must be evaluated by an appropriate healthcare provider on an individual basis and treatment must be tailored to meet that patient’s needs. Results and particular outcomes are not guaranteed.

Written by Aleksandra Božović | Edited by Dr. Gary Linkov
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