Red light therapy Series 2: What are the key safety considerations, contraindications, or risks of red-light therapy?

By Reine DuBois, Integrative Naturopath and Clinical Director, The Byron Bathhouse

Red-light therapy (RLT), also known as photobiomodulation (PBM), is generally regarded as a safe, non-invasive and well-tolerated therapy when used correctly.
Unlike ultraviolet (UV) light, RLT does not damage DNA or increase the risk of skin cancer. Its safety profile is one of the reasons it has become a mainstay in both clinical and home wellness settings.

However, as with any therapeutic tool, there are important precautions and contraindications to ensure safe and effective use.

1. When Red-Light Therapy Should Be Avoided

Certain medical conditions and life stages require caution or complete avoidance:

• Active cancer or suspicious lesions: Because RLT stimulates cellular repair and growth, it should be avoided over active tumours or precancerous areas. People with a history of cancer should seek guidance from their oncologist before use.
• Photosensitive conditions: Those with lupus, porphyria, or albinism may experience heightened skin sensitivity and should avoid RLT.
• Seizure disorders (epilepsy): Flickering light emitted by some older or unregulated devices can trigger seizures. Always check device specifications if you have a history of epilepsy.
• Pregnancy: While there is no conclusive evidence of harm, due to limited research RLT is best avoided over the abdomen or lower back during pregnancy.
• Recent burns, open wounds or active infections: Wait until the skin has begun healing; using RLT too soon may delay recovery or spread bacteria.
• Fever or acute illness: Because RLT slightly raises body temperature, it is best postponed during systemic infections or febrile episodes.

2. Sensitive Areas and Local Precautions

• Eyes: Direct exposure to RLT can cause eye injury. Protective goggles are essential, particularly with high-intensity devices or near-infrared wavelengths. Those with glaucoma, cataracts, or recent eye surgery should avoid treating the face without medical supervision.
• Thyroid gland: People with hyperthyroidism or on thyroid medication should avoid applying RLT directly over the neck.
• Tattoos: Red or yellow pigments can absorb light differently, occasionally leading to fading, colour change or irritation. Cover tattooed skin or reduce exposure time.

3. Medication and Light Sensitivity

Some drugs can increase photosensitivity, raising the risk of redness or burns. Common examples include:

• Certain antibiotics (e.g., tetracyclines).
• Retinoids or acne medications (e.g., isotretinoin).
• Some anti-inflammatories and diuretics.

Always check your medication leaflet and consult your prescribing practitioner if unsure.

4. Risks Linked to Dosage and Device Use

Most adverse effects arise from incorrect dosing or poor-quality devices rather than the light itself.

• Biphasic dose response: RLT follows the “less is more” principle. An optimal dose triggers repair; too much can slow healing or cause irritation.
  • Overuse may cause redness, dryness, or rebound inflammation.
  • Underuse may fail to achieve a therapeutic effect.
• Excess heat: While RLT is non-thermal, powerful near-infrared devices can build heat, especially when used for long periods or in conjunction with sauna therapy.
• Brain overheating: When combining light and heat therapies, avoid raising head temperature excessively. Symptoms like dizziness, lethargy, or nausea indicate overheating.
• Device quality: Choose devices with reputable medical safety certifications (e.g., IEC 60601-1). Beware of misleading claims such as “FDA registered” without true device approval.

5. Professional Guidance Matters

Even though RLT is available for home use, professional assessment can determine appropriate dosage, wavelength, and treatment duration for your condition. Integrative clinics like The Health Lodge use medical-grade equipment under clinical supervision, ensuring treatments are delivered safely within the optimal therapeutic window.

In Summary

Red-light therapy is an exceptionally safe and effective tool for reducing inflammation, pain, and skin aging, but precision and awareness are key.
Avoid use during active illness, over tumours or the thyroid, and protect your eyes. Work with a trained practitioner to ensure your exposure levels are both safe and therapeutic.

References:

1. Hamblin MR. BBA Clin. 2016;6:113–124.
2. Chung H et al. Ann Biomed Eng. 2012;40(2):516–533.
3. Jenkins PA, Carroll JD. Lasers Surg Med. 2011;43(8):813–826.