Coenzyme Q10

Coenzyme Q10 — sold as CoQ10, and listed in chemical databases as ubidecarenone or ubiquinone-10 — is a compound naturally present in the human body. NCCIH states that its highest levels are in the heart, liver, kidneys and pancreas, and that it is sold in the United States as a dietary supplement. Most of the questions people bring to it concern the heart, and that is also where the cited evidence is weakest.

What is CoQ10?

NCCIH describes coenzyme Q10 as a substance naturally present in the human body, concentrated in the heart, liver, kidneys and pancreas. PubChem lists it under CID 5281915 with the molecular formula C59H90O4 and a molecular weight of 863.3, and records ubidecarenone, ubiquinone-10 and CoQ10 among its names, with CAS number 303-98-0.

Supplement labels use two related names. Ubiquinone is the oxidised form and the one the PubChem record above describes; ubiquinol is its reduced form. Products are sold as both. NCCIH’s page does not compare the two, so this entry does not either.

What does CoQ10 do?

The honest answer from the cited source is narrower than the marketing around it. NCCIH describes where CoQ10 sits in the body — highest in the heart, liver, kidneys and pancreas — and describes it as sold as a dietary supplement. The page does not set out a single function that supplemental CoQ10 performs, and it does not state an amount to take.

Where NCCIH does comment, it is mostly to report that the research has not settled. That is covered question by question below.

What is CoQ10 good for?

NCCIH’s summaries by condition:

• Heart disease and heart failure. Only a few studies have looked at whether CoQ10 might reduce the risk of heart disease, and NCCIH calls their results inconclusive. It describes the research on CoQ10 in heart failure as also inconclusive. It notes evidence suggesting CoQ10 may reduce some complications of heart surgery.
• Statin-related muscle pain. NCCIH states that the overall scientific evidence does not support the idea that CoQ10 can reduce muscle pain associated with statins.
• Blood pressure. The small amount of evidence available suggests CoQ10 probably does not have a meaningful effect on blood pressure.
• Parkinson’s disease. CoQ10 did not improve symptoms in patients with early Parkinson’s disease, and NCCIH cites a 2017 evaluation concluding it is not helpful for Parkinson’s symptoms.
• Cancer. NCCIH states CoQ10 has not been shown to be of value in cancer care, while noting it may reduce the risk of heart damage caused by certain chemotherapy drugs.
• Other conditions. CoQ10 has been studied in ALS, Down syndrome, Huntington’s disease and male infertility, and NCCIH describes that research as too limited for any conclusions.

Nothing on that list is an endorsement, and several entries are explicitly negative findings. This page reports the state of the cited record; it is not advice about what anyone should take.

What medications should not be taken with CoQ10?

NCCIH names three interactions:

• Warfarin, the anticoagulant. NCCIH lists CoQ10 as a supplement that may interact with it.
• Insulin, the diabetes drug.
• Some types of cancer therapy, which NCCIH describes CoQ10 as possibly not compatible with.

Two things are worth stating precisely, because pages on this question often go further than the source does.

First, blood-pressure medication is widely listed elsewhere as a CoQ10 interaction on the reasoning that CoQ10 lowers blood pressure. NCCIH’s own assessment is that CoQ10 probably does not have a meaningful effect on blood pressure. NCCIH does not name antihypertensives among the drugs CoQ10 may interact with.

Second, NCCIH’s wording is “may interact,” not a demonstrated interaction with a measured size. It names the drugs; it does not quantify the effect.

Anyone taking warfarin, insulin or cancer therapy has a clear reason to raise CoQ10 with the clinician managing that medication. That is a conversation with a prescriber, not something a reference page can settle.

Does CoQ10 have side effects?

NCCIH reports that no serious side effects of CoQ10 have been reported, and that mild side effects such as insomnia or digestive upset may occur.

The page gives no upper limit and no recommended amount, and it does not discuss use in pregnancy or in children. Absence from the page is not a safety finding in either direction — it means this source does not address it.

Currency of this entry

The NCCIH page this entry rests on carries a last-updated date of January 2019. That matters for a compound with an active research literature: work published since then is not reflected in the source, and therefore is not reflected here. Where a newer authoritative summary exists, this entry should be revised against it.