NQO1: The Enzyme That Keeps Your CoQ10 in Fighting Shape
The recycler behind your CoQ10's antioxidant punch.
NQO1 is the enzyme that keeps your coenzyme Q10 in the form that actually fights free radicals. CoQ10 sits in your cell membranes in two states. One is built for making energy. The other, ubiquinol, is the antioxidant version that shields your fats and membranes from oxidative damage. NQO1's job is to flip CoQ10 back into that protective form so it can keep working, over and over. The same enzyme recharges vitamin E too. A single common change in this gene quietly weakens the whole operation, and that's what this page is about. Educational only, not a diagnosis.
What NQO1 does
Reduces coenzyme Q10 (ubiquinone) into ubiquinol, the form that works as a fat-soluble antioxidant in your membranes.
Keeps CoQ10 cycling between its energy form and its antioxidant form so a small pool of it can protect a lot of membrane.
Does the same recycling trick for vitamin E, regenerating its antioxidant form after it neutralizes a free radical.
Detoxifies reactive quinone compounds by reducing them to gentler versions, part of your cell's built-in defense against oxidative stress.
Your variants, decoded
The G allele builds proline at position 187 and gives you a fully working enzyme. The A allele swaps in serine, and that version of the protein is unstable. Your cell breaks it down fast, leaving much less CoQ10-recycling activity. Two A copies leaves only a small fraction of normal enzyme activity. One note: a 23andMe export reads the other DNA strand, so it may print these as C and T instead of G and A. C lines up with G (the working version), T lines up with A (the variant).
| GG | Two working copies. Your NQO1 recycles CoQ10 and vitamin E at full speed. The typical, higher-activity result. |
| GA | One working copy, one variant copy. Activity sits in the middle, so recycling runs lower than GG but holds up better than AA. |
| AA | Two variant copies. The serine version of the enzyme gets degraded quickly, leaving only a small fraction of normal activity. The lowest CoQ10-recycling capacity of the three. |
We show genotypes on the forward strand and ignore letter order. Your own export may print the complementary letters. Same result either way.
What the research suggests
NQO1 is the enzyme that reduces CoQ10 (ubiquinone) into ubiquinol, the antioxidant form. The rs1800566 A allele (Ser187) destabilizes the enzyme, so the mutant protein is rapidly degraded and carrying one or two A copies means your body recycles CoQ10 less efficiently. Taking the reduced form hands your cells ubiquinol directly, without relying on the recycling step your enzyme is poor at. A small human study using the reduced form found a baseline CoQ10 difference between NQO1 genotype groups, a hint that this variant influences CoQ10 status. The data is preliminary.
PubMed 11160862 · Siegel et al., Mol Pharmacol 2001. The NQO1*2 (Pro187Ser) protein is rapidly polyubiquitinated and degraded by the proteasome (completely cleared within about two hours, while wild-type NQO1 is not), and cells homozygous for NQO1*2 are deficient in NQO1 activity. This is the mechanism behind the unstable serine-187 enzyme and its reduced CoQ10-recycling capacity. (Direct human CoQ10-status data remain preliminary: a 54-man pilot, PubMed 21774831, found a baseline difference between genotype groups but did not cleanly show carriers run lower.)
Educational only, not medical advice. “General evidence” means the finding is real, but the benefit isn’t specific to your genotype.
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Questions
Does the NQO1 variant mean I'm low on CoQ10?
Not necessarily. The variant lowers how efficiently your enzyme recycles CoQ10 into its antioxidant form, not how much CoQ10 you eat or make. The human evidence here is thin: one small study of 54 men found a difference in baseline CoQ10 between genotype groups, but it didn't cleanly show carriers run lower than non-carriers. Take it as a reason to favor the reduced form, not proof you're deficient.
Ubiquinol or regular CoQ10 if I have the A allele?
Ubiquinol is the logical pick. It's already in the reduced, antioxidant form, so it doesn't lean on the recycling step your NQO1 enzyme is slow at. Plain ubiquinone CoQ10 still works for plenty of people. But if your enzyme is sluggish, ubiquinol skips the bottleneck.
Will a 23andMe file show G/A or C/T?
It may show C/T. Your DNA has two strands, and labs sometimes report the opposite one. For rs1800566, C matches G (the working, proline version) and T matches A (the variant, serine version). Same biology, just read from the other strand.
Is this a safety or medication issue?
CoQ10 itself is well tolerated, so this isn't a pharmacogenomic gene in the dangerous sense. But CoQ10 levels drop with statin use and matter in heart health. So if you take medication or have a heart condition, talk to your doctor or pharmacist before starting a supplement. Don't self-adjust any medication based on this.