Steady-state plasma vitamin C concentrations from consuming 5-9 servings of vitamin C-rich fruits and vegetables daily are around 80 micromoles per liter or less.

“remember 200 micrograms has been shown to raise plasma levels to 90 micro moles per liter which might make a difference in someone with very low vitamin C levels but perhaps not so much in someone that already has a steady state level of 70 to 80 micro moles per liter”

“There are three important things to take home from that statement first there is a maximum plasma concentration of vitamin C achieved orally which is 220 micro moles per liter of blood second three grams of oral vitamin C taken six times per day can sustain maximum plasma levels whereas a single three gram dose cannot third the maximum plasma vitamin C concentration from intravenous vitamin C can be as high as 15,000 micro moles per liter which is 68 times higher than can be achieved through oral consumption”

“200 milligrams of oral vitamin C produces plasma levels of about 90 micro moles per liter not much of an increase over baseline levels”