What are the side effects of Aminolevulinic acid?
Last updated September 7, 2026.
**Most side effects of aminolevulinic acid are local skin reactions where it was applied plus a short period of extreme sensitivity to light.** Aminolevulinic acid only becomes active when light hits it, so the reaction you feel is the treatment working on sun-damaged cells. With the topical forms used for actinic keratoses, expect stinging or burning during the light session, then redness, swelling, scaling, and crusting for several days to a few weeks. Your treated skin stays very light sensitive for roughly 40 hours, including bright indoor lamps and light through windows, so sunscreen alone is not enough and clothing plus shade matter more. The oral form given before brain tumor surgery has a different profile, including nausea, chills, low blood pressure, and liver enzyme changes. Call your clinician if blistering spreads, pain keeps rising after day three, or you see pus, spreading warmth, or fever.
What to do
- Block light, not just sun: For about 40 hours after a topical dose, wear a wide brim hat, long sleeves, or a dressing, and avoid bright lamps, exam lights, and window light.
- Skip the sunscreen shortcut: Sunscreen does not protect against the visible light that activates this drug, so physical covering is what actually prevents a burning reaction.
- Plan the calendar: Book treatment when you can stay indoors afterward, and expect the treated skin to look red and crusted for several days before it smooths out.
- Soothe simply: Cool compresses and plain moisturizer help; avoid retinoids, acids, and scrubs on the area until healing is complete.
- Flag the warning signs: Contact your clinician for spreading blisters, pus, fever, worsening pain after day three, or eye pain and light sensitivity that will not settle.
- Share your full med list: Other photosensitizing drugs such as some antibiotics, diuretics, and retinoids can intensify the reaction, so review them before treatment.
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