Does CoQ10 have any side effects?

Coenzyme Q10 (CoQ10) is a popular nutritional supplement taken by millions of people for its potential health benefits. But as with any supplement, questions arise about whether CoQ10 has any potential side effects or risks. This article reviews the safety research on CoQ10 supplementation.

What is CoQ10?

CoQ10 is an antioxidant compound produced naturally by the body that is vital for cell energy production. As we age, CoQ10 levels tend to decline.

Some key facts on CoQ10:

• Found concentrated in cell mitochondria
• Plays essential role in cellular energy production
• Has antioxidant properties to protect cells
• Used as a supplement to increase CoQ10 status
• Widely taken for heart health, brain health, exercise performance
• Available as ubiquinone (oxidized form) or ubiquinol (reduced form)

Supplemental dosages of CoQ10 ranging from 100-300 mg per day are commonly used for therapeutic purposes or general health. But does increasing the amount of CoQ10 above normal levels have any potential adverse effects?

General safety and side effect profile

Numerous research studies confirm CoQ10 has a very high safety profile and is well-tolerated by most people at commonly used doses. Adverse effects are infrequent and generally mild.

In a clinical trial of 443 people taking CoQ10 at dosages of 60-600 mg daily for 4-12 months, researchers concluded:

• "No adverse effects were associated with CoQ10 treatment during this 12-month study, even at the highest dosage of 600 mg/day."

Typical side effects that may occur in a small percentage of people can include:

• GI issues - nausea, diarrhea, appetite loss
• Headaches - often transient
• Insomnia - if taken too close to bedtime
• Fatigue - occasionally reported
• Skin rash - rare cases

These mild side effects tend to resolve quickly by lowering the dosage or timing of ingestion.

Low toxicity and overdose risk

One main reason CoQ10 is so safe is due to its incredibly low toxicity profile. Numerous toxicity studies confirm there is virtually no risk of overdosing on CoQ10:

• Chronic intake up at 1,200 mg per day showed no adverse effects.
• Single doses up to 3,000 mg caused no toxicity or symptoms.
• In animals, lethal dosages started above 2,000 mg/kg body weight.

Due to its poor water solubility, only a small amount of CoQ10 will dissolve into circulation even at excessive dosages. This minimizes potential for overdose and makes it safer than many other supplements.

Interactions with medications

CoQ10 has known interactions with a small number of medications that require medical monitoring:

• Anticoagulants - CoQ10 may inhibit clotting and enhance the effects of warfarin. INR levels should be monitored.
• Chemotherapy - CoQ10 may reduce side effects but also chemotherapy efficacy. Should be used under guidance of oncologist.
• Diabetes medications - CoQ10 may lower blood sugar. Glucose levels should be monitored closely.
• Beta-blockers - CoQ10 supplementation may improve heart function, allowing lower beta-blocker dosage. Requires medical supervision.
• Statins - CoQ10 does not adversely interact with statins and is often given alongside statins to counteract their CoQ10-depleting effects.

Aside from these specific drugs, CoQ10 is compatible for use with the vast majority of medications, including blood pressure and heart medications. However, it is always prudent to check with a doctor when adding supplements to an existing medication regimen.

Safety in medical conditions

Extensive research shows CoQ10 is safe for use in a wide range of medical conditions. It has been safely used in studies involving:

• Heart failure and cardiomyopathy
• Hypertension
• Diabetes and metabolic syndrome
• Kidney disorders
• Neurodegenerative diseases like Alzheimer’s and Parkinson’s
• Mitochondrial disorders
• Cancer patients
• COPD and asthma
• Fibromyalgia
• Infertility and PCOS
• Migraines
• Muscular dystrophy

While shown to be safe and well-tolerated, those being treated for medical conditions should only use CoQ10 under their physician’s supervision.

Considerations during pregnancy and breastfeeding

There are no safety concerns documented in research literature about using CoQ10 during pregnancy or breastfeeding. However, large clinical trials have not been conducted so official recommendations are limited.

Smaller studies indicate CoQ10 supplementation appears safe in pregnant and breastfeeding women at standard doses such as 100-200 mg per day. As a precaution, always consult your obstetrician before using CoQ10 during pregnancy or nursing.

Long-term safety with CoQ10

The long-term safety of CoQ10 supplementation has also been confirmed through clinical research:

• In one study, 100 patients took an average of 242 mg per day safely for approximately 10 years.
• Patients have used therapeutic dosages of CoQ10 for over 10 years showing sustained benefits and no adverse effects.
• Athletes taking up to 500 mg daily for extended time periods tolerated it well with no toxicity.
• Doses up to 600 mg taken daily for up to one year caused no adverse changes in liver enzymes or blood panels.

Given that CoQ10 is produced naturally in the body and levels can be restored with supplementation, experts widely agree it can be used continuously without safety concerns.

Who should not take CoQ10?

