Does Levothyroxine Cause Cancer? Study of Over 600,000 Thyroid Patients Explained
A new study of over 600,000 thyroid patients from Taiwan suggested that thyroid patients taking levothyroxine have a 50% increased risk of developing cancer at any site. While concerning, the results of this study certainly do not prove that levothyroxine causes cancer but every thyroid patient taking levothyroxine should be aware of this potential connection.
https://onlinelibrary.wiley.com/doi/10.1111/cas.14908
This information is not meant to cause fear or alarm but to simply break down this study, explain some of the issues with the study, and some of the key takeaways.
Let’s start with the problems first:
#1. The study was retrospective. Retrospective studies look backward in time at existing data and can show a correlation between things but do not necessarily prove causation. This is very important because many thyroid patients suffer from conditions that can also increase cancer risk and these must be taken into account.
#2. More research is still needed before any definitive conclusion is made. This is only one study and before any claim can be definitely made, there must be other studies that account for the issues listed above.
#3. We don’t have information on other thyroid medications. This study only took into account levothyroxine and didn’t account for other thyroid medications that may be better for thyroid management such as NDT formulations.
#4. Even though levothyroxine is synthetic, it is still bioidentical. The fact that levothyroxine is body identical or bioidentical is good because it means it’s less likely to result in cancer. Bioidentical hormones can impact cancer risk but typically only if they are dosed incorrectly (either too much or too little).
Some key takeaways and lessons from this study include:
#1. Don’t take thyroid medication unless you need it! I have many articles and videos which can help you determine if you are someone that may be able to get off of their thyroid medication.
#2. It may be difficult for some thyroid patients to get thyroid medication from here on out. This can be both a good and a bad thing.
#3. Instead of getting worried about what thyroid medication you are taking, focus more on the dose of that medication. Focus more on optimizing your free thyroid hormone levels as that will probably have the biggest impact on your risk of cancer.
#4. Even if you can’t control your thyroid medication you can still control other factors which can influence your own personal risk of cancer. Eating healthy whole foods, avoiding alcohol, exercising regularly, avoiding smoking, and so on can all impact your cancer risk.
Download my free thyroid resources here (including hypothyroid symptoms checklist, the complete list of thyroid lab tests + optimal ranges, foods you should avoid if you have thyroid disease, and more): https://www.restartmed.com/start-here/
Recommended thyroid supplements to enhance thyroid function:
- Supplements that everyone with hypothyroidism needs: https://bit.ly/3tekPej
- Supplement bundle to help reverse Hashimoto’s: https://bit.ly/3gSY9eJ
- Supplements for those without a thyroid and for those after RAI: https://bit.ly/3tb36nZ
- Supplements for active hyperthyroidism: https://bit.ly/3t70yHo
See ALL of my specialized supplements including protein powders, thyroid supplements, and weight loss products here:
https://www.restartmed.com/shop/
Want more from my blog? I have more than 400+ well-researched blog posts on thyroid management, hormone balancing, weight loss, and more. See all blog posts here:
https://www.restartmed.com/blog/
Prefer to listen via podcast? Download all of my podcast episodes here: https://apple.co/3kNYTCS
Disclaimer:
Dr. Westin Childs received his Doctor of Osteopathic Medicine from Rocky Vista University College of Osteopathic medicine in 2013. His use of “doctor” or “Dr.” in relation to himself solely refers to that degree. Dr. Childs is no longer practicing medicine and does not hold an active medical l
https://onlinelibrary.wiley.com/doi/10.1111/cas.14908
This information is not meant to cause fear or alarm but to simply break down this study, explain some of the issues with the study, and some of the key takeaways.
Let’s start with the problems first:
#1. The study was retrospective. Retrospective studies look backward in time at existing data and can show a correlation between things but do not necessarily prove causation. This is very important because many thyroid patients suffer from conditions that can also increase cancer risk and these must be taken into account.
#2. More research is still needed before any definitive conclusion is made. This is only one study and before any claim can be definitely made, there must be other studies that account for the issues listed above.
#3. We don’t have information on other thyroid medications. This study only took into account levothyroxine and didn’t account for other thyroid medications that may be better for thyroid management such as NDT formulations.
#4. Even though levothyroxine is synthetic, it is still bioidentical. The fact that levothyroxine is body identical or bioidentical is good because it means it’s less likely to result in cancer. Bioidentical hormones can impact cancer risk but typically only if they are dosed incorrectly (either too much or too little).
Some key takeaways and lessons from this study include:
#1. Don’t take thyroid medication unless you need it! I have many articles and videos which can help you determine if you are someone that may be able to get off of their thyroid medication.
#2. It may be difficult for some thyroid patients to get thyroid medication from here on out. This can be both a good and a bad thing.
#3. Instead of getting worried about what thyroid medication you are taking, focus more on the dose of that medication. Focus more on optimizing your free thyroid hormone levels as that will probably have the biggest impact on your risk of cancer.
#4. Even if you can’t control your thyroid medication you can still control other factors which can influence your own personal risk of cancer. Eating healthy whole foods, avoiding alcohol, exercising regularly, avoiding smoking, and so on can all impact your cancer risk.
Download my free thyroid resources here (including hypothyroid symptoms checklist, the complete list of thyroid lab tests + optimal ranges, foods you should avoid if you have thyroid disease, and more): https://www.restartmed.com/start-here/
Recommended thyroid supplements to enhance thyroid function:
- Supplements that everyone with hypothyroidism needs: https://bit.ly/3tekPej
- Supplement bundle to help reverse Hashimoto’s: https://bit.ly/3gSY9eJ
- Supplements for those without a thyroid and for those after RAI: https://bit.ly/3tb36nZ
- Supplements for active hyperthyroidism: https://bit.ly/3t70yHo
See ALL of my specialized supplements including protein powders, thyroid supplements, and weight loss products here:
https://www.restartmed.com/shop/
Want more from my blog? I have more than 400+ well-researched blog posts on thyroid management, hormone balancing, weight loss, and more. See all blog posts here:
https://www.restartmed.com/blog/
Prefer to listen via podcast? Download all of my podcast episodes here: https://apple.co/3kNYTCS
Disclaimer:
Dr. Westin Childs received his Doctor of Osteopathic Medicine from Rocky Vista University College of Osteopathic medicine in 2013. His use of “doctor” or “Dr.” in relation to himself solely refers to that degree. Dr. Childs is no longer practicing medicine and does not hold an active medical l
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