Red light therapy is non-UV, but certain medications and skincare actives can flip the switch, turning beneficial light into a blister-causing irritant. Here is what you need to know.
Photosensitivity refers to a heightened reaction to light. While we normally worry about this with the sun (UV rays), intense visible light from LED masks can also trigger reactions in sensitised skin. This is known as drug-induced photosensitivity.
If a medication bottle says "Avoid Sunlight" or shows a sun symbol, do not use your LED mask until you have finished the course and waited at least 5-7 days.
Many common prescriptions and over-the-counter drugs in the UK carry this risk. This list is not exhaustive, but covers the most frequent offenders.
| Drug Category | Common Names | Risk Level |
|---|---|---|
| Antibiotics | Doxycycline, Tetracycline, Ciprofloxacin, Lymecycline | HIGH |
| Acne Medication | Isotretinoin (Roaccutane), Tretinoin | HIGH |
| Diuretics | Furosemide, Hydrochlorothiazide | MODERATE |
| NSAIDs (Painkillers) | Ibuprofen, Naproxen (High doses) | LOW / MILD |
| Antifungals | Griseofulvin, Voriconazole | MODERATE |
It's not just pills. What you put on your face matters. While not all of these cause "drug-induced" sensitivity, they thin the skin barrier, making it more reactive to heat and light energy.
Retinoids increase cell turnover. While low-strength retinol is often fine used at night (with LED in the morning), prescription Tretinoin can make skin extremely fragile.
Rules: Avoid LED immediately after applying. See our Retinol Guide.
Glycolic and Lactic acid strip the outer layer of dead skin cells (the stratum corneum). This reduces your natural protection against light intensity.
Rules: If you use strong peels (e.g., The Ordinary Peeling Solution), skip LED for 24 hours.
Bergamot, Lime, and Lemon oils contain furocoumarins, which react strongly with light (phytophotodermatitis). Avoid serums heavily scented with these oils before treatment.
If you use an LED mask while photosensitised, you won't necessarily feel a "burn" immediately. The reaction is often delayed.