Ubiquinone and ubiquinol are the same molecule — Coenzyme Q10 — in two different states. Ubiquinone is the oxidized form. Ubiquinol is the reduced form. Your body converts between them constantly, shuttling electrons back and forth in the mitochondrial electron transport chain. The practical difference is this: ubiquinol gets into your bloodstream faster on a per-milligram basis. Ubiquinone has the longer track record of clinical evidence for hard outcomes — the kind that matter more than a blood test number. Neither is a clear winner across every situation, and the price gap between them doesn't reflect the evidence gap.
You're staring at two bottles. One says CoQ10 — 100 mg, $20. The other says Ubiquinol — 100 mg, $45. The internet has told you, loudly and repeatedly, that ubiquinol is "better absorbed" and "up to 8x more bioavailable" and "the active form your body actually uses." The ubiquinol bottle has a shiny gold label. The ubiquinone bottle looks like it's been on the shelf since 2005. And you're standing there wondering: is this a meaningful upgrade, or did I just get upsold by a better marketing department?
Here is the answer in one sentence: ubiquinol does absorb more efficiently in head-to-head pharmacokinetic studies, but ubiquinone has more clinical-outcome data — including reductions in cardiovascular mortality that ubiquinol studies haven't replicated — and the absorption gap largely disappears when ubiquinone is taken with a meal that contains some fat.
The redox cycle: your body is already doing the conversion
CoQ10 exists in every cell membrane and every mitochondrion in your body. Its fundamental job is electron transport — accepting electrons from Complex I and Complex II in the respiratory chain, then passing them to Complex III. This requires the molecule to cycle between oxidized (ubiquinone) and reduced (ubiquinol) states roughly 100 times per second in a working mitochondrion.
When you swallow a ubiquinone capsule, your body reduces it to ubiquinol in the intestinal wall and liver before it enters circulation. When you swallow ubiquinol directly, it arrives pre-reduced and can enter the bloodstream in that form. The body interconverts them so efficiently that after about 24 hours, the ratio of ubiquinol to total CoQ10 in your plasma is virtually identical regardless of which form you took. The question is how much total CoQ10 gets into your blood in the first place — and that's where the two forms diverge.
What the bioavailability studies actually found
The best head-to-head comparison comes from Langsjoen and colleagues (2014). Twelve healthy volunteers took 200 mg per day of each form for four weeks, with a four-week washout between. Ubiquinone raised total plasma CoQ10 from 0.9 to 2.5 µg/mL. Ubiquinol raised it from 0.9 to 4.3 µg/mL. Both increases were significant — but ubiquinol's was larger, and the difference was statistically significant (P < 0.005). On raw pharmacokinetics, ubiquinol wins.
Zhang and colleagues (2018) ran a similar study in older men — the population most often targeted by ubiquinol marketing, since CoQ10 synthesis declines with age. After two weeks at 200 mg per day, ubiquinol significantly increased plasma total CoQ10 1.5-fold. Ubiquinone did not produce a statistically significant increase in this population. Six of ten subjects responded better to ubiquinol, two to ubiquinone. This is the study ubiquinol marketers cite most.
But here is the part they leave out: neither form changed any measured biomarker of oxidative stress in the Zhang study. Not FRAP, not total thiol, not malondialdehyde. Both forms got CoQ10 into the blood, and neither form produced a measurable improvement in the oxidative-stress endpoints the researchers were tracking. The biomarker didn't move. That does not mean CoQ10 does nothing — it means the story is more complicated than "higher blood levels = better outcomes."
The evidence that complicates the bioavailability story
If bioavailability were the only variable that mattered, ubiquinol would be the unambiguous winner and this article would end here. But in 2023, Fladerer and Grollitsch published a review of 28 clinical trials comparing the two forms — and the results upend the simple "ubiquinol is better" narrative.
Their key findings: CoQ10 supplementation reduced cardiovascular death — this outcome was not reported for ubiquinol. The doses of ubiquinone that produced cardiovascular benefits were substantially lower than the doses used in ubiquinol trials. And long-term reductions in cardiovascular mortality were observed only in the ubiquinone studies. The authors' conclusion was direct: they recommend ubiquinone, not ubiquinol, for cardiovascular disease prevention.
This does not mean ubiquinone is "better" in some absolute sense. It means that more blood CoQ10 — which ubiquinol clearly delivers — does not necessarily translate to better long-term outcomes in the studies we have. Ubiquinone has been studied for decades. Ubiquinol is newer to market. The evidence base is larger, deeper, and longer for ubiquinone — and that matters if you're making decisions based on outcomes rather than pharmacokinetic curves.
Why fat changes the absorption math
CoQ10 is fat-soluble. It dissolves in lipids, not water. Take it on an empty stomach with a glass of water and you'll absorb very little of either form. Take it with a meal that contains some fat — eggs, avocado, olive oil, salmon — and absorption increases substantially for both.
