During this double-blind, placebo-controlled, randomized crossover study, participants received 17-day treatments with ascorbic acid (500 mg twice per day) or with placebo. On Day 14, participants’ blood was collected at various intervals for 72 h and plasma ascorbic acid concentrations were measured in each of the samples taken; averages of these concentrations are reported herein. Vitamin C supplementation increased ascorbic acid plasma concentrations (mean ± SD, p <0.0001, n=22), but the concentrations were not different between smokers and nonsmokers, or between men and women. These data have been published previously [26].