Efficacy evaluation of a topical formulation containing green tea and willow bark extract for acne and post-acne mark reduction in Indian subjects: a double-blind clinical study

Abstract

Background: Consumers with acne-prone skin often experience recurring pimples, inflammation, uneven texture and stubborn post-acne dark marks linked to post-inflammatory hyperpigmentation (PIH). These concerns affect skin clarity and even tone, highlighting the need for gentle, effective topical solutions. This clinical study evaluates the efficacy of a topical formulation containing green tea extract actives (5%) and willow bark extract (2%) in reducing acne and acne marks over a 7-day period.

Methods: A double-blind, non-comparative clinical study was conducted on 36 Indian subjects (18 males, 18 females; aged 18–35 years) with mild-to-moderate acne and oily to combination skin. The test product was applied twice daily for 7 days. Efficacy was assessed using the Michaelsson acne severity index, lesion analysis, mexametry for PIH and subject self-evaluation. Safety was evaluated through dermatological assessment of irritation parameters. Measurements were recorded at baseline, day 1, day 3 and day 7.

Results: The test product demonstrated a time-dependent reduction in melanin index associated with acne-induced PIH, with mean reductions of 0.11%, 0.50% and 0.77% at day 1, day 3 and day 7, respectively. By Day 7, improvement in PIH-related acne marks was observed in up to 100% of subjects. Acne severity significantly reduced (-25.72%, p<0.001) by day 7, with notable decreases in papule and pustule redness and size and in comedones size. No adverse events or irritation were reported and 100% of subjects agreed the product reduced acne and acne marks

Conclusions: The formulation effectively reduced acne, PIH-related acne marks and melanin index within 7 days, with good tolerability and no reported irritation or adverse events.