Depends. There are many different kinds of anemia, each of which have their own causes. You need to figure out what kind of anemia you have and what needs to be done to treat it. It could be that a simply nutritional supplement (iron, b12, thiamine) will be enough. It could be a more chronic problem that has no quick fix. If you're anemic for any reason, you need to see your doc right away.
Agree it depends. There is anemia from blood loss (iron deficiency), poor nutrition, chronic illness, and then there are some genetic anemias like sickle cell or thalassemia where one will be anemic always...Mildly. It is helpful to see your doc and have the blood work and evaluation that determines what kind you have.Simple iron deficiency anemia usually takes 3-6 months to fully correct .