Mantle and Dybring (2020) reviewed the absorption mechanisms and found that co-administration with dietary fat is one of the most significant variables in CoQ10 bioavailability — potentially larger than the ubiquinone-vs-ubiquinol distinction itself. Pravst and colleagues (2020) tested different ubiquinone formulations in older adults and found that fat-solubilized ubiquinone could achieve bioavailability comparable to ubiquinol. The formulation technology — how the CoQ10 is dissolved in oil inside the softgel — matters at least as much as whether it starts as ubiquinone or ubiquinol.
This is why the softgel matters. A well-formulated ubiquinone softgel, suspended in oil and taken with food, narrows the absorption gap against ubiquinol to the point where the price difference becomes the more important variable.
What to do with this information
1. Take CoQ10 with food. This is the single biggest lever for either form. A meal with 5-10 grams of fat is enough. Your morning eggs, a handful of almonds, or a spoonful of olive oil on your salad — any of these will multiply absorption.
2. If you're over 40 or on a statin, the absorption question matters more. CoQ10 synthesis declines with age, and statins reduce endogenous CoQ10 production by inhibiting the same pathway. In these scenarios, the ubiquinol absorption advantage is more relevant — though the same fat-with-food rule applies.
3. Don't pay a premium for ubiquinol unless you've tried ubiquinone first. If you take ubiquinone with food and notice a difference in how you feel, the extra cost of ubiquinol may not add much. If you take it for months with no effect, switching forms is worth a trial — but start with the less expensive option.
4. Look at the formulation, not just the form. A ubiquinone softgel in an oil base, taken with food, may outperform a cheap ubiquinol powder in a dry capsule. The delivery system matters.
FAQ
What is the difference between ubiquinone and ubiquinol?
They are the same molecule — Coenzyme Q10 — in two different oxidation states. Ubiquinone is the oxidized form (CoQ10); ubiquinol is the reduced form (CoQH2). Your body converts between them constantly. Ubiquinone must be reduced to ubiquinol in the body to function as an antioxidant, which healthy people do efficiently.
Is ubiquinol better than CoQ10 ubiquinone?
Ubiquinol is better absorbed on a per-milligram basis, as shown in multiple pharmacokinetic studies. However, ubiquinone has a larger body of long-term clinical-outcome evidence — particularly for cardiovascular endpoints — and the absorption gap narrows substantially when ubiquinone is taken with a fatty meal. The label "better" depends on what you're optimizing for: blood levels or clinical outcomes.
Which is better absorbed — ubiquinone or ubiquinol?
Ubiquinol is better absorbed in head-to-head studies. Langsjoen et al. (2014) found ubiquinol raised plasma CoQ10 to 4.3 µg/mL versus 2.5 µg/mL for ubiquinone at the same dose. However, taking ubiquinone with dietary fat and in an oil-based softgel formulation significantly narrows this gap.
Does CoQ10 ubiquinone convert to ubiquinol in the body?
Yes. Healthy humans efficiently reduce ubiquinone to ubiquinol in the intestinal wall and liver. After about 24 hours, plasma ratios of ubiquinol to total CoQ10 are similar regardless of which form was ingested. The conversion efficiency does decline with age — one reason ubiquinol may offer more advantage for older adults.
Should I take ubiquinol or regular CoQ10 if I take a statin?
Statins reduce endogenous CoQ10 production by inhibiting HMG-CoA reductase, the same enzyme that produces cholesterol. Supplementation can help maintain CoQ10 levels. Both forms are effective when taken with food, but if you've tried ubiquinone and noticed no benefit after consistent use, ubiquinol is a reasonable next step. Discuss with your healthcare provider — CoQ10 supplementation while on statins is a conversation to have with the person who prescribed them.
References
- Langsjoen PH, Langsjoen AM. Comparison study of plasma coenzyme Q10 levels in healthy subjects supplemented with ubiquinol versus ubiquinone. Clinical Pharmacology in Drug Development. 2014. PMID: 27128225.
- Zhang Y, Liu J, Chen XQ, Oliver Chen CY. Ubiquinol is superior to ubiquinone to enhance Coenzyme Q10 status in older men. Food & Function. 2018. PMID: 30302465.
- Fladerer JP, Grollitsch S. Comparison of Coenzyme Q10 (Ubiquinone) and Reduced Coenzyme Q10 (Ubiquinol) as Supplement to Prevent Cardiovascular Disease and Reduce Cardiovascular Mortality. Current Cardiology Reports. 2023. PMID: 37971634.
- Mantle D, Dybring A. Bioavailability of Coenzyme Q10: An Overview of the Absorption Process and Subsequent Metabolism. Antioxidants. 2020. PMCID: PMC7278738.
- Pravst I, Rodriguez Aguirre MA, Zmitek K, et al. Comparative Bioavailability of Different Coenzyme Q10 Formulations in Healthy Elderly Individuals. Nutrients. 2020. PMID: 32188111.
Disclaimer: This article is for educational purposes. It does not constitute medical advice. The statements made about dietary supplements have not been evaluated by the Food and Drug Administration. Monthlees products are not intended to diagnose, treat, cure, or prevent any disease. Speak with a qualified healthcare professional before starting any supplement regimen. Individual results vary; no outcome is guaranteed.
