Korean researchers studied 141 healthy office workers aged 20 to 49 who didn't have any diseases — but who were fatigued. Addressing them with IV vitamin C helped restore their energy.
The researchers divided the workers into two groups. One group received an intravenous therapy of 10 grams of vitamin C and the other didn't. Two hours later, the folks getting C felt a lot more energetic, and they also were less fatigued the next day. The non-C group didn't notice any difference. The people who got the most benefit from vitamin C were those who had the lowest blood levels of vitamin C before the therapy.
"Intravenous vitamin C may be a safe and effective treatment for fatigue," the researchers concluded in Nutrition Journal.
I would add that vitamin C is a safe and effective therapy — it's one of the standard IV nutrients given to patients at the Fibro and Fatigue Centers.
Suh SY, Bae WK, et al, Nutrition Journal, 2012 Jan 20; 11(1):7.