Green tea contains polyphenolic compounds, particularly epigallocatechin-3-gallate (EGCG), which have been studied for their anti-inflammatory and antioxidant properties. Several in vitro (cell-based) and animal studies have suggested that EGCG can modulate immune responses and inhibit the proliferation of keratinocytes, both of which are central to the pathophysiology of psoriasis. For example, a study published in Experimental Dermatology (2007) demonstrated that topical EGCG application reduced psoriatic-like skin lesions in mice. In addition, some small pilot clinical trials have explored the topical and oral use of green tea extracts in psoriasis patients, reporting improvements in skin lesions and inflammation markers, though these studies are limited in scale and quality.

However, large, high-quality randomized controlled trials in humans are lacking, and there is not yet sufficient evidence for green tea or its antioxidants to be recommended as primary or adjunct therapy for psoriasis in clinical guidelines. The evidence supporting its use is promising but preliminary, and more rigorous clinical research is needed to confirm efficacy and safety. Traditional use of green tea is not specifically linked to psoriasis, so the justification for its use is based on early scientific findings rather than historical precedent.