The 4 AA formulation stimulated ⁵⁹Fe absorption in iron-deficient male mice. 2.5 µCi of ⁵⁹Fe in the control (Ctrl) or 4 AA formulation was administered to each mouse by oral, intragastric gavage after a 2-hour fast. One hour later, mice were sacrificed, iron absorption (percent of dose) was calculated (A), and ⁵⁹Fe activity was determined in the blood (B), duodenum (C), and liver (D). Blood was also taken from the tail vein 30 minutes after gavage, and ⁵⁹Fe activity was measured (E). Student’s parametric t tests were performed unless variances were significantly different or normality was not achieved, and in that case, a nonparametric t test was performed. n = 10 per group; *P < .05.