Can Red Light Therapy Cause Cancer? What the Evidence Says
No research has found that red light therapy causes cancer. Red and near-infrared light contain no ultraviolet, which is the part of sunlight and sunbeds that damages DNA in skin cells and leads to skin cancer. The American Academy of Dermatology, UCLA Health and Harvard Health all say the same thing in plain words. Hospitals also use red light on cancer patients, to prevent the mouth sores caused by chemotherapy and radiotherapy, and follow-up studies of those patients have found no harm to survival. Two cautions sit alongside that. Nobody has followed home users for many years, so long-term effects are unstudied. And specialists advise against shining light directly over a known or suspected tumour, so anyone who has or has had cancer should ask their oncology team first. This article covers the evidence, the confusions with sunbeds and with light-based cancer treatments, and the questions about moles, heat and blue light.
Can red light therapy cause cancer?
There is no evidence that it does. Dermatology and hospital sources say so directly, while noting that long-term use has not been studied.
| Source | What it says |
|---|---|
| American Academy of Dermatology | Unlike ultraviolet light, "research hasn't found that red light can cause any type of cancer" |
| UCLA Health, 2025 | "No research has suggested that red light can cause cancer" |
| Harvard Health, 2025 | Unlike ultraviolet light, red light therapy "hasn't demonstrated such risks" |
| Cleveland Clinic | Red light therapy does not use the cancer-causing ultraviolet light of the sun or tanning booths |
Sources: AAD, UCLA Health, Harvard Health, Cleveland Clinic. The AAD adds that red light appears safe in the short term and that the long-term effects on skin are not yet known. That is the fair summary: no sign of a cancer risk, and no decades-long study either.
Why does UV cause skin cancer, and how is red light different?
Ultraviolet light is absorbed by DNA and damages it. Red and near-infrared light carry less energy and are not absorbed by DNA in that way.
Cancer Research UK explains that too much UV from the sun or sunbeds damages the DNA in skin cells, and that damage building up over time can make cells grow out of control. Cancer Research UK. In 2009 the World Health Organization's cancer agency classified UV tanning devices as carcinogenic to humans, its highest category, and reported that melanoma risk rises by 75% when sunbed use starts before age 30. IARC. Red light sits at the other end of the visible spectrum, and near-infrared beyond it. A 2025 consensus of 21 dermatology experts stated that red light photobiomodulation does not induce DNA damage. Consensus.
This is also why a red light bed and a sunbed are different things, even when they stand side by side in the same salon. Red light therapy beds explains how to tell them apart.
What have the safety studies found?
The human trials tested how much red light skin can take, and found the limit was blistering at very high doses, which took 90 minutes or more under the lamp. Studies in cancer patients found no sign of harm to the cancer.
| Study | What they did | What they found |
|---|---|---|
| Jagdeo 2019, 115 healthy volunteers, two randomised trials | 633 nm red LED on the forearm, three times a week for three weeks, at rising doses of 160 to 640 J/cm² | Safe up to 320 J/cm² for skin of colour and 480 J/cm² for white skin; the limit was blistering or lasting redness. No serious side effects |
| Paglioni 2019, systematic review of 27 studies | Light therapy used to manage the side effects of cancer treatment | Concluded that its use "does not lead to the development of tumor safety issues" |
| Genot-Klastersky 2020, 361 people with head and neck cancer | 222 had light therapy during radiotherapy, 139 did not | No statistically significant difference in survival, recurrence or progression between the two groups |
| Myakishev-Rempel 2012, mice with UV-induced skin tumours | 670 nm red LED twice a day for 37 days | The light had "no measurable effect" on tumour growth |
Sources: Jagdeo, Paglioni, Genot-Klastersky, Myakishev-Rempel. For scale, the 480 J/cm² dose in these trials took 90 minutes under the lamp. These studies were about tolerance and about patients treated by clinicians; none followed home users for years.
Can people with cancer use red light therapy?
Only with their oncology team's agreement, and not over the tumour. Light therapy is used in cancer care, but under clinical direction.
