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LLLT therapy for hair loss only effective in paid studies

The use of low-level laser therapy (LLLT) to treat hair loss has been gaining popularity in recent years. According to the manufacturer, LLLT treatment would stop the progression of hair loss and promote hair growth, resulting in thicker, stronger hair shafts and regrowing hair. As evidence for the claims, the manufacturer refers to some studies from 2009, 2013 and 2014. [1] [2] [3] Studies that showed that the LLLT device tested did indeed provide more and thicker hair. And we have to admit, if the studies are to be believed, LLLT seems to be a very promising technique. For example, it is not only used to treat hair loss, but it is also used to treat wrinkles, acne, scars and heal burns.[4]

Key points

  • research results promising, but claims exaggerated.
  • increase in hair growth and hair thickness, but says nothing about stopping hair loss.
  • some studies financially sponsored by the manufacturer
  • no long-term studies. Results are relevant, as we have seen with minoxidil that appearances can be deceptive. Minoxidil, like LLLT, provides an increase in hair thickness and hair density. At least for the first two years. After that, its efficacy decreases and hair loss resumes.

    • What is Low-level Laser Therapy?

    Low-level laser therapy (LLLT) is a treatment method that uses light. Red and infrared light to be precise; with a wavelength of 600 to 950 nanometers (0.0006 to 0.00095 mm).[5] How this works exactly is not relevant for now, but let us say that light, depending on its wavelength, has positive or negative effects.

    Ultraviolet light, for example, is part of the radiation emitted by the sun and has a wavelength of 100 to 400 nm. It is essential for the production of Vitamin D and makes us tan, but it also has adverse effects. It damages your DNA, causes skin ageing and contributes to the development of skin cancer.[6]

    The light that LLLT uses therefore has a wavelength of 600 to 950 nm. This is partly visible light (380 to 700 nm) and partly infrared light (700 to 1,000,000 nm). It is this particular part, that of 600 to 950 nm, which studies have shown to have positive effects on hair. Using LLLT below or above this wavelength has no effect on the hair.[7]

    LLLT for hair loss

    One of the effects attributed to the use of LLLT is that it would stop hair loss. A claim we hear more often, but rarely fulfilled. Products such as caffeine shampoo and saw palmetto promise the same, but turn out to be useless in practice. Those claims are nothing more than a false promise. And this also seems to be the case with LLLT.

    In order to stop hair loss, you need to reduce the amount of DHT. A hormone that causes hair loss by damaging the hair follicles. Reducing this hormone has the effect of stopping hair loss. Finasteride is a good example of this. One 1 mg tablet reduces the amount of DHT by 70%, stopping hair loss in more than 80% of men.[8]

    LLLT on the other hand has no effect on DHT. This makes it very unlikely that LLLT can stop hair loss. A scientific review from 2012 seems to confirm this and concluded that, due to a lack of evidence, they see no reason to recommend LLLT for the treatment of hair loss.[9]

    Moreover, the studies that examined the relationship of LLLT and hair loss lasted a maximum of 6 months. This is too short to be able to say anything about the stopping of hair loss. A minimum of 12 months is required for this.

    LLLT for stimulating hair growth

    The second claim made on LLLT is that it would promote hair growth and thicken hair. This is shown in the study published in the scientific journal Skin Appendage Disorder.[10] This study compared the effectiveness of the RAMACAP (LLLT device) with that of a fake device. They saw an increase of 10.21 cm² hairs in the laser group compared to an increase of 3.95 cm² hairs in the group treated with the fake device over a 6-month period. Another study published in Lasers in Surgery and Medicine compared the effectiveness of the iGROW laser with Minoxidil 5% They saw an increase of 49.60 cm² and 50.8 cm² hairs for Minoxidil and LLLT respectively after 4 months of treatment.

    Other studies also saw an increase in hair density after treatment with LLLT.[11] The effect of LLLT is possibly due to the dilation of the blood vessels, known by the medical term vasolidation. A property shared with Minoxidil. Possibly both agents work on the same principle.

    Criticism of the studies

    Despite the fact that the studies are unanimous on the effects of LLLT for the treatment of hair loss, there are a number of issues that we would like to draw attention to. Some criticisms that indicate "why" LLLT might be a lot less effective than the study results suggest.

    Study sponsorship

    Almost all studies that consider LLLT to be an effective treatment method against hair loss are financially sponsored by the company that sells the device.[12] [13] [14] Usually the research results from such studies are less reliable. The companies benefit from results that show that the device is effective. The same happend with studies on the efficacy of caffeine shampoo and saw palmetto for treating hair loss.[15][16][17]

    Our analysis showed that negative study results were omitted by purpose and that their researchers published questionable studies on different products from exactly the same company.[18] [19] This is not to say, by the way, that all sponsored studies are unreliable, but rather that you can take such study results with more often a grain of salt.

    Study length

    Clinical trials of LLLT take place over a short period of time, usually 6 months. Critically, there is no follow-up after treatment. It is unknown whether the improvement seen in LLLT in these studies is long-lasting. This is relevant as we have seen that Minoxidil improves hair density during the first 12 months, but its effectiveness declines thereafter.[20]

    Short-term studies at the time claimed that Minoxidil could stop hair loss. However, long-term studies showed that this effect was temporary and that hair loss resumed after a period of 12 months, despite the use of Minoxidil.

    Clinical improvement

    The digital analayses performed with the Trichoscan can be an easy method to evaluate hair growth, but is prone to errors. The Trichoscan showed promising results in terms of an increase in hair density, but were hardly clinically relevant. In most studies the increase in hair density was measured on the basis of an increase in 1cm².

    The results thus say nothing about an increase in the total amount of hair.

    Final word

    We see no reason to assume that Low Level Laser Therapy is an effective treatment method for hair loss. It is highly unlikely that LLLT will stop hair loss, partly because of its lack of influence on DHT.

    The positive results on an increase in hair density seem promising, but are difficult to interpret because the majority of these studies were financially supported by the manufacturer of the device being studied. Such study results generally appear to be less reliable.

    Furthermore, only one study evaluated the effects of LLLT during a follow-up. The study showed that the effects of LLLT are temporary and that one needs to undergo periodic treatment to maintain the results. How many treatments are needed and in what time frame has not been investigated. Future research should reveal this.

    Conclusion: LLLT is not effective in stopping hair loss. Studies do seem to show a (temporary) increase in hair growth. However, due to financial sponsorship by the manufacturer, the current results are questionable. Independent research is needed to confirm the findings.