Abstract We demonstrate that 0.78 mm glyceric acid activated the proliferation of human dermal fibroblasts by about 45%, whereas 34 mm α-glucosylglyceric acid (GGA) increased collagen synthesis by the fibroblasts by 1.4-fold compared to that in the absence of GGA. The two substances also exerted protective effects on both DNA scission by the hydroxyl radical and protein aggregation by heat in vitro.