In the 10 minutes it takes to donate a unit of blood, your body will need 24 weeks to replace the iron you lose if you aren’t on a supplement. Many donors have healthy hemoglobin levels, but low in iron. A study published in JAMA looked at the effects of taking a low-dose iron supplement, finding that it was indeed effective in shortening the time needed to recover hemoglobin and iron levels for both individuals who were iron deficient, and those who were considered to have healthy iron levels.
