2-MNG-Containing Depigmenting Serum is Effective for Post-Inflammatory Hyperpigmentation

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Researchers tested the efficacy of a novel depigmentation agent 2-mercaptonicotinoyl glycine (2-MNG/Melasyl) for treating post-inflammatory hyperpigmentation (PHP).¹ The dermocosmetic serum formulation was tested on its own without sunscreen or any other anti-dark spot treatments. Positive results were demonstrated via clinical evaluation, patient-reported outcomes, and objective instrumental assessments.

The open-label, single-site study took place in Mauritius, East Africa between April and August 2023. It included 32 participants between the ages of 18 and 50 with a Fitzpatrick phototype between IV and VI. Nearly all were female.

Each patient had mild acne with a Global Acne Evaluation (GAE) score of 2 and less than 9 lesions as well as moderate to severe PIHP, which was indicated by a Post Acne Hyperpigmentation Index (PAHPI) score > 10. The average PAHIPI at baseline was 13.9.

The product contained 0.5% 2-MNG, 10% niacinamide, Cystoseiratamariscifolia extract, lipohydroxy acid, carnosine, retinyl palmitate, and dipotassium glycyrrhizate. The serum was applied to the entire face twice a day for 3 months.

Researchers assessed the PAHPI score, mean darkness of lesions, GAE score, and other colorimetric measurements at baseline, 14, 28, 56, and 84 days. Self-perceived marks in efficacy, tolerability, and satisfaction were also noted.

At day 84, a 15.8% decrease in PAHPI score was recorded (p < 0.05). An overall improvement in PAHPI score was reported in 75% of participants. A decrease in lesion intensity was noted as early as day 56. There was a significant mean change of 13.7% in lesion size between baseline and day 84.

In 84.4% of patients, the mean darkness clinical evaluation improved by day 28 with a score of 5.1 (p < 0.05). This improved to 4.6 (p < 0.05) at day 56 and 4.0 (p < 0.05) at day 84, respectively, 

Decreases in acne were seen as early as day 14. The highest reduction in GEA score was noted at day 84, with a 43.8% decrease compared to baseline (p < 0.05) and a mean value of 15.1.

According to surveys, patients reported improved appearance, well-being, and quality of life. By day 84, most noted that their PIHP had moderately improved. Global stigmatization scores also saw a 30.6% by the conclusion of the trial. Participants who had previously hidden the affected skin or even refused to go out in public were less self-conscious.

“These insights have the potential to help clinicians to develop targeted patient management strategies, including evidence-based interventions,” the authors wrote. “Healthcare providers could consider the effects of PIHP on health-related QOL and educate patients on available treatment options.”

The serum was also well tolerated with no adverse effects. According to cosmetic and efficacy evaluation questionnaires, the product had a lightweight pleasant texture that was gentle and suitable for all skin types. Patients noticed a more even, smooth, and radiant skin tone with lighter spots that grew smaller and less visible. Nearly all of the patients preferred the product formulation to their current anti-dark spot treatment, with better performance and tolerability.

The small sample size and lack of a control group are considered to be potential limitations. Further research with a larger population and a split-face design could be helpful. Additionally, this study did not provide additional sunscreen to patients in order to test the serum as a stand-alone treatment. These positive results suggest that using this product with sun protection could provide even more benefits.

Acne-induced PIHP can last at least 1 year and up to 5 years.² Hydroquinone, arbutin, kojic acid, and niacinamide are currently the most commonly used topical agents but can potentially trigger dermal sensitivity and irritation. Although this study only focused on acne-induced PIHP, investigators encourage the use of this 2-MNG serum in the treatment of other hyperpigmentation disorders such as solar lentigo or melasma.

References

1. Demessant-Flavigny AL, Petkar G, Jodun D, Le Dantec G, Le Floc'h C, Kerob D. Efficacy of a 2-MNG-Containing Depigmenting Serum in the Treatment of Post-Inflammatory Hyperpigmentation. J Cosmet Dermatol. Published online December 26, 2024. doi:10.1111/jocd.16735

2. Abad-Casintahan F, Chow SK, Goh CL, et al. Frequency and characteristics of acne-related post-inflammatory hyperpigmentation. J Dermatol. 2016;43(7):826-828. doi:10.1111/1346-8138.13263