Red Light Therapy & Cancer

What is Red Light Therapy?

In the world of holistic health, a fascinating therapy has been gaining a lot of attention among the health conscious: red light therapy (RLT), RLT is also known as photobiomodulation (PBM) or low-level light therapy (LLLT) in scientific and clinical research.

Perhaps you’ve heard of it and are wondering…

• Can red light therapy cause cancer?

• Is red light therapy safe for cancer patients?

• Can red light therapy be of any benefit for cancer patients?

• Can red light therapy help with cancer treatment side effects?

• Are there any risks associated with red light therapy for cancer patients?

In this article, we’ll explore these key questions and dive into the science behind red light therapy, and its potential support for cancer patients, how it affects mitochondria, as well as things to consider for using red light therapy safely at home.

How Red Light Therapy Works

Red light therapy relies on the unique properties of light wavelengths in the red (620-700nm) and near-infrared (700-1100nm) ranges, which can penetrate the skin and reach the mitochondria – the energy producers within our cells.

When these wavelengths interact with mitochondria, it triggers a cascade of responses that improve cellular function and energy production, supporting various health benefits.

Before we delve into more detail it’s important to clarify how Red Light Therapy differs from Photodynamic Therapy in a medical context.

What’s the difference between Photodynamic therapy (PDT) and Red Light Therapy (RLT)?

Photodynamic therapy (PDT) is a medical treatment used for certain skin conditions and some cancers. It involves applying or giving a photosensitising drug that collects more in abnormal cells. A specific light is then used to activate the drug, creating a reaction that damages those targeted cells. PDT is carried out under clinical supervision and has a clear therapeutic intent.

Red light therapy (also called photobiomodulation (PBM) in research) is different. It uses red and near-infrared light without a photosensitising drug, and the goal is typically to influence cellular signalling involved in repair and inflammation.

In cancer care, this is most often discussed in the context of supportive care (for example, skin reactions, pain, wound healing, or oral mucositis), not as a cancer treatment itself.

Because both involve “light”, they’re sometimes confused — but they’re not the same intervention.

Mitochondria, Cancer, and Red Light Therapy

Researchers believe a key target of PBM is the mitochondria — the “energy centres” inside our cells. When mitochondria absorb this light, it can influence how cells make energy (ATP) and how they send signals involved in repair and inflammation (including molecules such as reactive oxygen species (ROS) and nitric oxide (NO)).

When you bring cancer into the picture, this becomes more nuanced. The same cell-signalling pathways involved in healing are also involved in cell growth and immune activity, so PBM’s effects can vary depending on the tissue, the person, and — importantly — the dose used.

Can Red Light Therapy Cause Cancer?

Given that red light therapy can support healing and cell repair, some clinicians have been cautious about using it in people with cancer — largely out of concern it might also encourage the growth of existing tumours. One paper (Myakishev-Rempel, 2012) looked at a very practical safety question:

If red light therapy can encourage cell repair and growth in wound healing, could it cause cancer cell growth?

To explore this, the researchers used a well-established mouse model where mice develop multiple non-melanoma skin cancers after UV exposure.

Once visible tumours were present, one group of mice received 670 nm red LED light to the whole body twice daily (a total of 5 J/cm² per day) for just over five weeks, while a control group was handled the same way but without the light.

The team then measured hundreds of individual tumours day-by-day using standardised photographs. The key finding was reassuring within this specific set-up: the red light treatment did not measurably increase tumour growth compared with the control group over the study period.

The authors concluded that, at these settings, red light therapy may not need to be automatically ruled out purely because cancer is present, while also emphasising that more research is needed before applying this confidently to humans or to other cancer types.

Can Red Light Therapy cause Melanoma growth?

If you’ve had melanoma (or you’re worried about it), it’s natural to wonder whether red light therapy could be risky — especially because red light can influence how cells function and repair.

One research study (Austin, 2022) looked at this question using melanoma cells in the lab and mice with melanoma. This is important: it was not a study in people. They used a red LED device and tested different “doses” of red light:

• In the lab, melanoma cells were exposed to red light for 2–4 hours to reach the doses used in the experiments.

• In mice, red light was used daily for 4, 6, or 8 hours depending on the dose.

That’s much longer than most people use at home, which matters when we interpret the results. What they found:

• In lab studies, red light slowed melanoma cell growth; When melanoma cells were treated with red light, the researchers saw fewer melanoma cells afterwards.

• At the lower tested dose, the main effect seemed to be slower growth (the cells weren’t dividing as quickly).

• At the higher dose, there was evidence of more programmed cell death (a controlled way cells can break down).

• In mice, the highest dose slowed tumour growth. The highest dose tested led to tumours that were significantly smaller than those in the control group.

