vitamin · for chronic fatigue
Vitamin C
Your body needs vitamin C to make carnitine, which is involved in producing energy.
Say that in clinical terms
Vitamin C is required for carnitine and catecholamine synthesis, both implicated in energy metabolism, which is the basis for a proposed anti-fatigue effect.
How strong is the research?
Not verified evidence
2 papers read.
Tested as: 1000 mg/day oral vitamin C for 4 weeks in adults with low (not deficient) vitamin C status, versus a single 10 g intravenous dose in healthy office workers — neither reflects typical over-the-counter oral use in vitamin-C-replete adults
We read the research behind this and none of it concluded that it works for this. That is a finding about the papers, not a verdict that it does nothing.
How much to take
1000–10000 mg
Before you take it
- NIH ODS Tolerable Upper Intake Level (UL) for adults is 2,000 mg/day (combined dietary and supplemental intake)
- GI distress (osmotic diarrhea, nausea, abdominal cramping) commonly occurs above 1,000 mg/day due to unabsorbed ascorbic acid reaching the colon
- Sustained high-dose supplementation increases risk of calcium oxalate kidney stones; particular caution warranted in individuals with prior nephrolithiasis or hyperoxaluria
- Vitamin C markedly enhances non-heme iron absorption; supplemental doses are contraindicated in hemochromatosis and other iron-overload conditions
- High-dose Vitamin C antioxidant activity may attenuate the efficacy of chemotherapy and radiation therapy; per NIH ODS, consultation with an oncologist is required before supplementing during active cancer treatment
- High-dose Vitamin C combined with antioxidant mixtures (including vitamin E, beta-carotene, selenium) may blunt the HDL-raising effect of niacin-statin combination therapy per NIH ODS