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Updated: Jun 6, 2026
An In Vitro Approach to Photodynamic Therapy
Published on: August 17, 2018
Photodynamic therapy with methylaminolevulinate 80 mg/g without occlusion improves acne vulgaris
Robert Bissonnette1, Catherine Maari, Simon Nigen
1Innovaderm Research Inc., Montreal, Quebec, Canada. rbissonnette@innovaderm.ca
Background:
Photodynamic therapy (PDT) with methylaminolevulinate (MAL) under occlusion is effective for the treatment of acne vulgaris but is associated with significant phototoxic side effects.
Objective:
To evaluate the safety and efficacy of topical MAL with or without occlusion followed by red light exposure in patients with facial acne vulgaris.
Patients/Methods:
Forty-four patients with facial acne vulgaris were randomized to receive four MAL applications (80 mg/g) at two-week intervals with occlusion on either the right or left side followed 90 minutes later by either 25 or 37 J/cm2 of red light.
Results:
At 18 weeks after the first MAL-PDT treatment, the percentage of inflammatory lesions was reduced by a median of 31.7, 59.4, 58.1 and 55.8 percent for patients randomized to 25 J/cm2 without occlusion, 25 J/cm2 with occlusion, 37 J/cm2 without occlusion and 37 J/cm2 with occlusion respectively. MAL-PDT was, in general, well tolerated and only two patients discontinued their participation due to adverse events.
Conclusion:
PDT with MAL at 80 mg/g without occlusion reduces the number of inflammatory lesions in patients with facial acne vulgaris.
