Katiyar, S. K., Afaq, F., Perez, A., & Mukhtar, H. (2001). Green tea polyphenol (-)-epigallocatechin-3-gallate treatment of human skin inhibits ultraviolet radiation-induced oxidative stress. Carcinogenesis, 22(2), 287-294. https://doi.org/10.1093/carcin/22.2.287
Tier 2Controlled human skin study
Direct evidence that topical EGCG reduces UV-induced oxidative stress in human skin. Used a purified EGCG preparation, not a sugar scrub; cited for the antioxidant mechanism.
Chiu, A. E., Chan, J. L., Kern, D. G., Kohler, S., Rehmus, W. E., & Kimball, A. B. (2005). Double-blinded, placebo-controlled trial of green tea extracts in the clinical and histologic appearance of photoaging skin. Dermatologic Surgery, 31(7 Pt 2), 855-860. https://doi.org/10.1111/j.1524-4725.2005.31731
Tier 2Randomised controlled trial
Topical green tea cream improved elastic tissue in photoaged skin on histology, though visible clinical change was modest. Used a 10% green tea cream, a different format and dose to a scrub.
Scapagnini, G., Davinelli, S., Di Renzo, L., De Lorenzo, A., Olarte, H. H., Micali, G., Cicero, A. F., & Gonzalez, S. (2014). Cocoa bioactive compounds: Significance and potential for the maintenance of skin health. Nutrients, 6(8), 3202-3213. https://doi.org/10.3390/nu6083202
Tier 2Peer-reviewed review
Reviews cocoa flavanols (epicatechin, catechin) as skin antioxidants. Much of the human data is oral cocoa intake; cited for the flavanol antioxidant mechanism, not as proof a scrub matches those results.
Evangelista, M. T. P., Abad-Casintahan, F., & Lopez-Villafuerte, L. (2014). The effect of topical virgin coconut oil on SCORAD index, transepidermal water loss, and skin capacitance in mild to moderate pediatric atopic dermatitis. International Journal of Dermatology, 53(1), 100-108. https://doi.org/10.1111/ijd.12339
Tier 2Randomised controlled trial
Topical virgin coconut oil reduced transepidermal water loss and improved skin hydration versus mineral oil (mean SCORAD reduction 68% vs 38%). Population was paediatric atopic dermatitis, not the general body-skin user; cited for the barrier and hydration mechanism.
Tang, S.-C., & Yang, J.-H. (2018). Dual effects of alpha-hydroxy acids on the skin. Molecules, 23(4), 863. https://doi.org/10.3390/molecules23040863
Tier 2Peer-reviewed review
Supports the AHA exfoliation mechanism. Discusses AHAs at formulation strengths above what raw rapadura sugar delivers, so the page applies the mechanism, not the magnitude.