Can Red Light Therapy Cause Cancer? The Simple Truth

Can red light therapy cause cancer? Based on over 9,000 studies, red light therapy cannot cause cancer. However, there is a tiny possibility that red light therapy can make existing cancer worse. So far, we’ve only seen this in test tubes and not in humans or animals.

Takeaways:

• I examined 192 studies that included the keywords “low-level light therapy” or “photobiomodulation and “cancer.”
• There was no evidence of red light therapy causing cancer.
• Shining red light therapy on existing tumors did worsen the disease.
• A Petri dish study showed that red light therapy’s ability to promote cell proliferation works on cancerous cells.
• This leaves open the possibility that red light therapy can make an existing cancer worse.
• Right now, this is only a hypothesis and not a fact.

Can Red Light Therapy Cause Cancer?

What’s safer than Tylenol for pain relief? Red light therapy reduces pain, plumps away wrinkles, and shuts down inflammation. But is it safe around cancerous tumors? The answer is “Yes, as far as we know, but there are some things we don’t know.”

What’s Your Worst Quality?

I was once on a job interview for a programming position. Five people interviewed me before the classic question finally came up: “What is your worst quality?” I came prepared for this question and confidentially said, “I work too hard.”

I’d answered the “worst quality” question this way successfully.

“Ha ha ha, I see what you did there,” was the usual response. But not this time.

“You work too hard?” This wasn’t a question, though. It sounded like a question on the outside, but on the inside, it was a demand to offer up a genuine fault, my actual worst quality. My anxiety overcame my ability to answer the question. I was prepared to joke the trick question away. I was not ready to answer the trick question.

My mind went blank. I should have said, “Yes, I could manage my time better, I spend too much time on things that don’t matter,” and that would have answered the question. Instead, I said again, “I work too hard.” Again, the hiring manager replied with a contemptuous and frustrated “You work too hard?”

I was sure we had just done that. We were in a vicious cycle, circling the bowl, as it were. I could have said, “I stay late at night, and then can’t work well in the morning, I don’t manage my time well,” and that would have answered the question. But he was frustrated and my mind was blank, so I said, “Yes, that’s my answer. I work too hard.”

This back-and-forth went on for what felt like an hour and a half. It was probably 2 minutes. Finally, because this stupid conversation was the only issue stopping them from hiring me, the hiring manager let go of his obsession. He offered me the job.

What if Your Answer is Too Good to be True?

Maybe my worst quality is that I don’t know what my worst quality is. So it’s not that I don’t have faults. It’s that I don’t see them as well as I should. Could that be my worst quality?

“Isn’t red light therapy contraindicated on cancerous tumors?” asked a conference goer of pre-eminent Harvard and MIT light researcher Dr. Michael Hamblin.

The first time I listened to Dr. Hamblin ask this question, I was surprised when he said, “I wouldn’t worry about that.” Red light therapy, he said, “is a very effective therapy for cancer treatment side effects such as mucositis,” which are mouth sores from radiation therapy.

My thought upon hearing this answer was that just because red light therapy helps with cancer therapy side effects, that doesn’t make it safe to use around tumors.

The next time I was at a conference, and this same question came up, Dr. Hamblin’s answer had changed.

“You might need to exercise caution right at the tumor area,” he said. “Because the therapy increases cell proliferation, which is something we want to avoid in this case.”

For almost 60 years, red light therapy studies showed that this technique has fantastic benefits with no side effects. That stunning combination of tremendous benefit and virtually no cost is unlike any modality you could name. Even supposedly safe Tylenol kills thousands every year from the liver damage it creates. How can red light therapy be such a success with such little downside?

What’s Right About Light

Light is not a drug, which is tremendously important to understanding the pros and cons of red light therapy. Mammals, including humans, use blue light to regulate our circadian rhythms, telling us when to wake and when to sleep.

We use ultraviolet light to make vitamin D, a hormone in which virtually everyone away from the equator is deficient. The lack of vitamin D correlates with multiple sclerosis, fibromyalgia, and depression.

Unlike a drug, light doesn’t go into a cell to break one process in order to enhance another, thereby creating a workaround to disease and pain. Light energizes the cells, it allows the blood to flow, and these hugely beneficial activities allow the body to heal itself.

It is because light is fundamental to mammalian life that red light therapy has virtually no side effects. I say “virtually,” because there are some contraindications, and because a light overdose can be problematic for some people. Neither of these are technically “side effects,” but we do need to put them into the “worst quality” bucket, and examine what they are.

What is Red Light Therapy’s Worst Quality?

Red light therapy might cause “unwanted cell replication in already cancerous patients.” I am referring to using red light on an existing tumor. If you point a red light therapy device at a cancerous area, you run the risk of increasing cell replication in that area. Because cancer is already a case of unwanted cell replication, the red light ceases to be a therapy and turns into a menace in this case.

192 Answers to “Does Red Light Therapy Worsen Cancer?”

After reviewing the 192 results on pubmed.gov for (PHOTOBIOMODULATION) and (CANCER), the answer is: Red light therapy does not cause cancer. When used improperly at high energy, red light therapy could cause a problem, but that is not it. Red light therapy does not use high energy. Red light therapy inhibits cancer and significantly reduces the side effects of powerful cancer treatments.