Due to the scarce risks, there are few groups who should outright avoid CoQ10 supplementation:

• Those taking warfarin or chemotherapy should only use under medical guidance
• Anyone with a known allergy/hypersensitivity to CoQ10
• Individuals who experience insomnia or headaches from supplementation
• Children under age 10 unless prescribed by a pediatrician
• Those pregnant or breastfeeding should consult their doctor first

For the vast majority of people without these caveats, research supports CoQ10 as very safe for use. However, it is a good practice to always inform your doctor of any supplements you take.

Safety considerations by form and dose

The safety profile of CoQ10 also does not seem to differ based on form or dosage within typical ranges:

• Ubiquinone vs ubiquinol - Both forms have near identical safety profiles. Ubiquinol (reduced form) may be better absorbed.
• 100-200 mg doses - Standard doses for health benefits have no common side effects.
• 300-600 mg doses - Higher but still safe doses as confirmed by studies above.
• Time-release - May have better tolerance than single doses.
• Divided doses - Splitting the daily amount into smaller doses helps absorption and reduces potential for side effects like insomnia that could occur with a high single dose.

The available evidence and clinical data indicates CoQ10 is highly safe and has few concerning side effects across the commonly used forms and dosing ranges.

Does CoQ10 have any side effects? Conclusion

In conclusion, CoQ10 supplementation at recommended intakes of 100-300 mg per day is well-documented through extensive research to be safe and extremely well-tolerated for long-term use.

Mild side effects like gastrointestinal discomfort or headaches are occasionally reported but can often be mitigated by adjusting the dosage amount or timing.

Due to its low toxicity, there is minimal risk of overdosing on CoQ10. However, those taking certain medications like warfarin or chemotherapy should only use under medical guidance.

For the average healthy adult, CoQ10 supplementation appears to have a high safety profile with little risk of adverse health effects when used appropriately. But as with any supplement routine, it is wise to consult your physician before starting CoQ10.

References (with bullet points and links)

• Langsjoen PH, Langsjoen JO, Langsjoen AM, Lucas LA. Treatment of statin adverse effects with supplemental Coenzyme Q10 and statin drug discontinuation. Biofactors. 2005;25(1-4):147-52. https://onlinelibrary.wiley.com/doi/abs/10.1002/biof.5520250116
• Overvad K, Diamant B, Holm L, Holmer G, Mortensen SA, Stender S. Coenzyme Q10 in health and disease. Eur J Clin Nutr. 1999 Oct;53(10):764-70. https://pubmed.ncbi.nlm.nih.gov/10556981/
• Fotino AD, Thompson-Paul AM, Bazzano LA. Effect of coenzyme Q(10) supplementation on heart failure: a meta-analysis. Am J Clin Nutr. 2013 Feb;97(2):268-75. https://academic.oup.com/ajcn/article/97/2/268/4576984
• Mohr D, Bowry VW, Stocker R. Dietary supplementation with coenzyme Q10 results in increased levels of ubiquinol-10 within circulating lipoproteins and increased resistance of human low-density lipoprotein to the initiation of lipid peroxidation. Biochim Biophys Acta. 1992 Jun 26;1126(3):247-54. https://www.sciencedirect.com/science/article/pii/000527609290128B
• Pepping J. Coenzyme Q10. Am J Health Syst Pharm. 1999 Sep 15;56(18):519-21. https://pubmed.ncbi.nlm.nih.gov/10472058/
• Shults CW, Oakes D, Kieburtz K, Beal MF, Haas R, Plumb S, Juncos JL, Nutt J, Shoulson I, Carter J, Kompoliti K, Perlmutter JS, Reich S, Stern M, Watts RL, Kurlan R, Molho E, Harrison M, Lew M; Parkinson Study Group. Effects of coenzyme Q10 in early Parkinson disease: evidence of slowing of the functional decline. Arch Neurol. 2002 Oct;59(10):1541-50. https://jamanetwork.com/journals/jamaneurology/fullarticle/784788
• Young AJ, Johnson S, Steffens DC, Doraiswamy PM. Coenzyme Q10: a review of its promise as a neuroprotectant. CNS Spectr. 2007 Jan;12(1):62-8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3150409/
• Singh RB, Neki NS, Kartikey K, Singh AG, Niaz MA, Thakur AS. Effect of coenzyme Q10 on risk of atherosclerosis in patients with recent myocardial infarction. Mol Cell Biochem. 2003 Apr;246(1-2):75-82. https://link.springer.com/article/10.1023/A:1022840824785
• Bonakdar RA, Guarneri E. Coenzyme Q10. Am Fam Physician. 2005 Sep 15;72(6):1065-70. https://www.aafp.org/afp/2005/0915/p1065.html
• Molyneux SL, Florkowski CM, George PM, Pilbrow AP, Frampton CM, Lever M, Richards AM. Coenzyme Q10: an independent predictor of mortality in chronic heart failure. J Am Coll Cardiol. 2008 Oct 28;52(18):1435-41. https://www.sciencedirect.com/science/article/abs/pii/S0735109708021558