G6PD deficiency: why skip high-dose vitamin C
Megadose vitamin C gets sold as a harmless health habit. Carry a G6PD variant and it isn't.
G6PD is the enzyme that shields your red blood cells from oxidative stress. Run short of it and that shield fails, so strong oxidants can make red cells burst apart. Doctors call that hemolysis. The gene sits on the X chromosome, which is why men take the hardest hit. High-dose vitamin C is one of the most common triggers. It's also one of the easiest to avoid.
You carry a G6PD-deficiency variant. With this variant, high-dose vitamin C and other strong oxidants can make your red blood cells break apart, which is called hemolysis. Keep vitamin C to normal food and RDA amounts. This hits men hardest, since they only have one X copy and no second gene to fall back on. Treat it as a flag to act on, not a diagnosis. A doctor can confirm your G6PD status with a simple blood test.
PubMed 38898838 · G6PD deficiency & vitamin C hemolysis
You carry the G6PD Mediterranean variant, which is one of the more severe forms of the deficiency. High-dose vitamin C and other strong oxidants can break your red blood cells apart, and so can fava beans and certain drugs. Keep vitamin C to normal food amounts. This hits men hardest, since they only have one X copy and no second gene to fall back on. Treat it as a flag to act on, not a diagnosis. A doctor can confirm your G6PD status with a simple blood test.
PubMed 38898838 · G6PD deficiency & vitamin C hemolysis
What G6PD does
The rule is short. Keep vitamin C to food and RDA levels. Fava beans and a handful of drugs are the other classic triggers in G6PD deficiency, so they're worth knowing too.
This is a heads-up, not a diagnosis. A simple blood test tells a doctor where you actually stand. It matters most for men, who carry one copy of the X chromosome and have no backup.
Your variants, decoded
One of the most common deficiency variants, seen mostly in people of African ancestry.
| CC | Typical. No deficiency variant here. |
| CT | One copy. In women (two X chromosomes) this is carrier-level — play it safe with strong oxidants. In men (one X), a single variant copy means full deficiency — treat it as deficient. |
| TT | Deficiency variant present (both copies — or a single copy in men). Skip high-dose oxidants. |
A harsher form of the deficiency than the A- variant.
| GG | Typical. No deficiency variant here. |
| GA | One copy of the Mediterranean variant. Carrier-level in women; in men (one X), a single copy means full Mediterranean deficiency — strict avoidance. |
| AA | Mediterranean deficiency (both copies, or a single copy in men). Tighter avoidance than the milder forms. |
We show genotypes on the forward strand and ignore letter order. Your own export may print the complementary letters. Same result either way.
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Questions
Can I take vitamin C with G6PD deficiency?
Normal amounts from food are usually fine. The trouble starts with high-dose or IV vitamin C, and other strong oxidants, which can set off hemolysis. Check your status with a clinician before you assume anything.