Do laser hair removals really cause cancer? Scientifically explained, so you understand once and for all

Laser hair removal has made a big difference in standard of life for many, reducing the need to shave, wax, pluck, tweeze, thread, sugar, the list goes on... The increase in confidence and comfort is truly unparalleled. However, there are whispers that laser hair removal can trigger cell mutations that eventually culminate in cancer. How biologically plausible is this? Has there been research to support this theory? What is the likelihood of this happening to me? As someone who's quite knowledgeable about laser hair removal, I've compiled my (very) long-term research from multiple un-biased sources to answer these questions for you.

In order to answer these questions, we must first understand properly the mechanism behind laser hair removal, as well as how long it's been around. Then I'll break down the science of what happens in your body during a treatment. There will be detailed breakdowns for my science enthusiasts, as well as an explanation in layman's terms for my not-so-science enthusiasts. Then we will compare the scientists' opinion, as well as the opinion of the masses. Finally, if you care to know, I'll share my own opinion, as someone who has many, many friends who get lasers regularly, and has gotten it myself for three years.

What it is 

During a laser hair removal treatment, a concentrated beam of intense light (i.e. a laser) is aimed towards a hair follicle. The melanin (pigment) in the hair absorbs it, and thus the light energy is converted to heat. This heat damages the hair follicle which is responsible for producing that strand of hair. Repeating this procedure over time destroys the hair follicle, which delays hair growth more and more, essentially inhibiting growth in some strands. Typically, laser hair removal sessions are held 6-12 times, and the treatments are spaced 4-6 weeks apart. At the end of treatment, the hair should never come back as it normally did before onset of treatment, at least not at a certified clinic that uses FDA-approved equipment (make sure to inquire about this). After the initial set of treatments, over time, one may notice finer and smaller hairs growing back, or hair growing back a little faster. In this case, a client may return for a touch-up after 6-12 months or longer, to retain the original results. Laser hair removal tends to be most effective on people who have greater contrast between their hair and skin colour, and tends to be more effective for people with darker hair. This is because the pigment of the hair is the target of the laser, not the pigment of the skin. The skin is more likely to be collateral damage if there isn't great contrast. The best candidate for laser hair removal is someone with lighter skin and darker hair, though with advances in laser technology, more options are available for those with darker skin. Laser hair removal is less effective for those with very light hair due to lack of pigment available to absorb the laser. More treatments may be required for those who have dark skin and dark hair, or light skin and light hair.

How long has it been around?

Laser hair removal became commercially available in the early 1990s, meaning it has been commercially available for less than 30 years. However, before it became available in the 1990s, it was performed experimentally and tested for over 30 years. The very first laser designed to destroy hair follicles was invented in 1960. Thus it can be said that laser hair removal has been around for a total of 60+ years at the time of writing this article.

Can laser hair removal cause cancer? 

Spoiler alert: long-term effects of laser hair removal have not been extensively studied, so it cannot be conclusively deduced that these treatments cause cancer, nor can it be conclusively denied. So, let's explore the biological plausibility of this claim and the opinions of experts.

Explaining the science

Importance of wavelength 

Laser therapy does not use the same wavelengths of light that are characteristic of ultraviolet rays  found in UVA (315-400 nm) and UVB (280-315 nm). Light at these wavelengths, which you know as UVA and UVB sunlight, are known to damage DNA in cells and contribute to cancer.  Wavelength, measured here in nanometres, or nm, determines the energy per photon, and is inversely proportional to energy. This means the shorter the wavelength, the greater the energy per photon. The intensity is the total energy per time arriving in a unit area.

The lasers used in laser hair removal can be grouped into different categories according to their wavelengths. One category consists of ~694 nm infrared lasers. Other commonly used lasers are 755 nm lasers, 800 nm semiconductor diode lasers, and, my favourite, the 1064 nm YAG lasers.

"Intensity" refers to the total energy per time arriving in a unit area. Energy in this case is the energy of the laser, and the unit area refers to surface area of your skin. Why is this important? As you can see above, wavelengths of lasers used in laser hair removal are much larger than wavelengths of harmful cancer-causing sun rays. A greater wavelength (greater nm) used on the skin means less energy is distributed over your skin. This is why the lasers in laser hair removal are not generally regarded as harmful or carcinogenic, unlike the sun's UVA/UVB rays that are known to be carcinogenic. 

