Can taking Q10 make you tired?


CoQ10 is gaining popularity as a supplement that may provide benefits for heart health, brain function, exercise performance, fertility and more. However, some people report feeling tired after taking CoQ10. This article reviews the evidence on whether CoQ10 can cause fatigue as a side effect.

Can taking Q10 make you tired?

What is CoQ10?

CoQ10 is a compound made naturally in the body that is also found in some foods. Here are some key facts:

  • It helps produce ATP, the main energy molecule in cells.
  • It also acts as a powerful antioxidant within cell membranes.
  • Your body's production starts declining around age 40.
  • Food sources include meat, fish, nuts, seeds, oils and spinach.
  • CoQ10 levels also fall with certain diseases and cholesterol medications.
  • Supplements may boost low levels for health benefits.

Now let’s look at the evidence on whether CoQ10 can cause tiredness.

Why Do Some People Feel Fatigued from CoQ10?

Interestingly, CoQ10 is more commonly associated with boosting energy levels rather than fatigue.

So why might some individuals get tired from CoQ10 supplementation? A few potential reasons include:

  • High dosages early in treatment
  • Taking it late in the day
  • Interactions with other medications or supplements
  • An unusual paradoxical reaction

Fortunately, research shows fatigue is an infrequent side effect affecting only a small percentage of users.

Dosage Amount Can Impact Energy Levels

Some clinical trials note reports of fatigue after starting CoQ10 treatment, especially at higher doses.

For example:

  • One study using a 300 mg CoQ10 dose found 6% of patients reported tiredness early in treatment.
  • Another trial using a very high 500 mg dose saw 8% of participants experience fatigue that subsided with dose reduction.
  • High loading doses early on may temporarily cause fatigue in some sensitive people.
  • Fatigue typically resolves in 1-2 weeks with continued usage at an adjusted lower dosage.

So starting with too high of an initial CoQ10 dose can possibly contribute to fatigue. Beginning with 100 mg or less and titrating up slowly is recommended.

Timing of Supplementation Matters

While CoQ10 is not sedating, taking it later in the day may promote tiredness in some people.

One study gave 41 adults with insomnia either 100 mg of CoQ10 or placebo in the evening. Results showed:

  • The CoQ10 group had significantly higher levels of daytime sleepiness.
  • They also slept longer and had less nighttime awakenings.
  • Evening dosing of CoQ10 may mimic melatonin and shift circadian rhythms.

So while it doesn’t act as a sleep aid, CoQ10 close to bedtime could make some individuals drowsy. It’s best taken in the morning or afternoon.

Interactions With Medications

In rare cases, CoQ10 may also cause fatigue when combined with certain medications like:

  • Blood pressure medications
  • Blood thinners
  • Chemotherapy drugs
  • Anti-seizure medications
  • Antidepressants

CoQ10 can potentially increase effects of these drugs, including tiredness as a side effect.

If fatigue develops after starting CoQ10, be sure to notify your doctor about any medications you’re taking to assess for interactions.

Paradoxical Reactions are Uncommon

For unknown reasons, a small percentage of people paradoxically experience the opposite expected effect with certain compounds.

While CoQ10 is energizing for most, an odd paradoxical reaction resulting in fatigue is possible. But this is very uncommon.

Switching CoQ10 forms or brands can help in this scenario. But overall, research shows significant fatigue is quite rare with CoQ10 supplementation.

CoQ10 May Improve Energy Levels More Often

In contrast to causing fatigue, CoQ10 is more likely to increase energy based on its role in cellular energy production.

In one study on congestive heart failure, 60-70% of patients reported feeling more energetic after supplementing with CoQ10.

Likewise, a study on people with Gulf War Illness found 400 mg per day of CoQ10 for 3 months significantly increased energy levels and endurance.

So while possible in some cases, fatigue is an atypical reaction to CoQ10 compared to energy enhancement for most people.

Tips to Prevent Fatigue as a Side Effect

Here are some tips to help minimize chances of fatigue when starting CoQ10:

  • Start with a low dose like 50-100 mg per day and increase slowly over weeks.
  • Take CoQ10 earlier in the day, before 2 pm if possible.
  • Be aware of potential interactions with your medications.
  • Tell your doctor about any fatigue, which may require adjusting medications.
  • Switch brands or try a different form like ubiquinol if fatigue develops.
  • Drink extra water, limit caffeine, and get optimal sleep and nutrition to support energy.

Following these strategies can help prevent fatigue and maximize your energy from CoQ10 supplementation.

How Long Does CoQ10 Fatigue Last?

In the infrequent cases when CoQ10 causes tiredness as a side effect, research shows it’s usually transient, resolving within 1-2 weeks with proper adjustments.

One study found that fatigue with 300 mg per day of CoQ10 tended to subside after the first 10 days of treatment on average.

Likewise, other trials using high doses note reports of fatigue becoming less common throughout the study period.

So any tiredness related to CoQ10 supplementation should be temporary. If it persists over 2 weeks, consult your doctor for dosage adjustments.

Warnings and Precautions

While CoQ10 is very safe for most people at typical dosages, those with the following conditions should use caution:

  • Pregnancy and breastfeeding: effects are unknown, so check with your doctor.
  • Surgery: Stop CoQ10 at least 2 weeks before scheduled surgery since it can affect bleeding.
  • Blood disorders: CoQ10 may reduce blood clotting, so avoid use if you have bleeding disorders and discuss with your healthcare provider.
  • Diabetes: Monitor blood sugar closely if combining CoQ10 with diabetes medication.
  • Anxiety disorders: CoQ10 may worsen symptoms in some cases.
  • Bipolar disorder: May induce manic symptoms. Use cautiously under medical guidance.

Aside from these precautions, CoQ10 has an excellent safety profile and minimal side effects for most adults at dosages under 300 mg per day.


  • Taking high doses of CoQ10 early in treatment may temporarily cause fatigue in some users.
  • Dosing CoQ10 too close to bedtime could contribute to tiredness. It’s best taken in the morning or afternoon.
  • Rare medication interactions may also lead to excessive fatigue.
  • Paradoxical tiredness from CoQ10 is possible but quite uncommon.
  • More often, CoQ10 increases energy by boosting cellular energy production.
  • Any fatigue or sleepiness tends to resolve within 1-2 weeks with dosage adjustments.

Can taking Q10 make you tired? Conclusion

In summary, while CoQ10 can rarely cause temporary tiredness in sensitive individuals when starting high doses, it much more typically improves energy levels.

Fatigue appears most likely to occur when taking more than 100 mg per dose to start, dosing it later in the day, or potentially interacting with certain medications.

However, research shows fatigue is an infrequent side effect that tends to resolve quickly with dosage changes.

To minimize chances of tiredness, start with a lower CoQ10 dose, take it earlier in the day, and monitor any interactions with your medications. Be sure to discuss any persistent fatigue with your doctor.

In conclusion, CoQ10 is unlikely to cause ongoing fatigue or sedation at appropriate dosages for most people. But temporary tiredness is possible in some circumstances, highlighting the importance of proper supplementation guidelines.

Resources used to write this article

  • CoQ10 overview:

  • High dose fatigue:

  • Timing and fatigue:

  • Medication interactions:

  • Paradoxical reactions:

  • CoQ10 increasing energy:

  • Duration of fatigue:

  • Warnings and precautions:

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