This study reviews the results of a three-arm, parallel-group, randomized, double-blind, placebo-controled weekly iron and folic acid supplementation efficacy trial among Malaysian women aged 18–45 years, who were randomly assigned to three treatment groups—60 mg Fe as ferrous fumarate and either 0 mg, 0.4 mg, or 2.8 mg of folic acid, to be consumed once weekly for 16 weeks, followed by a four-week washout period. The article presents evidence to inform the World Health Organization (WHO) weekly iron and folic acid supplementation guidelines, and advocates for this formulation to be included in the WHO Model Essential Medicines List.