Guide
How much CoQ10 is too much?
What the safety literature says about high doses of CoQ10, where 200, 300 and 400 mg sit, and what is missing.
No dose of CoQ10 has been shown to be toxic. A 2006 safety review covering 60 to 1,200 mg a day of ubiquinone found no dose-related stomach complaints and set an observed safe level of 1,200 mg a day; it said data above that were not enough for confidence. An industry trade body wrote it. Our label says not to exceed the recommended dose.
What the safety sources say
The 2006 risk assessment, by the Council for Responsible Nutrition, reviewed the published ubiquinone trials. Nausea and other gastrointestinal complaints were no more common at 1,200 mg a day than at 60 mg, so they could not be linked to dose. It set an observed safe level of 1,200 mg a day and noted that higher doses had been tested without adverse effects, though it judged the data too limited to be confident (Hathcock 2006).
A 4-week study of a branded ubiquinol at 90, 150 and 300 mg a day in healthy volunteers found no clinically relevant changes in lab tests, vital signs or ECG; the product's manufacturer ran it (Hosoe 2007). A 2022 meta-analysis of 13 randomised trials in 1,126 people reported a single gastrointestinal adverse event among the 602 given CoQ10 (Tsai 2022).
What is missing: a long-term study at the top of the range, any study of our capsule, and anything that says an individual can't react. "No dose-related effects in groups" is not "safe for everyone".
Where common doses sit
| Amount a day | Where it sits against the sources |
|---|---|
| 100 mg | Inside the 60 to 1,200 mg reviewed; used for 4 weeks in a small warfarin trial (Engelsen 2003) |
| 200 mg | Our capsule; one-sixth of the 1,200 mg observed safe level |
| 300 mg | Highest dose in the 4-week ubiquinol study; inside the range reviewed |
| 400 to 600 mg | Inside the range reviewed; no trial we cite at these doses |
| Above 1,200 mg | Data judged insufficient by the 2006 review |
Electric Tiger CoQ10 200 mg directs one capsule a day (200 mg of ubiquinone, as low as $16.31 a bottle on subscription), and carries this warning: do not exceed the recommended dose; ask a physician before use if pregnant or nursing, under 18, taking medication (especially blood thinners) or with a medical condition. We make no benefit claim for it and give no reason to go above the label.
Questions people ask
Can you take too much CoQ10? Can you get too much?
Possibly, as with any supplement, but we found no dose at which harm has been shown. The 2006 review found no dose-related effects up to 1,200 mg a day, and judged the data above that insufficient. Stay with your label's dose.
Is 300 mg of CoQ10 too much? Is 300 mg too much for a day?
The 300 mg dose appears in the 4-week ubiquinol study with no clinically relevant lab, vital sign or ECG changes (Hosoe 2007), and sits inside the reviewed range. It is 1.5 times our capsule. Our label's dose is 200 mg and it says not to exceed it.
Is 400 mg of CoQ10 too much?
It is inside the range the 2006 review covered, and we have no trial at that dose in our sources. If you want a number higher than your product's label, ask your pharmacist or doctor first, particularly if you take medication.
Is 200 mg of CoQ10 too much?
200 mg is one-sixth of the 1,200 mg observed safe level, and it is our capsule's dose. See how much CoQ10 to take.
Can you overdose on CoQ10, or is CoQ10 toxic?
We found no overdose or toxicity data in our sources. If someone takes a large amount, call a poison centre or a doctor. Do not exceed the recommended dose on the label.
Is too much CoQ10 bad for you?
The sources we read don't show that, but they don't exclude it for individuals. If you have symptoms you think are linked, stop and ask a clinician; see CoQ10 side effects and who should not take CoQ10.
Sources
- Risk assessment for coenzyme Q10 (Ubiquinone) A 2006 review of the clinical literature found no dose-related side effects in studies from 60 to 1,200 mg a day.
- Study on safety and bioavailability of ubiquinol (Kaneka QH) after single and 4-week multiple oral administration to healthy volunteers In healthy volunteers, 90 to 300 mg a day of ubiquinol for 4 weeks raised blood levels without lab or ECG changes; it was not compared with ubiquinone.
- Effectiveness of Coenzyme Q10 Supplementation for Reducing Fatigue: A Systematic Review and Meta-Analysis of Randomized Controlled Trials Pooling 13 trials in 1,126 people, CoQ10 lowered fatigue scores modestly versus placebo, with larger effects at higher doses and longer durations.
- [Effect of Coenzyme Q10 and Ginkgo biloba on warfarin dosage in patients on long-term warfarin treatment. A randomized, double-blind, placebo-controlled cross-over trial] In 24 people on stable warfarin, 100 mg a day of CoQ10 for 4 weeks did not change INR or warfarin dose.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
