The fastest way to raise ferritin depends on how severe the deficiency is and what is causing it. In mild to moderate deficiency, oral iron therapy and iron-rich nutrition may be effective, but improvement usually takes weeks to months. In more severe cases, in people who do not respond to oral treatment, or in those with malabsorption, intravenous iron may produce a faster rise. However, focusing only on raising the ferritin number quickly is not enough. If the underlying cause—such as heavy menstrual bleeding, gastrointestinal blood loss, celiac disease, pregnancy, or chronic inflammation—is not addressed, ferritin may drop again. Vitamin C may help support iron absorption, while excessive tea or coffee, especially around meals, can reduce it. The fastest improvement comes from the right diagnosis and the right treatment strategy working together.