What is the half life of a 1000 mcg folate supplement? in other words, not withstanding existing folate in my body or what i eat, how long for 1000 mcg supplement to be out of my system? thx?

The half life is the term used to describe when 1/2 a drug/material is eliminated from the body. For folic acid the half life is sited as 1.5 to 2 hrs. The general rule is it takes 4 half lives to remove a substance from the body. Some separate compartments like the spinal fluid circulation may retain it longer. I would expect it to be gone in less than a day.

Agree with Dr. Fergusson. Folic acid is cleared quickly from circulation. It does persist longer in tissue, e.g., red cells. It is important to ensure adequate daily intake of folic acid. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Wish you good health