Iron supplements are often a standard recommendation for the treatment of fatigue, particularly among women. A 2012 randomized study confirmed the efficacy of iron in supporting energy balance.
French researchers studied nearly 200 menstruating women ages 18 to 53 who complained of fatigue but were otherwise healthy. All subjects had lower-than-normal ferritin levels (less than 50 mcg per liter). During the study, half of the subjects took 80 mg of iron daily, while the other half took a placebo. Fatigue was measured using a validated questionnaire at the beginning and end of the study.
At the close of 12 weeks, patients receiving the iron pills reported favorable outcomes related to fatigue and energy balance compared to the placebo group. The researchers also found that iron supplements increased the production of red blood cells.