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 state 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 also recharges vitamin E. 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 less harmful 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, so your cell breaks it down fast and you're left with much less CoQ10-recycling activity. Two A copies leaves only a small fraction of normal enzyme activity. 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) and 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 is somewhat reduced compared to GG. |
| 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. |
Genotypes are shown order-insensitively and on the forward strand; your own export may print the complementary letters — the meaning is the same.
What the research suggests
NQO1 is the enzyme that reduces CoQ10 (ubiquinone) into ubiquinol, the antioxidant form. The rs1800566 A allele (Ser187) is predicted to damage NQO1 activity, so if you carry one or two A copies your body recycles CoQ10 less efficiently. Taking the reduced form directly hands your cells ubiquinol 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, hinting that this variant influences CoQ10 status, though the data is preliminary.
PubMed 21774831 · Fischer et al., BMC Res Notes 2011. Pilot study in 54 healthy men given 150 mg/day reduced-form CoQ10 (ubiquinol) for 14 days. PolyPhen flagged the NQO1 P187S variant as possibly damaging to enzyme activity, and at baseline heterozygous P187S carriers had significantly lower serum CoQ10 than homozygous variant (S/S) carriers (0.93 ± 0.25 vs 1.34 ± 0.42 µM, p = 0.044), suggesting the variant influences human CoQ10 metabolism. Small, single-study evidence.
Educational only — not medical advice. “General evidence” means the finding is real but the supplement’s benefit isn’t unique 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 that carriers run lower than non-carriers. Treat 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 depend on the recycling step that 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). The biology is identical, 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.