Laser Hair Therapy Couldn’t Possibly Hurt You — Or Could It?




The application of low-level laser therapy (LLLT), or laser hair therapy, to address hair loss was first discovered by accident — with laboratory mice. Researchers were testing laser on wounds, where the hair around the wound was shaved. What they noticed in the mice receiving LLLT versus those who weren’t (the control group) was their hair grew back faster.

Since then, and for more than 30 years, researchers and hair restoration therapists have been using the technique on humans. Popular for decades throughout Europe, laser hair therapy received approval as safe by the U.S. Food and Drug Administration in 2007. This approval is all about safety — the FDA does not confirm or deny efficacy.

How laser hair therapy safely restores hair growth

To appreciate how LLLT is safe, it helps to understand how it works.

LLLT approaches the treatment of thinning hair from a noninvasive standpoint. Equipment varies somewhat, but between 110 and 116 laser diodes are directed at the scalp, typically applied in a head cap (it can also be administered with a handheld comb). The light is in the 630- to 670-nanometer range, which is where the color red occurs on the light spectrum. The power of the light is at low wattage, which allows it to remain cool throughout the procedure.

The exposure of the scalp to these tiny beams of light is called photobiology, which causes reactions on both physical and chemical levels. Hair follicles, in particular the very tiny hairs on follicles where loss is progressing, absorb this light. The reaction happens on an intracellular level, where cytochrome c, an enzyme, sends photochemical signals throughout the hair follicle. The result is a decrease in apoptosis or programmed cell death.


The actual efficacy (“does it work?”) of laser hair therapy is subject to variations among individuals. Those variations are:

  • What type of hair loss is occurring? Primarily male and female patients with androgenetic (also called androgenic) alopecia can benefit from LLLT. That means it can benefit male pattern baldness and female pattern baldness, but other causes such as alopecia universalis or trichotillomania will not be affected by it. Some claim it can be used for alopecia areata and with individuals undergoing chemotherapy.
  • Is the hair loss recent or long-standing? Laser hair therapy is probably most effective where hair is actively receding, not on hair lost a long time ago. There needs to be some life left in those follicles for it to receive the laser, translate it on an intracellular level and stimulate growth.
  • Did the patient get regular treatment? Twice-weekly exposures to the light, continued for a full year, seems to be essential to achieve results. Almost all LLLT proponents discourage sporadic use of the technique.

All that said, there are no peer-reviewed scholarly journals reporting double-blind studies that scientifically prove effectiveness. Most results are self-reported. Painstaking measurements in higher-priced studios where laser hair therapy is administered show an increase in hair shafts and overall thickness of those shafts in those areas where hair growth has not fully ceased.

Note that LLLT is often used in combination with minoxidil (Rogaine and other brands), finasteride (Propecia) and hair transplant surgery, reportedly with good results in all such cases.

On your own with handheld laser hair therapy combs

Self-administered laser hair therapy with handheld combs is available. These devices are typically sold at lower power (wattage). While that may be perceived as a safety advantage, it cannot overcome the “more is more” mentality. If someone chooses to overuse his or her comb — spending hours every day, perhaps in a desperate attempt to regrow hair quickly — the worst outcome is ineffectiveness. The body’s reaction to the light can diminish with excessive and constant use. There are no reported cases of this actually happening. Because these are cool lasers, there is no concern about overexposure causing burns.