Coenzyme Q10 - Synthroid (Levothyroxine) Interaction
Herbal: Coenzyme Q10
Also Known As: CoQ10
Drug: Levothyroxine
Brand names:
Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, Levo-T, Eltroxin, Estre, Levothyroxine, Novothyrox, Levolet
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Apr 20, 2025
Interaction Details
There were no interactions found between Levothyroxine and Coenzyme Q10. This does not mean the potential for an interaction does not exist, however. There is often a lack of studies and data surrounding traditional medicine, especially concerning drug interactions, so it is important to always consult your provider before making any changes to your medication regimen.
Pharmacist Analysis
Although CoQ10 is considered relatively safe for most individuals, it does have some reported interactions that are important to be aware of.
This includes:
- Antihypertensives: Clinical research has shown that CoQ10 can significantly lower blood pressure but conflicting results have been reported.
- Warfarin: Research is conflicting but concomitant use of CoQ10 and warfarin might reduce the anticoagulant effects of warfarin.
- Alkylating Agents: Antioxidants such as CoQ10 might also protect tumor cells from chemotherapeutic agents that work by inducing oxidative stress, such as alkylating agents (e.g., cyclophosphamide) and radiation therapy.
Outside of the interactions I've listed above, CoQ10 is generally considered safe to supplement with in most situations.
In fact, some individuals taking certain medications (e.g., 'Statins') may be recommended to take it.
If you have any questions about CoQ10 supplements, be sure to speak to your healthcare professional. We are always happy to answer questions on the matter as well!
- Dr. Brian Staiger, PharmDCoenzyme Q10 Overview
Levothyroxine Overview
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Levothyroxine is used to treat hypothyroidism (condition where the thyroid gland does not produce enough thyroid hormone). It is also used with surgery and radioactive iodine therapy to treat thyroid cancer. Levothyroxine is in a class of medications called hormones. It works by replacing thyroid hormone that is normally produced by the body.
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Without thyroid hormone, your body cannot function properly, which may result in poor growth, slow speech, lack of energy, excessive tiredness, constipation, weight gain, hair loss, dry, thick skin, increased sensitivity to cold, joint and muscle pain, heavy or irregular menstrual periods, and depression. When taken correctly, levothyroxine reverses these symptoms.
Coenzyme Q10 - More Interactions
Coenzyme Q10 interacts with 195 drugs
Interaction Rating Key
These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.
| Major | The combined use of these agents is strongly discouraged as serious side effects or other negative outcomes could occur. |
| Moderate | Use cautiously under the care of a healthcare professional or avoid this combination. A significant interaction or negative outcome could occur. |
| Minor | Be aware that there is a chance of an interaction. Watch for warning signs of a potential interaction. |
| Unknown | No interactions have been reported or no interaction data is currently available. |
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Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC
Drug descriptions are provided by MedlinePlus.
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Dr. Brian Staiger, PharmD
In addition to being a clinical pharmacist specializing in pharmacotherapy, Dr. Brian Staiger is a registered herbalist through the American Herbalist Guild. He has combined his passion for pharmacy practice with the study of medical ethnobotany to improve patient care. Feel free to reach out about any of your herbal or medication questions!
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