CoQ10 benefits: ubiquinol vs ubiquinone, statins, heart failure and doses used in studies

What CoQ10 is and what it does

Coenzyme Q10 (CoQ10) is a fat-soluble compound found in almost every cell. Mitochondria, the cell’s power stations, need it to produce energy, and it also works as an antioxidant. Your body makes CoQ10 itself, so there’s no recommended daily intake.

So CoQ10 isn’t a vitamin you can run short of through diet. It has been studied for a handful of specific situations, and the evidence varies a lot in quality between them.

People usually buy CoQ10 because:

• They take a statin and have aching muscles.
• They have heart failure and want to discuss extra options with their cardiologist.
• They want “more energy” in midlife, which is exactly where the evidence is thinnest.

Ubiquinol vs ubiquinone: which form is better?

In the body, CoQ10 constantly switches between two forms. Ubiquinone is the oxidised form; ubiquinol is the reduced form. iHerb sells both, and ubiquinol is usually noticeably more expensive.

Labels often call ubiquinol the “active form”, but that’s debatable. A 2020 review of CoQ10 absorption points out that much of the ubiquinol you swallow is oxidised to ubiquinone in the stomach, and the two forms interconvert in the body anyway. In at least one comparison, a well-dissolved ubiquinone was absorbed better than ubiquinol; other studies found the opposite. The fair conclusion: ubiquinol’s advantage isn’t proven.

What does affect absorption is the format. CoQ10 barely dissolves in water, so choose oil-based softgels over dry tablets and take them with a meal.

CoQ10 in oil-based softgels are a sensible choice for most people. Pick ubiquinol only if you’re happy to pay more without a proven benefit.

CoQ10 and statins

Statins lower cholesterol by blocking an enzyme that the body uses to make both cholesterol and CoQ10. That led to the idea that statin muscle pain comes from low CoQ10.

Testing that idea has given mixed results:

• A 2018 meta-analysis (12 trials, 575 people): those taking CoQ10 had less muscle pain, weakness, cramps and tiredness. Creatine kinase, a marker of muscle damage, didn’t change. Doses ranged from 100 to 600 mg a day.
• A 2015 meta-analysis (6 trials, 302 people): no significant effect on pain or creatine kinase.
• NCCIH, the US federal agency for research on complementary health approaches, concludes that overall the evidence doesn’t support CoQ10 for statin muscle pain.

If your muscles ache on a statin, tell the GP who prescribed it. A different statin or a lower dose sometimes helps. You can raise a trial of CoQ10 at the same appointment, but never stop a statin on your own.

CoQ10 for heart failure

This is where the strongest trials are, and where the stakes are highest. CoQ10 is only considered as an add-on to treatment your cardiologist has prescribed.

• Q-SYMBIO (2014): 420 people with moderate to severe chronic heart failure took 100 mg of CoQ10 three times a day or a placebo for 2 years, alongside standard treatment. Major cardiovascular events occurred in about 15% of the CoQ10 group and 26% of the placebo group.
• Cochrane review (2021): 11 trials, 1,573 participants. CoQ10 probably reduces deaths from any cause and hospital admissions for heart failure, with moderate certainty. But the finding on deaths rests on a single trial, Q-SYMBIO, and most other trials were small. The authors say there’s still no convincing evidence for or against it.

If you have heart failure, don’t start CoQ10 yourself. Ask your cardiologist whether it fits your treatment plan.

CoQ10 for blood pressure and energy

CoQ10 is often bought “for circulation” or “for energy”. These are the areas with the least evidence:

• Blood pressure. NCCIH says the limited evidence suggests CoQ10 probably doesn’t have a meaningful effect on blood pressure. It doesn’t replace blood pressure medicines.
• Energy and stamina. The MSD Manual lists popular claims, from exercise performance to skin, fertility and migraines, and notes the studies are not conclusive.
• A 2017 analysis of 14 trials reported better exercise capacity with CoQ10. The participants had heart failure, though, not healthy adults, and the 2021 Cochrane review rated this evidence very uncertain.

If you’re always tired, start by checking the usual causes: iron, vitamin B12, thyroid and sleep.

How much CoQ10 to take

There’s no single recommended dose. These are the amounts used in research:

• Take it with a meal that contains some fat: eggs on toast rather than a plain bowl of porridge.
• Split 200–300 mg into 2–3 doses through the day.
• Trials measured outcomes over weeks and months, not days.
• If it keeps you awake, move it to the morning; insomnia is one of the reported side effects.

CoQ10 is sometimes combined with omega-3 or magnesium. If you take several supplements, start them one at a time so you can tell which one helps or causes side effects.

CoQ10 side effects and who should check first

No serious side effects of CoQ10 have been reported. Nausea, heartburn, stomach pain, diarrhoea, headache, rash and insomnia can occur.

Take extra care if you’re on:

• Warfarin. CoQ10 may make it less effective and raise the risk of clots. Only with your doctor’s agreement and INR monitoring.
• Insulin or other diabetes medicines. CoQ10 may affect blood sugar; you’ll need to monitor it.
• Blood pressure medicines. Interactions have been described; discuss it with your GP.
• Chemotherapy. CoQ10 may not be compatible with some cancer treatments.
• Pregnancy and breastfeeding. Safety hasn’t been established, so don’t take it without medical advice.

Children should only take CoQ10 if a doctor prescribes it. If you take several medicines, check combinations in our vitamin compatibility chart and ask a pharmacist.

How to choose CoQ10 on iHerb

1. Decide whether you need it: on statins, warfarin or with heart failure, talk to your doctor first.
2. Pick the form: ubiquinone in oil-based softgels as the default; ubiquinol if you don’t mind paying more.
3. Check the Supplement Facts panel for CoQ10 per softgel and per serving: 100 mg per softgel is easy to dose.
4. Compare price per 100 mg, not per bottle.
5. Prefer products with independent quality testing (USP, NSF and similar seals).

Our guide to reading a supplement label explains the panel in detail. Other heart and energy supplements are covered in our energy and heart section.