• The study also found changes in the skin around the tumour; The researchers looked at immune markers and found that the skin around the tumours showed increased staining for a type of immune cell marker called CD103 at the highest dose. They discuss this as potentially relevant because CD103 is linked in other research to more favourable immune activity in melanoma.

• Short-term safety in mice looked reassuring in this set-up. In mice without tumours, daily red light exposure at the doses used did not cause visible skin redness or inflammation, and their body temperature was monitored during treatment.

Can Red Light Therapy Cause Cancer Cells to Grow?

This study is an interesting early signal that, under specific experimental conditions, red LED light did not stimulate melanoma growth in these models and may even have reduced it — especially at very high doses.

It’s important to note that because PBM effects can be dose-dependent (sometimes ‘biphasic’), findings at very high exposure times may not translate to typical home protocols. This study doesn’t prove that red light therapy treats melanoma in humans, or that the same results apply to at-home devices.

If you have current melanoma/skin cancer (or you’re under investigation), don’t use PBM over the lesion area unless your dermatologist/oncology team explicitly okays it.

Is Red Light Therapy Safe for Cancer Patients?

One review (Paglioni, 2019) pooled 27 human clinical studies where photobiomodulation (PBM) was used for cancer treatment toxicity it concluded from the current literature that:

Photobiomodulation (red light therapy) did not find evidence of tumour-safety concerns in the clinical studies reviewed when PBM was used to manage treatment toxicities.

While research on red light therapy’s role in cancer is still limited, and more prospective studies with long-term follow-up are needed; there are certainly some studies suggesting it may provide benefits for cancer patients in specific ways:

• Supporting skin reactions from radiotherapy

• Helping with Oral Mucositis, dry mouth, mouth ulcers

• May help reduce symptoms of Chemotherapy-Induced Peripheral Neuropathy

• Support Breast cancer-related lymphoedema

The potential benefits of red light therapy for cancer patients

Can Red Light Therapy Help with Dermatitis from Radiotherapy?

Radiation dermatitis (the sore, red, peeling or ulcerated skin) can happen during radiotherapy in people being treated for head and neck cancers. One clinical study (Zhang, 2018) looked at whether red light phototherapy could help with dermatitis.

Sixty patients were randomly split into two groups: everyone received routine skin care, and one group also received red light treatment for 10 minutes, twice daily, throughout radiotherapy.

Overall, in the red light group, dermatitis grades were generally milder and pain scores were lower during weeks 2–4. The authors concluded that red light therapy may help reduce discomfort and support skin healing so radiotherapy can continue more smoothly.

Can Red Light Therapy Help with Oral Mucositis During Cancer Treatment?

Oral mucositis refers to painful inflammation and ulceration in the mouth, which can occur during chemotherapy and radiotherapy (especially in head and neck cancer). A major reason red light therapy (photobiomodulation) has gained interest in oncology is its potential role as supportive care for side effects like this.

In a review focused on photobiomodulation and cancer (Hamblin, 2018), oral mucositis is highlighted as one of the most established and effective supportive-care uses for light therapy in this setting. The key point for patients is that this is discussed as a way to support comfort and treatment tolerance — not as a cancer treatment.

Can Red Light Therapy Help with Chemotherapy-Induced Peripheral Neuropathy?

Chemotherapy-induced peripheral neuropathy (CIPN) can cause tingling, numbness, burning pain and altered sensation, most often in the hands and feet, and it can persist long after treatment ends.

One overview paper (Lodewijckx , 2020) notes CIPN is common, with rates reported around 68% in the first month after chemotherapy (falling over time, but still affecting many people months later).

The same overview explains why people are looking for new options: current approaches are largely symptom management, and results are often limited — sometimes leading to chemotherapy dose reductions as the most effective way to manage severe CIPN.

Against that backdrop, photobiomodulation (PBM) is discussed as a promising supportive therapy, but the authors stress that evidence is still limited and studies use very different protocols and outcome measures, making it harder to draw firm conclusions.

Can Red Light Therapy Prevent Peripheral Neuropathy During Chemotherapy?

A small randomised, placebo-controlled pilot trial (NEUROLASER) explored whether PBM could help prevent CIPN in breast cancer patients receiving taxane-based chemotherapy. Thirty-two patients were randomised to PBM or placebo treatment twice weekly during chemotherapy, with symptoms tracked using validated neuropathy scoring plus quality-of-life and function measures.

The main neuropathy score (mTNS) worsened over time in both groups, but several patient-reported sensory neuropathy symptoms worsened in the placebo group while remaining more stable in the PBM group. The PBM group also showed better quality-of-life scores during chemotherapy, and at follow-up there were signals favouring PBM for walking capacity (6-minute walk test) and pain (pain difference was described as borderline significant).

As a pilot study, the authors describe the results as promising, but they also highlight that larger trials are needed before PBM can be considered a reliable standard approach for prevention.

