Treatment of Acne‐Induced Facial Post‐Inflammatory Hyperpigmentation With a New 2‐ MNG ‐Containing Routine Versus a Thiamidol‐Containing Routine—A Monocentric Prospective Double‐Blind Randomized Comparative Trial

Background Acne‐induced post‐inflammatory hyperpigmentation (PIHP) is a frequent condition. 2‐mercaptonicotinoyl glycine (2‐MNG) is an innovative anti‐pigmenting molecule. Aims The aim of this study is to compare the efficacy and tolerability of two routines in the treatment of PIHP: 2‐MNG‐containing serum + SPF50+/UVA sunscreen versus Thiamidol‐containing serum + SPF50+/UVA sunscreen. Patients/Methods A prospective, randomized, double‐blind, parallel‐group controlled trial was conducted in Mauritius (February–October 2023). Adults with phototypes III–VI, mild facial acne, and moderate‐to‐severe post‐acne PIHP were recruited. Participants received routine A (2‐MNG‐containing serum+sunscreen) or B (Thiamidol‐containing serum+sunscreen) for 84 days. The primary outcome was the change in PAHPI global score at D84 between routines. Exploratory outcomes included PAHPI global score at earlier time points, as well as PAHPI subscores, lesion darkness, subjective global assessment, color measurements, and stigmatization at D28, D56, and D84. Results Eighty‐four patients were screened and included, and 77 were analyzed. At D84, both routines improved the PAHPI global score ( p < 0.001 vs. D0 for each routine, mean difference between routine A and B at D84: −0.39 ± 1.95, 95% confidence interval [−1.27;0.50], routine A showed no inferiority vs. routine B but did not show superiority), PAHPI lesion number ( p < 0.01), mean lesion darkness ( p < 0.001), and stigmatization ( p < 0.001 for routine A at D56 and for routine B at D84). Routine A was superior to routine B regarding PAHPI lesion number decrease ( p = 0.03), color measurements at D84 ( p < 0.05), and satisfaction. Conclusions Both routines improved post‐acne PIHP and were well tolerated. The 2‐MNG‐containing routine was not inferior to the Thiamidol‐containing routine and displayed better satisfaction and results on several objective parameters.