From the Research
Interactions between Fish Oil Supplements and Levothyroxine
- There is no direct evidence in the provided studies that specifically addresses the interaction between fish oil supplements and levothyroxine (T4, thyroxine) 1, 2, 3, 4, 5.
- However, one study suggests that omega-3 fatty acids, which are found in fish oil supplements, may have beneficial effects on hyperthyroidism-induced hepatic dysfunction in rats 3.
- Another study found that liquid and softgel formulations of levothyroxine can be taken with meals without affecting therapeutic efficacy, and may even improve patient compliance and quality of life compared to tablet formulations taken 30 minutes before breakfast 4.
- It is also noted that certain medications and supplements, such as calcium and iron supplements, can interfere with the bioavailability of levothyroxine, but there is no mention of fish oil supplements specifically 1, 2.
Potential Mechanisms of Interaction
- The proposed mechanisms of interaction between levothyroxine and other substances include direct complexing, alkalization, alteration of serum thyroxine-binding globulin levels, and acceleration of levothyroxine catabolism via deiodination 1.
- However, it is unclear whether these mechanisms would apply to fish oil supplements, and further studies would be needed to determine the potential interactions between fish oil supplements and levothyroxine.
Clinical Implications
- Clinicians, patients, and pharmaceutical companies should be aware of the possible interactions between levothyroxine and other substances, including medications and supplements 1, 2.
- Further well-designed studies are needed to provide more solid evidence on the treatment and mechanisms of interactions between levothyroxine and other substances, including fish oil supplements 1, 2.