Dr. Hamblin reviewed the literature in 2018 (Photobiomodulation and Cancer: What Is the Truth?). He concluded that red light therapy alleviated cancer therapy side effects and has been shown to reduce tumors rather than promote cell proliferation. He pointed out that the symptoms of radiation therapy for cancer listed below are all helped — in a big way — with red light therapy:

• Oral mucositis is the onset of sores and sensitivity in the mouth from radiation therapy.
• Acute radiation dermatitis includes burning and skin cell death. The symptoms emerge within three months after radiation.
• Dysphagia is difficulty swallowing, a common side effect of cancer therapy.
• Osteoradionecrosis is bone death from radiation therapy.
• Peripheral neuropathy is nerve damage causing pain, discomfort, and normal function breakdown of processes such as urination and digestion.

Red light therapy eases the pain of these side effects. Here are just a few of the many studies showing this effect.

• Low-level laser therapy [red light therapy] for oral mucositis in children with cancer
• Long-term safety of photobiomodulation [red light therapy] therapy for oral mucositis in hematopoietic cell transplantation patients: a 15-year retrospective study
• Photobiomodulation [red light therapy] therapy for the prevention of acute radiation dermatitis in head and neck cancer patients (DERMISHEAD trial)
• Evaluation of Efficacy of Low-Level Laser Therapy [red light therapy]
• The effect of photobiomodulation [red light therapy] on chemotherapy-induced peripheral neuropathy: A randomized, sham-controlled clinical trial

Without saying whether red light therapy can encourage tumor cell proliferation, at least in the cases below, the therapy inhibits cell proliferation. And, in fact, red light therapy can inhibit cancer cell proliferation. In one study below, red light therapy effectively treated oral cancer.

• Autophagy upregulation may explain the inhibition of oral carcinoma in situ by photobiomodulation [red light therapy] in vitro
• Photobiomodulation therapy combined with radiotherapy in the treatment of triple-negative breast cancer-bearing mice
• Supportive care of cancer patients with a self-applied photobiomodulation [red light therapy] device: a case series
• Laser Photobiomodulation [red light therapy] (PBM)-A Possible New Frontier for the Treatment of Oral Cancer: A Review of In Vitro and In Vivo Studies

Test Tube Cancers

Some studies found that red light therapy reduced cancer, but at least one study found that cancer got worse in the presence of this red and infrared light.

• Mechanisms of PhotoBioModulation [red light therapy] (PBM) focused on oral mucositis prevention and treatment: a scoping review
• Safety and efficacy of photobiomodulation [red light therapy] therapy in oncology: A systematic review

Another study found that the in vitro (test tube) increase in cancerous cells was not repeatable in humans. The same treatment in the test tube that increased cancer activity decreased cancer activity in vivo or in the person. A high dose of 150 joules correlated with longer survival rates. When irradiance (energy delivery) is too high, the oxidation peaks, causing damage. So higher energy red light therapy is potentially more of an issue than true low-energy therapy.

It’s important to re-emphasize that red light therapy is a “low energy” delivery of light. Very powerful panels might give you faster treatment but could be teetering on a level that is too high to be healthy.

• Laser Therapy [red light therapy] Inhibits Tumor Growth in Mice by Promoting Immune Surveillance and Vessel Normalization
• Irradiance plays a significant role in photobiomodulation [red light therapy] of B16F10 melanoma cells by increasing reactive oxygen species and inhibiting mitochondrial function

We Don’t Know

The big question is: “Does using red light therapy against cancer or cancer therapy side effects cause cancer proliferation? According to the first study below, red light therapy does not induce tumor cell proliferation, but it did in the second study below. However, researchers examining those studies could not determine what was different about the unwanted proliferation parameters. So their advice is, “We don’t know, so be careful.”

• Tumor safety and side effects of photobiomodulation therapy [red light therapy] used for prevention and management of cancer treatment toxicities. A systematic review
• Effects of low level laser therapy [red light therapy] in cancer cells-a systematic review of the literature

What is Red Light Therapy’s Worst Quality?

The incredibly small evidence that red light therapy can make cancer worse is restricted to the test tube and a single outlier case. In contrast, the evidence that red light therapy reduces cancer and treatment side effects is repeatable and confirmable. The worst quality of red light therapy is that it works too hard.

Conclusion

Red light therapy can cause and also prevent cell proliferation. The only evidence for concern is a test tube study in which treatment caused cancer cell proliferation. A corresponding treatment in real humans had the opposite effect. The light reduced cell proliferation in cancer cells.

There is some possibility that red light therapy is dangerous near existing cancers. There is better evidence that it suppresses cancer. At this point, we don’t have the whole picture. So, be careful.

References

https://www.mycancernutritionist.co.uk/anti-cancer-blog/unveiling-the-healing-power-of-red-light-therapy-benefits-mechanisms-and-potential-for-cancer-support
https://www.umassmed.edu/news/news-archives/2014/10/tuning-light-to-kill-deep-cancer-tumors/
https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2022.928484/full
https://pubmed.ncbi.nlm.nih.gov/35847848/
https://pmc.ncbi.nlm.nih.gov/articles/PMC5215870/