Both CIPN papers acknowledge that PBM has proliferative/repair signalling effects, which is why tumour safety has been debated; they note the broader supportive-care literature is generally reassuring but that parameters vary widely and continued monitoring is important.

Can Red Light Therapy Help with Breast Cancer?

One literature review (Robijns, 2017) looking at the use of low-level light therapy as supportive care in breast cancer — meaning support for treatment side effects rather than treating the cancer itself. Overall, the authors report the most consistent promising findings in areas like breast cancer-related lymphoedema, with additional early evidence across issues such as radiotherapy skin reactions and other symptom-management applications in specific contexts.

The review also makes a clear point: it’s hard to compare studies because protocols vary widely (device type, wavelength, dose, and how often treatment is done). The authors’ takeaway is that the therapy looks encouraging for certain side effects, but stronger evidence and clearer protocols are still needed before it can be considered reliably “standard”.

How to Use Red Light Therapy at Home

Using red light therapy at home is straightforward but involves following a few essential steps to ensure safe and effective use.

• Look for device specs: wavelength bands, irradiance at a stated distance, and recommended dose (J/cm²)

• Target the Right Areas: Decide where you want to focus treatment based on your health goals.

• Avoid use over known or suspected malignancy sites unless part of a clinician-led protocol & been cleared to do so by your medical team.

• Prepare the Skin: Clean and dry the treatment area to ensure the light penetrates effectively.

• Position the Device: Follow the manufacturer’s guidelines for distance and treatment time, typically around 15-20 minutes per session.

• Protect Your Eyes: Avoid looking directly at the light. Some devices come with eye protection, but you can also use goggles or keep your eyes closed.

• Stay Consistent: For best results, regular sessions over several weeks are recommended.

• Observe Progress: Consider tracking your progress with photos or notes to see how the therapy works for you.

Remember, while red light therapy is generally safe, it’s always wise to consult your healthcare provider, especially if you have any pre-existing conditions or are taking medication.

Red Light Therapy Product Recommendation:

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Conclusion

Red light therapy, with its diverse range of benefits and mechanisms of action, has emerged as a promising modality in the field of holistic health and wellness. While further research is needed to fully understand its potential role in cancer care, the evidence suggests that red light therapy could offer valuable support to cancer patients by mitigating certain treatment side effects. As science continues to unveil the therapeutic potential of red light therapy, it is becoming an exciting avenue for enhancing the quality of life for individuals facing cancer and other health challenges.

Interested in working with an Oncology Nutritionist for cancer prevention or following a cancer diagnosis? Get in touch to chat about how My Cancer Nutritionist can help you.

Frequently Asked Questions

• Is red light therapy safe for cancer patients?

  Across the human clinical studies reviewed where photobiomodulation (PBM) was used to prevent or manage cancer treatment toxicities, a 2019 systematic review found no signal of tumour-safety concerns in the clinical literature assessed, and most studies reported no PBM-related adverse reactions. The authors also note that longer-term follow-up is limited in many studies, so ongoing research remains important.

• Can red light therapy cause cancer cells to grow?

  This isn’t a simple yes/no question because PBM effects can vary depending on dose and context. One review explains that some cell studies have reported increased proliferation in certain cancer cell lines under certain conditions, which is why the topic has been debated.

  However, results aren’t consistent across all models. For example, a melanoma preclinical study (cells and mice) found red LED exposure reduced melanoma cell proliferation in vitro and reduced tumour growth in mice at the highest dose tested. These findings are preclinical and don’t prove the same effect occurs in people.

• Should red light therapy be used directly over a tumour?

  Because PBM can influence cellular signalling and responses depend on the protocol used, review authors commonly advise caution about direct application over tumour sites. In cancer care, PBM is most established as supportive care for treatment side effects, rather than as a cancer treatment.

• What cancer treatment side effects has red light therapy been studied for?

  Research on PBM in cancer care focuses mainly on supportive care issues such as:

  • Oral mucositis (painful mouth soreness/ulcers during chemo or radiotherapy)

  • Radiation dermatitis (radiotherapy-related skin reactions)

  • Chemotherapy-induced peripheral neuropathy (CIPN)

  • Breast cancer-related lymphoedema

• Can red light therapy help with radiation dermatitis during radiotherapy?

  A randomised clinical study in people receiving radiotherapy for head and neck cancer found that adding red light phototherapy (10 minutes, twice daily, alongside routine skin care) was linked with milder skin reactions and less skin pain, particularly during weeks 2–4 of treatment, compared with routine care alone.

• Can red light therapy help with chemotherapy-induced peripheral neuropathy (CIPN)?

  An overview paper describes PBM as a promising supportive option for CIPN, while emphasising that studies use different protocols and outcome measures, which makes firm conclusions harder.

