Fig. 1. Time-dependent change in cumulative fractional absorption of magnesium after dosing with ²⁶Mg orally and ²⁵Mg intravenously. Data shown are for the mean ± SD of the total fraction of the cumulative absorption fraction measured after 120 hours at each 8-hour interval up to 120 hours. The total mean absorption fraction at 120 hours was 44% [7]. For example, the first point shows that at 8 hours after completion of ²⁶Mg dosing, the mean fractional absorption was 64% of this 44%. Absorption was 95% complete after 72 hours.