The goal of this randomized, triple-blind, vehicle-controlled clinical trial is to evaluate whether topical 7.5% dapsone gel is effective for treating mild-to-moderate acne vulgaris in adults.

The main questions are:

• Does dapsone gel improve global acne severity compared with a matched vehicle gel?
• Does dapsone gel improve comedonal and papulopustular acne severity?
• Does dapsone gel reduce erythema and melanin indices measured with a Mexameter, and sebum index measured with a Sebumeter?
• Does treatment with dapsone gel improve patients' acne-related quality of life?

Researchers compared once-daily dapsone gel with a matched vehicle gel without the active ingredient.

Participants:

• Applied either dapsone gel or vehicle gel once daily for 8 weeks
• Attended clinic visits at baseline, week 4, week 8, and week 12
• Had acne severity assessed using the Global Acne Grading System and Plewig and Kligman comedonal and papulopustular stages
• Had erythema and melanin measured with a Mexameter, and sebum measured with a Sebumeter at predefined facial sites
• Completed an acne quality-of-life questionnaire at baseline and week 8
• Had standardized photographs taken at each visit

Treatment was continued for 8 weeks, followed by a 4-week treatment-free follow-up through week 12.

This is a prospective, randomized, triple-blind, vehicle-controlled clinical trial designed to evaluate the clinical efficacy of topical 7.5% dapsone gel in adults with mild-to-moderate acne vulgaris. The study also investigates the effects of topical dapsone on skin biophysical parameters using standardized instruments: erythema and melanin indices measured with a Mexameter, and sebum index measured with a Sebumeter.

Two parallel arms were included: one group applied topical 7.5% dapsone gel once daily, and the other applied a matched vehicle gel identical in base, tube, and packaging but without the active ingredient. Randomization was performed using a pre-generated computer-based randomization sequence. Participants, dispensing investigators, outcome assessors, and data analysts were blinded to treatment allocation.

Participants attended clinic visits at baseline, week 4, week 8, and week 12. Treatment was applied for 8 weeks, followed by a 4-week treatment-free follow-up period through week 12. At each visit, standardized digital photographs were taken, and acne severity was assessed using the Global Acne Grading System (GAGS), lesion counts used to assign Plewig and Kligman comedonal and papulopustular stages, and standardized clinical evaluation. At each visit, Mexameter readings for erythema and melanin and Sebumeter readings for sebum were obtained at three predefined facial sites: right cheek, left cheek, and forehead. Triplicate measurements were obtained at each site after a standardized acclimatization period. The Turkish-validated Gupta Acne Quality of Life Scale was administered at baseline and week 8.

The primary objective was to determine whether topical 7.5% dapsone gel reduces inflammatory lesion burden compared with matched vehicle at week 8. Secondary evaluations included changes in Global Acne Grading System (GAGS) total score, comedonal acne stage, sebum index, erythema index, melanin index, acne-related quality of life, and local cutaneous adverse events. By combining standardized clinical assessments, patient-reported outcomes, and objective biophysical measurements, this trial aimed to evaluate the clinical and biophysical effects of topical 7.5% dapsone gel in acne vulgaris.

Inclusion Criteria:

• Adults aged 18 to 50 years with a clinical diagnosis of mild-to-moderate acne vulgaris.
• No systemic or topical acne treatment within the past 1 month (30 days).
• Able and willing to provide written informed consent.

Exclusion Criteria:

• Pregnancy or breastfeeding.
• Systemic retinoid or systemic antibiotic use within the past 6 months.
• Active dermatologic or systemic disease that could interfere with study participation or outcome assessments.
• Known hypersensitivity to dapsone or any component of the study product.

Participants, dispensing investigators, clinical outcome assessors, photographic evaluators, and data analysts were blinded to treatment allocation. Study products were identical in appearance, base, tube, and packaging and were labeled with coded allocation identifiers.