Aminolevulinic Acid Topical: Uses, How It Is Applied, Side Effects
Last updated September 7, 2026.
Aminolevulinic acid topical is a photosensitizing agent used as the first half of photodynamic therapy, a two-step in-office skin treatment. After it is applied to the skin, sun-damaged and precancerous cells take it up and convert it into a compound that reacts strongly to a specific wavelength of light. When your clinician shines blue or red light on the area, that reaction destroys the abnormal cells while leaving most normal skin intact. The safety point that matters most is light avoidance: your treated skin stays highly light-sensitive for about 40 to 48 hours after application, so sunlight and bright indoor light can cause a severe burning reaction even after you leave the office.
What does it treat?
Aminolevulinic acid topical is approved to treat actinic keratoses, the rough, scaly, sandpapery spots that develop on skin with years of sun exposure, usually on the face, scalp, ears, forearms, and backs of the hands. Levulan Kerastick, a 20 percent solution, is applied to individual actinic keratosis lesions on the face, scalp, or upper extremities and activated with blue light. Ameluz, a 10 percent gel, is used for mild to moderate actinic keratoses of the face and scalp, including field treatment of a whole sun-damaged area rather than single spots, and is also approved for superficial basal cell carcinoma when surgery is not the preferred option. It is not a home cream, and it is not used for melanoma, deeper skin cancers, or ordinary wrinkles.
How do you take it?
This is applied by a health care professional in a clinic, not by you at home. With Levulan Kerastick, the contents of one applicator are dabbed onto the target lesions at one session, and you return for blue light illumination 14 to 18 hours later for face and scalp lesions, or 3 hours later under a dressing for upper extremity lesions; the blue light session runs about 17 minutes, and a lesion that has not cleared can be treated again no sooner than 8 weeks. With Ameluz, up to 2 g of gel, which is one tube, is spread about 1 mm thick over the lesions and roughly 5 mm of surrounding skin, covered with a light-blocking dressing for 3 hours, then illuminated with red light in the same visit; actinic keratoses that have not fully cleared can be retreated after 3 months, and superficial basal cell carcinoma is treated twice, one week apart. There are no food rules and nothing to swallow, so there is no daily ceiling to track and no missed-dose rule in the usual sense. If you cannot make the light appointment after a Levulan application, do not simply skip it: call the clinic to reschedule and keep the treated skin covered and out of light for at least 40 hours. Call the clinic before your next session if you get blistering, an open sore, spreading redness with pus or fever, or pain that keeps getting worse after the first few days.
Side effects to know
- Common: Expect stinging, burning, redness, swelling, itching, and then scaling or crusting of the treated skin, with the burning strongest during the light session and the skin usually settling down over about one to four weeks.
- Serious: Stop light exposure and get medical help for a severe photosensitivity reaction, meaning deep burn-like pain, blistering, or open erosions after sun or bright light hits the treated area, and for signs of infection such as spreading redness, warmth, pus, or fever. Get emergency help for an allergic reaction with hives, swelling of the lips, tongue, or throat, wheezing, or trouble breathing, which is a particular concern with Ameluz because it contains a soy-derived ingredient.
Who should not take it?
Aminolevulinic acid is not used if you have porphyria, a known allergy to porphyrins, or cutaneous photosensitivity to the wavelengths used in treatment, and Ameluz is also avoided if you are allergic to soya or peanut. Tell your clinician if you take medicines that raise light sensitivity, such as tetracyclines, sulfonamides, thiazide diuretics, sulfonylureas, phenothiazines, griseofulvin, or St. John's wort, since these can worsen the reaction. It should not get into your eyes or onto mucous membranes, and it has not been established as safe or effective in children. In pregnancy there are no adequate human data, though systemic absorption from the skin is low; current FDA labeling has no pregnancy warning that rules the drug out, so the decision is made case by case with your clinician. For breastfeeding, there is no information on whether the drug passes into human milk, so discuss timing and whether to pump and discard before your session. Drinking alcohol does not interact with the treatment, but the Levulan solution itself contains alcohol and is flammable, so keep it away from flames, sparks, and smoking while it is on your skin and still wet.
When is it an emergency?
True emergencies with this medicine are rare, since very little enters the bloodstream. Call 911 if you collapse, have trouble breathing, or develop swelling of the face, lips, tongue, or throat with hives after treatment, which can signal anaphylaxis. Call Poison Control at 1-800-222-1222 right away if anyone swallows the solution or gel or if it gets into the eyes, and rinse the eyes with water while you call. Call 911 or go to an emergency department for a large burn-like injury with widespread blistering after sun or bright light exposure, for a rapidly spreading skin infection with fever, or for sudden eye pain and vision change after light exposure.
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Common questions
What is the most that can be used at one visit?
With Ameluz gel, the limit is 2 g, which is one tube, per treatment session. With Levulan Kerastick, one applicator is used per session and the solution goes only on the target lesions. There is no daily total for you to count at home, because a clinician applies the product and you do not take any of it yourself. Actinic keratoses that have not cleared can be treated again after 8 weeks with Levulan or after 3 months with Ameluz, and superficial basal cell carcinoma is treated twice one week apart.
Can I drink alcohol during this treatment?
Drinking alcohol does not interact with aminolevulinic acid and does not change how the light therapy works. The alcohol issue is on your skin, not in your glass: the Levulan Kerastick solution is alcohol-based and flammable while it is wet. Keep away from open flames, sparks, cigarettes, and vaping until it has dried. If you drink heavily, mention it anyway, since it affects healing and skin cancer risk overall.
Is it safe during pregnancy or breastfeeding?
There are no adequate studies of aminolevulinic acid topical in pregnant people, so the FDA labeling does not confirm safety. Very little is absorbed through the skin, which is why clinicians often consider it reasonable when treatment cannot wait, but many will suggest postponing an elective actinic keratosis treatment until after delivery. For breastfeeding, it is not known whether the drug appears in human milk. Tell your clinician before the appointment so you can decide together, including whether to pump and discard milk around the session.
Do I need to avoid food or take anything with food?
No. This medicine goes on your skin and is not swallowed, so there are no food or fasting rules and no timing around meals. Eat and drink normally before and after your visit. The only preparation your clinician may ask for is to shave or gently clean the area and to skip lotions, sunscreen, or makeup on the treatment site that day.
What are the signs that something has gone wrong after treatment?
The expected course is stinging and burning during the light session, then redness, swelling, and crusting that fade over one to four weeks. Warning signs are different: deep burn-like pain with blistering or open erosions after light exposure, redness that spreads outward with warmth, pus, or fever, or pain that increases after the first few days instead of easing. Eye pain or vision change after light exposure also needs urgent attention. If the product is swallowed or gets in the eyes, call Poison Control at 1-800-222-1222, and call 911 for trouble breathing or swelling of the lips, tongue, or throat.
Which medicines and products interact with it?
Anything that makes your skin more sensitive to light can amplify the reaction. That includes tetracycline and doxycycline, sulfonamide antibiotics, thiazide diuretics, sulfonylureas for diabetes, phenothiazines, griseofulvin, and the herbal supplement St. John's wort. Bring your full medicine and supplement list to the visit so your clinician can decide whether to adjust timing. Also mention any allergy to soya or peanut, since Ameluz contains a soy-derived ingredient, and any history of porphyria or reactions to porphyrins, which rule out this treatment.