Epigallocatechin-3-gallate (EGCG), a major catechin found in green tea, has been investigated for its potential effects in rheumatoid arthritis (RA) due to its anti-inflammatory and antioxidant properties. Preclinical studies, primarily in vitro and in animal models, have demonstrated that EGCG can inhibit the production of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6, all of which play key roles in the pathogenesis of RA. EGCG has also been shown to suppress the activation of NF-κB, a transcription factor central to inflammatory processes, and to reduce the proliferation of synovial fibroblasts that contribute to joint destruction in RA.

While these mechanistic studies provide a biological rationale for the use of EGCG in supporting RA management, human clinical evidence is limited. There are a few small-scale clinical studies and pilot trials suggesting possible benefits in symptom reduction and inflammatory marker modulation, but results are preliminary and not robust enough to support routine clinical use. No major guidelines recommend EGCG as a standard treatment for RA, and its use remains adjunctive or experimental.

In summary, EGCG use for RA is supported by promising preclinical data and limited early clinical research, justifying a moderate-low evidence rating. Further large-scale, well-controlled human trials are necessary to establish efficacy and safety in this context.