Guide

Coenzyme Q10 and the heart: what is known?

There is a large volume of research on coenzyme Q10 and the results are inconsistent. There is also no authorised health claim in the EU. Both facts belong in the same sentence.

Short answer: There is no authorised health claim for coenzyme Q10 in the EU register — the claims assessed, covering energy metabolism, blood pressure, protection from oxidative damage, cognitive function, blood cholesterol and endurance, did not become authorised claims. There is research on heart failure and on statin-associated muscle symptoms; the findings are mixed and not settled.

What coenzyme Q10 is

A compound involved in the mitochondria, the energy-producing centres of the cell, and also produced by the body. Its two forms, ubiquinone and ubiquinol, have their own practical considerations around absorption — all covered in What is coenzyme Q10?. This page focuses on the cardiovascular heading only.

Claim status — the clear part

EFSA assessed a range of coenzyme Q10 claims under Article 13(1) of Regulation (EC) No 1924/2006. The headings assessed were energy-yielding metabolism, blood pressure, protection of DNA, proteins and lipids from oxidative damage, cognitive function, blood cholesterol and endurance capacity.

As of today none of these is an authorised claim usable on a label. So a statement such as “coenzyme Q10 protects the heart” or “gives you energy” may not legally be used. What follows on this page is research, not claims.

Heart failure research

A 2013 meta-analysis of randomised trials suggested coenzyme Q10 may improve functional status in patients with heart failure.
The Q-SYMBIO trial, a randomised study of 3 × 100 mg daily over two years, pointed to a possible adjunctive role in heart failure.
Clinical reference sources assessing the same area are more cautious: some preliminary studies suggest it may be useful, but results are unclear and more evidence is needed.

Important: these studies were conducted in patients with diagnosed heart failure, under medical supervision and in addition to drug therapy. Heart failure is not a supplement matter, and these findings are not a rationale for preventive use in healthy people.

Muscle symptoms in people taking statins

This is one of the most common questions about Q10. The evidence is mixed:

A 2018 meta-analysis (12 randomised trials, 575 patients) reported significant reductions in muscle pain, weakness, cramp and tiredness compared with placebo. The same analysis was considered limited because of heterogeneity between the included studies.
Individual trials conflict: a 2014 randomised trial reported a reduction in mild to moderate muscle symptoms, while a 2015 study found no improvement in statin-associated myalgia.
A cardiologist’s review notes that trial results conflict but that the overall direction seen in meta-analyses supports use.

The practical point: if you develop muscle pain while taking a statin, that is a situation that may call for a change of dose or drug, and it must be reported to your doctor. Do not stop statin therapy on your own and do not substitute a supplement for it.

When to see a doctor

Chest pain, breathlessness, palpitations, swelling in the legs or a drop in exercise capacity should be assessed without delay. If you take cardiac medication — particularly blood thinners — consult your doctor before starting any new supplement.

Frequently asked

The questions most often searched on this topic, answered as they are.

When should coenzyme Q10 be taken?

As a fat-soluble compound, it is commonly suggested to take it with a meal containing fat. In one study, Q10 dissolved in an oil matrix raised blood levels more than the same amount in crystalline form. The same study reported that splitting the daily amount improved the serum response.

Ubiquinol or ubiquinone?

Ubiquinone is the classic form and is converted to ubiquinol in the body; ubiquinol is the ready-to-use form. Better absorption is claimed for ubiquinol, but the difference is not independently settled for every age group. See What is coenzyme Q10?.

I take a statin. Should I take Q10?

Leave that decision to your doctor. A meta-analysis of 12 randomised trials reported reductions in muscle pain, weakness, cramp and tiredness, but it was considered limited because of heterogeneity, and individual trials conflict. Do not stop statin therapy on your own and do not substitute a supplement for it.

Does coenzyme Q10 have side effects?

In a safety study in healthy adults testing 300, 600 and 900 mg/day over four weeks, no serious adverse events were observed; the effects reported were mild gastrointestinal complaints such as abdominal pain and soft stools, and were not dose-related.

I take a blood thinner. Is there a problem?

If you take cardiac medication — particularly a blood thinner — consult your doctor before starting any new supplement. This applies to Q10 and to magnesium alike.

Is there an authorised health claim for Q10?

No. EFSA assessed energy metabolism, blood pressure, protection from oxidative damage, cognitive function, blood cholesterol and endurance, and none of these became an authorised claim usable on a label. What appears on this page is research, not claims.