In people

The order of recovery is consistent. Energy and the sore tongue lift first, often within one to two weeks, because blood and lining tissue turn over fast. The blood count climbs over four to eight weeks as large pale cells are replaced by normal ones. Nerve symptoms move last and slowest, over months, and how much comes back depends on how long they were starved. Mood and clarity usually improve with the energy, and people describe it as the fog lifting rather than a lift in drive. Blood levels of homocysteine and methylmalonic acid fall as the enzymes start turning over again, which is the measurable version of the same story.