Purpose: We aim to evaluate the effectiveness and tolerability of a sunscreen formulation containing licochalcone A (LicA) and L-carnitine (LC) as an adjuvant to adapalene in the management of acne and post-acne pigmentation (PAH).
Patients and methods: A randomized, double-blind, active comparator-controlled trial of 51 patients aged 18 years or older with a clinical diagnosis of mild-to-moderate acne vulgaris was conducted at the Hospital Sultan Abdul Aziz Shah, Universiti Putra Malaysia. The efficacy and tolerability of once-daily adapalene 1.0% were assessed during the 2-week run-in period. Subsequently, patients were randomized to receive either an add-on investigational LicA-containing sunscreen or niacinamide-containing comparator sunscreen every 4 hourly during daytime for 4 weeks. Patients were followed up at Weeks 2 and 4 to assess for improvement in acne severity, PAH, calorimetric parameters and cutaneous tolerability.
Results: Two weeks of adapalene usage significantly improved acne severity; however, up to 52% of patients experienced dryness, burning and stinging. Adding LicA-containing or comparator sunscreens was associated with further improvement in acne severity, PAH and calorimetric parameters at the study endpoint. No significant differences in the cutaneous tolerability profiles were observed between treatment groups. Notably, significantly fewer patients receiving LicA-containing sunscreen developed scaliness at Week 4 compared with those in the comparator group. In addition, more patients receiving LicA-containing sunscreen reported less dryness, burning and stinging reactions than the comparator group. Importantly, more patients receiving LicA-containing sunscreen agreed that their treatment led to excellent improvement than the comparator group; of note, one patient reported that their condition worsened with the receipt of the comparator product.
Conclusion: The concurrent use of LicA-containing sunscreen with adapalene may improve the cutaneous tolerance to adapalene among Malaysian patients.
Keywords: acne vulgaris; cosmeceuticals; retinoids; skin pigmentation; sunscreen agents.
© 2023 How et al.