Fig. 4. Epidermal thickness of hairless mice treated with PPE. NC: Drinking water intake without UVB irradiation; Con: Drinking water intake with UVB irradiation; PO: 0.1% Hydrolyzed collagen (HACP-U2) intake in drinking water with UVB irradiation; OL: 0.05% PPE intake in drinking water with UVB irradiation; OH: 0.1% PPE intake in drinking water with UVB. Values are mean±SEM (n=6). Means with different letters indicate significant differences at p<0.05.