  A randomised, placebo-controlled pilot trial (NEUROLASER) in breast cancer patients receiving taxane chemotherapy found that neuropathy worsened over time in both groups, but several patient-reported sensory neuropathy symptoms worsened more clearly in the placebo group, with signals favouring PBM for quality-of-life and some functional outcomes. Larger trials are still needed.

• Can red light therapy help with oral mucositis?

  Oral mucositis is one of the most established PBM applications in oncology supportive care. An umbrella review of randomised trials notes PBM has been included in clinical guidance for oral mucositis, reflecting a comparatively mature evidence base in this area.

• What does the breast cancer literature say for red light therapy?

  A literature review focused on breast cancer supportive care reports the most consistent promising findings in areas such as breast cancer-related lymphoedema, while also discussing PBM in relation to other treatment side effects in specific contexts. The authors highlight a key limitation: protocols vary widely (device, wavelength, dose, frequency), so stronger trials and clearer standards are still needed.

• What does the melanoma research show for red light therapy?

  The melanoma study available is preclinical (cells and mice, not people). Under that study’s specific red LED conditions, melanoma cell proliferation reduced in vitro and tumour growth reduced in mice at the highest tested dose, alongside observed changes in the tissue environment around tumours. These findings are interesting, but they do not demonstrate a clinical effect in humans.

Further Reading:

• Austin, E., Huang, A., Wang, J.Y., Cohen, M., Heilman, E., Maverakis, E., Michl, J. and Jagdeo, J. (2022) ‘Red light phototherapy using light-emitting diodes inhibits melanoma proliferation and alters tumor microenvironments’, Frontiers in Oncology, 12, 928484. doi: 10.3389/fonc.2022.928484.

• de Sousa, A.P., Paraguassú, G.M., Silveira, N.T. and dos Reis, F.A. (2017) ‘The effect of photobiomodulation in wound healing depends on the irradiation dose: results of a systematic review’, Lasers in Medical Science, 32(4), pp. 937–949.

• Ferraresi, C., Kaippert, B., Avci, P., Huang, Y.Y., de Sousa, M.V., Bagnato, V.S. and Parizotto, N.A. (2015) ‘Low-level laser (light) therapy increases mitochondrial membrane potential and ATP synthesis in C2C12 myotubes with a peak response at 3–6 h’, Photochemistry and Photobiology, 91(2), pp. 411–416. doi: 10.1111/php.12397.

• Hamblin, M.R. (2018) ‘Photobiomodulation and cancer: what is the truth?’, Photochemical & Photobiological Sciences, 17, pp. 1244–1251.

• Lodewijckx, J., Robijns, J., Claes, M., Evens, S., Swinnen, L., Lenders, H., Bortels, S., Nassen, W., Hilkens, R., Raymakers, L., Snoekx, S., Hermans, S. and Mebis, J. (2022) ‘The use of photobiomodulation therapy for the prevention of chemotherapy-induced peripheral neuropathy: a randomized, placebo-controlled pilot trial (NEUROLASER trial)’, Supportive Care in Cancer, 30(6), pp. 5509–5517. doi: 10.1007/s00520-022-06975-x.

• Myakishev-Rempel, M., Stadler, I., Brondon, P., Axe, D.R., Friedman, M., Nardia, F.B. and Lanzafame, R. (2012) ‘A preliminary study of the safety of red light phototherapy of tissues harboring cancer’, Photomedicine and Laser Surgery, 30(9), pp. 551–558. doi: 10.1089/pho.2011.3186.

• Paglioni, M.de P., Araújo, A.L.D., Arboleda, L.P.A., Palmier, N.R., Fonsêca, J.M., Gomes-Silva, W., Madrid-Troconis, C.C., Silveira, F.M., Martins, M.D., Faria, K.M., Ribeiro, A.C.P., Brandão, T.B., Lopes, M.A., Paes Leme, A.F., Migliorati, C.A. and Santos-Silva, A.R. (2019) ‘Tumor safety and side effects of photobiomodulation therapy used for prevention and management of cancer treatment toxicities: a systematic review’, Oral Oncology, 93, pp. 21–28. doi: 10.1016/j.oraloncology.2019.04.004.

• Robijns, J., Censabella, S., Bulens, P., Maes, A. and Mebis, J. (2017) ‘The use of low-level light therapy in supportive care for patients with breast cancer: review of the literature’, Lasers in Medical Science, 32(1), pp. 229–242. doi: 10.1007/s10103-016-2056-y.

• Zhang, X., Li, H., Li, Q., Li, Y., Li, C., Zhu, M., Zhao, B. and Li, G. (2018) ‘Application of red light phototherapy in the treatment of radioactive dermatitis in patients with head and neck cancer’, World Journal of Surgical Oncology, 16(1), 222. doi: 10.1186/s12957-018-1522-3.