The international supportive-care guideline recommends red light inside the mouth, given by clinicians, to prevent the mouth sores that chemotherapy and radiotherapy cause. Guideline. The World Association for Photobiomodulation Therapy puts both halves in one sentence: the therapy is safe for patients with cancer, but it "does not recommend direct treatments over the tumor site". Position paper. The reason for the caution is that lab results on cancer cells are mixed, so the standard advice is to keep light off any known or suspected tumour.
If you have, or have had, cancer, your oncology team decides. Brown University Health gives the same advice to anyone with a history of skin or eye cancer. Brown Health.
Is red light used to treat skin cancer?
Only together with a drug, in a clinic. That is photodynamic therapy, and the drug does the work.
In photodynamic therapy a doctor applies a medicine that makes abnormal cells extremely sensitive to light, then shines red or blue light on the area to switch it on. The US National Cancer Institute lists it for sun-damaged precancerous patches and some skin cancers. NCI. A Stanford dermatologist put the distinction in one line: "Red light, alone, does not destroy skin cancer." Stanford Medicine. A home red light device, with no drug, does not treat skin cancer, and there is no evidence that it causes it.
Can you use red light therapy over moles?
We found no guidance on it from any dermatology body, and no evidence that red light changes moles. The rule about moles is the same with or without a light device.
A mole that is new, changing in size, shape or colour, bleeding or itching needs a dermatologist, whatever else you are doing with your skin. If you have many moles or a history of skin cancer, mention the device at your next skin check.
Does the heat or infrared cause cancer?
No source links timed LED sessions to it. The heat-related skin condition doctors describe comes from pressing skin against a hot source for months or years.
That condition, erythema ab igne, is a net-like brown or red pattern caused by long-term heat from things such as hot water bottles, heating pads and space heaters; in rare, long-standing cases skin cancers have formed in it. DermNet. The medical descriptions of the condition do not name LED light devices as a cause. Keeping sessions timed and stopping if the skin feels hot is the sensible habit, and if any device ever leaves a net-like pattern on your skin, stop and see a doctor.
Does blue light therapy cause skin cancer?
We found no source that says it does. Blue light is visible light, not ultraviolet.
The Cleveland Clinic notes that LED light therapy does not use UV. Cleveland Clinic. Blue light has its own, different cautions, mainly that it can darken medium and darker skin; blue light therapy covers them.
How do you use red light therapy sensibly?
Stay inside the device's timer and limits, protect your eyes, and check with a doctor if you have a cancer history or take light-sensitising medication.
- Keep to the manual. More light is not better, and the blistering seen in the dose trials came at 480 J/cm² and above.
- No UV. Check that a device lists its wavelengths. Red is about 620 to 700 nm and near-infrared about 800 to 1100 nm; ultraviolet is below 400 nm.
- Keep sunscreen. Red light does not protect against the sun, which is the real skin cancer risk.
- Cancer history. Ask your oncology team before you start.
- Changing mole or sore that will not heal. See a dermatologist; do not treat it with light.
Is red light therapy safe covers side effects and who should not use it.
Kivorla devices and UV
Neither Kivorla device emits ultraviolet. Their wavelengths run from blue through red to near-infrared.
The 4-Wavelength Red Light Therapy Mask uses 460, 665, 850 and 1064 nm, with a timer of 5, 10 or 15 minutes and a limit of 20 minutes a day. The 9-Spectrum Red Light Therapy Panel uses nine wavelengths from 480 to 1060 nm, each dimmable, with a timer of 1 to 30 minutes and a surface that stays at or below 40°C. They are general wellness devices: they do not treat or prevent cancer.
Read the precautions before ordering, since returns are accepted within 30 days, less a 10% restocking fee if the device is unopened with its seals intact, or 20% if it is opened but undamaged and complete. Standard shipping to the US, UK and Germany is free.
Kivorla devices are general wellness devices, not medical devices, and do not diagnose, treat or prevent cancer. If you have or have had cancer, or have a mole or patch of skin that concerns you, speak to your doctor.