Ionizing vs. non-ionizing radiation

Now that we've analyzed the importance of wavelengths, let's take a look at ionizing vs. non-ionizing radiation. There are two types of radiation - ionizing and non-ionizing. Ionizing radiation is much, much higher in energy and thus is able to detach electrons from an atom, thereby "ionizing" the atom. Ionizing radiation is used to kill cancer cells - you know it as radiotherapy. Laser hair removals make use of non-ionizing radiation, which are not intended to alter the morphology of, and thus kill, a cell. Ionizing radiation is characterized by higher frequency and shorter wavelength, both properties of cancer-causing rays. In contrast, non-ionizing radiation used in laser hair removals can only produce non-mutagenic effects - the risk of cancer is very insignificant. 

X-rays and gamma rays are more dangerous in terms of cancer risk as they are known as high-frequency ionizing radiation. Medical imaging tests such as CT scans, and, duh, x-rays, make use of this type of radiation. Ionizing radiation passes through the body and therefore causes direct damage to a cell's DNA even if it does not kill it, which can increase the likelihood of cell mutations down the line, which can lead to cancer. The Food and Drug Administration only allows non-ionizing radiation to be used in laser hair removal procedures.

Opinions of scientists and doctors

Dermatologists claim that light energy from the non-ionizing radiation that is used in laser hair removals stays at the surface of the skin. These lasers are either very unlikely to, or simply unable to, penetrate the skin or cause enough disturbance that they alter the atomical makeup of a cell. Thus, these lasers don't cause DNA damage. By this logic, CT scans and x-ray tests that make use of ionizing radiation are actually more likely to be harmful to humans compared to laser hair removals.  It is an undeniably accepted fact within the scientific community that CT scans and x-ray tests can cause cancer due to the fact that they use ionizing radiation. Remember, laser hair removals use NON-ionizing radiation, which does not carry proven risk of cancer.

This 2016 study  by Kurt A., Ashack BA, and Jerry D. Brewer (MD) focuses on patients who have benign nevi (moles or other growths on skin), and attempts to deduce if laser hair removals could result in these moles undergoing malignant transformation (becoming cancerous). They study concluded that laser hair removals should be applied with caution in patients with risk factors for melanoma, but the evidence supporting or negating laser therapy as cancerous is inadequate.  Some other researchers have observed abnormalities in dysplastic nevi (moles) after laser hair removals, and have thus suggested exercising caution for those with a family history of skin cancer until further research concludes whether the changes in these moles can become malignant.

During laser hair removal sessions, sometimes a plume or gas is emitted in the air after burning of hair. This is not common, but it is noticeable when it happens and one can often smell it in the form of something burning. Chronic exposure to particulate matter such as this has been linked to negative respiratory health effects including lung cancer, and this 2017 study by Eshleman Emily J, LeBlanc Mallory, Rokoff Lisa B, Xu Yinyin, and Hu Rui et al. observes the effects of exposure to these ultrafine particle concentrations during laser hair removals. The study concluded that these procedures generate exposure to ultrafine particles for individuals performing the procedures and thus the practitioners themselves should wear protective equipment and utilize smoke evacuators. The study does not seem to observe patients as being in risk - possibly due to the very low exposure levels that a patient experiences. This 2017 article by Caerwyn Ash, Godfrey Town, Rebecca Whittall, Louise Tooze, and Jaymie Phillips, examines relevant literature and a number of studies, and is an excellent source. It concludes that repeated exposures to laser hair removal (52 treatments over 6 months) did not result in increased cancer risk or tumour formation for subjects. According to this study, the existing evidence of laser hair removal treatments has not yet raised concerns regarding long-term safety as very few cases of melanoma post-treatment were observed, and these cases could not be linked to the laser hair removals. A dermal burn as a result of laser hair removal does not increase the long-term likelihood of tumour formation, according to the study. The study additionally concludes, upon examining other literature, that if a dermal melanoma is treated with laser hair removal using IPL lasers accidentally, there shall be no photochemical reaction as typical IPL wavelengths are not capable of altering the melanoma to harmful biological extents (for clarification, read my analysis of wavelengths above).

If you want to read more about these scientists' opinions, I will include details of their works below*.

Are there other risks I should be aware of? 

Because it's a laser that is designed to kill a hair follicle, it does carry the rare risk of burns, blisters, and scars. You may notice your skin is a little more sensitive, or a bit itchy, a day after your appointment, but this will most likely happen for your first one or two appointments, and is very manageable. Slight redness may occur, especially for lighter skin tones. Slight swelling may occur. These side effects should be less severe than any you experience while waxing and shaving. Your dermatologist or technician should be trained to apply topical anesthetics to decrease the chance of any side effects, and should inform you of products you can use that you have at home (such as Vaseline) that can alleviate symptoms. Pigmentation is very rare, but can happen, especially to those with darker skin tones. This should be temporary. If pigmentation persists, inform your technician - a good, medical grade clinic should carry hydroquinone products to lighten any dark spots caused by laser. Treatments should not hurt, and should feel like a slight pinch. Several intensity levels are available and your technician should work with you to find the correct intensity for you.

