Is Red Light Therapy Safe?

The Short Answer

Yes — red light therapy (RLT) is considered safe for most healthy adults when used correctly. It is non-invasive, painless, and does not use UV light, meaning it does not damage DNA or cause burns in the way that sun exposure or tanning beds can.

That said, like any therapeutic device, there are important safety guidelines to follow — and a small number of people who should exercise caution or consult a doctor first. This guide covers everything you need to know.

How Red Light Therapy Differs from Harmful Light

Not all light is equal. Here's how RLT compares to types of light that can cause harm:

UV light (100–400 nm) — damages DNA, causes sunburn, and is linked to skin cancer. Found in sunlight and tanning beds. RLT does not use UV light.
Infrared heat (above 1000 nm) — can cause thermal burns at high intensity. RLT operates at much lower wavelengths (630–880 nm) and does not generate harmful heat.
Red and near-infrared light (630–880 nm) — the wavelengths used in RLT. These penetrate tissue and stimulate cellular processes without ionising radiation or significant heat.

This is why RLT has such a strong safety profile — the mechanism of action is photochemical, not thermal or ionising.

Eye Safety

The most important safety consideration with red light therapy is eye protection. While RLT is not as damaging as UV light, prolonged direct exposure to high-intensity red or near-infrared light can cause eye strain and, over time, potential retinal damage.

Best practice:

Always wear the protective goggles or glasses provided with your device when treating areas near your face
Never stare directly into the light source
For full-body panels, close your eyes or look away from the device during sessions
For face masks (like the Kroma Glow Mask), the device is designed so light does not shine directly into open eyes — but keep eyes closed during use

Who Should Be Cautious

While RLT is safe for most people, the following groups should consult their GP or specialist before starting:

People taking photosensitising medications — certain antibiotics (e.g. tetracyclines), retinoids, and some antidepressants can increase light sensitivity. Check with your GP or pharmacist if you're unsure.
Pregnant women — there is insufficient clinical data on RLT use during pregnancy. As a precaution, avoid treating the abdomen during pregnancy.
People with diagnosed light-sensitive conditions — such as lupus erythematosus or porphyria.
People with active cancer — while RLT is not known to cause cancer, the effect of increased cellular activity on malignant tissue is not fully understood. Consult your oncologist.
People with epilepsy — flashing or pulsing light modes may be a trigger. Use steady (non-pulsing) light modes or consult your neurologist.

Common Side Effects

RLT is very well tolerated. The most commonly reported side effects are mild and temporary:

Skin warmth or redness — a temporary flush is normal, especially at closer distances. It subsides within minutes.
Eye fatigue — if goggles aren't worn. Easily avoided with proper eye protection.
Headache — rare, usually associated with sessions that are too long or too close to the device. Start with shorter sessions and build up.

There are no known serious adverse effects from correctly used consumer-grade RLT devices in the peer-reviewed literature.

How to Use Red Light Therapy Safely

Follow these guidelines for safe, effective sessions:

Start slow — begin with 5–10 minute sessions, 3–4 times per week, then increase to 10–20 minutes as tolerated.
Maintain the correct distance — typically 15–30 cm from the device. Check your specific device guidelines.
Protect your eyes — always use the provided goggles or close your eyes when treating facial areas.
Don't double up on sessions — more is not always better. One session per day per treatment area is sufficient.
Clean, dry skin — remove sunscreen, makeup, and heavy moisturisers before treatment, as some ingredients may absorb or block the light.

Device Quality and Certifications

Not all red light therapy devices are safe or effective. When choosing a device, look for:

CE marking — confirms the device meets EU/UK safety standards
Specified wavelengths — a reputable device will state exact nm values (e.g. 660 nm and 850 nm), not vague terms like "red light"
Irradiance data — the power output (mW/cm²) should be published so you can calculate safe session times
Manufacturer transparency — clear instructions, warranty, and customer support

All Kroma devices are built to these standards. Explore our range:

Kroma Glow Pro — full-body panel for skin and recovery
Kroma Radiance Pro — targeted face and body treatment
Kroma Revive Mat — full-body coverage for recovery and relaxation
Kroma Glow Mask — hands-free NIR facial mask
Kroma Hair Therapy — targeted scalp and hair growth device

The Bottom Line

Red light therapy has an excellent safety record. For the vast majority of healthy adults, it is a low-risk, high-reward wellness tool — provided you use a quality device, follow session guidelines, and protect your eyes.

If you have a specific medical condition or take regular medication, a quick conversation with your GP is all it takes to get the all-clear.

Ready to start safely? Read our introduction to red light therapy or browse our full range of Kroma devices.