A randomized controlled trial of green tea catechins in protection against ultraviolet radiation–induced cutaneous inflammation

This was a randomized controlled trial in healthy white adults with Fitzpatrick skin types I-II. In the active intervention arm, 25 participants were randomized; the trial was conducted at the Photobiology Unit, Dermatology Centre, Salford Royal Hospital in Manchester, United Kingdom, between November 2010 and August 2011.

Oral green tea catechins were given as 1,080 mg/day GTC with 100 mg/day vitamin C for 12 weeks. The regimen was delivered in capsules as 3 green tea capsules plus 2 vitamin C capsules twice daily with breakfast and the evening meal, compared with identical placebo capsules containing maltodextrin.

Oral green tea catechins with vitamin C did not meaningfully protect against ultraviolet radiation-induced cutaneous inflammation. After 12 weeks, the primary minimal erythema dose was not significantly different between the active and placebo groups, 28 mJ/cm^2 versus 20 mJ/cm^2, P = 0.47. Erythema dose-response, dermal leukocytic infiltration, CD3+ T lymphocytes, and cutaneous eicosanoid production were also not significantly improved, including PGE2 and 12-HETE measures. The authors concluded that daily supplementation for 12 weeks did not reduce UVR-induced sunburn erythema, leukocyte infiltration, or proinflammatory mediator production compared with placebo.

The trial was small, with only 25 participants in the active arm, which limits power to detect modest effects. Duration was relatively short at 12 weeks, and the population was restricted to healthy white adults with light skin types, limiting generalizability. Outcomes were largely acute UV challenge biomarkers rather than long-term clinical skin endpoints.