Some women are concerned about treating areas near the reproductive organs, and according to the breakdown I provided above, there should be no additional risk in treating these areas in terms of influencing reproductive health. Additionally, experts claim there is no risk as the laser does not penetrate beyond the depths of the hair follicle - there is no way the laser would reach the internal organs. The "experts" I'm referring to here include three doctors: a regular physician, a dermatologist, and gynecologic oncologist, as well as additional online medical newsletters that also agree with this opinion.

The takeaway

Companies offering laser hair removal claim that laser hair removals most definitely will not cause cancer. According to the available scientific literature, opinions of most scientists, as well as existing evidence in the form of millions of patients, it seems that laser hair removals most likely do not cause cancer. I was also able to find lots of medical newsletters seemingly unaffiliated with laser hair removal companies that also claim that laser hair removal doesn't cause cancer. However, science is always advancing and/or changing. Time seems to be our ally in this case, as laser hair removal has been around for a long time and has not been definitively linked to cancer, even with today's advanced technology.

So should you get laser hair removal? 

I'll sum up the most up-to-date research to make it easier for you.

Clients' opinion: most have experienced a dramatic difference in hair growth, would recommend laser hair removal, and very few have had a bad experience. No cases of post-treatment melanoma have been linked to laser hair removal. No cases of other cancers have been linked to laser hair removal.

Scientists' opinion: likelihood that laser hair removal causes cancer is very low. I explained why in my scientific breakdown - the high wavelengths used in laser hair removal light is uncharacteristic of carcinogenic light, and non-ionizing radiation is used, which has not been proven to cause cancer as ionizing radiation has. We can't prove that it's carcinogenic in the long-term, but we also can't guarantee that it's not carcinogenic in the long-term.

My opinion: right now seems like a good time to get laser hair removals as they've been around for pretty long - long enough to feel at peace that laser hair removals shouldn't cause cancer. If such a drastic thing were true, with the advanced technology we have now, it should have come out already, especially considering how many people get it - the sample size is huge. As a biomedical engineering student who's been very interested in the sciences all my life, as well as someone who's gotten laser hair removals in the past three years, as well as someone who has countless friends who've done so as well, I would recommend it. However - please make sure you attend a medical grade clinic with many good reviews. I recommend New Derma Med if you live in Toronto - their team consists of certified surgeons, dermatologists, and nurses who have been doing this for a long time and use the best technology available right now. Toronto Laser Clinic is also a trustworthy, more affordable option.

To be honest, severe side effects as a result of laser hair removals are very rare. I have rarely noticed even the smallest side effects, nor have any of my countless friends who have gotten laser hair removals. To reduce chances of side effects, please make sure to attend a medical grade clinic that's been around for a long time, and follow instructions, such as restrictions around tanning or sun exposure 24 hours prior to, and after, a treatment. It is best to keep updated with recent research, practice good hygiene, and follow your laser hair removal technician's instructions to prevent side effects. Exercise other practices to decrease chances of developing cancer as usual, such as proper sun protection.


Sincerely,

Annesa

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*You may not have access to the links I provided, as some of these scientific journals require payment or a university membership. Thus, here are details of articles I mentioned - you may wish to access them by other means. Please do read - they are excellent sources!


Ashack, K.A. and Brewer, J.D. (2017), Clinically atypical nevi following diode laser therapy. Int J Dermatol, 56: 579-580. doi:10.1111/ijd.13376

Ash, C., Town, G., Whittall, R. et al. Lasers and intense pulsed light (IPL) association with cancerous lesions. Lasers Med Sci 32, 1927–1933 (2017). https://doi-org.ezproxy.lib.ryerson.ca/10.1007/s10103-017-2310-y

Eshleman, E. J., LeBlanc, M., Rokoff, L. B., Xu, Y., Hu, R., Lee, K., . . . Hart, J. E. (2017). Occupational exposures and determinants of ultrafine particle concentrations during laser hair removal procedures. Environmental Health, 16 doi:http://dx.doi.org.ezproxy.lib.ryerson.ca/10.1186/s12940-017-0239-z