Can You Take GLP-1 Medications If You Have Hashimoto’s or Thyroid Cancer?
GLP-1 medications like Ozempic, Wegovy, Mounjaro, and Zepbound have become powerful tools for treating type 2 diabetes and obesity. But if you live with a thyroid condition, it’s completely normal to feel uncertain or anxious about whether these medications are safe for you.
At Unified Endocrine & Diabetes Care, we see patients across Lafayette and throughout California, including via telemedicine for individuals in Silicon Valley, Palo Alto, Menlo Park, San Francisco, Walnut Creek, Oakland, and Sacramento. This question comes up daily, and there is a lot of misinformation online.
Let’s walk through the science, clear up the confusion, and answer the five most commonly searched questions about GLP-1 medications and thyroid health.
1) Do GLP-1 Medications Cause Thyroid Cancer?
This is the most misunderstood concern surrounding GLP-1 therapy.
GLP-1 medications are not linked to most thyroid cancers in humans.
However, there is one very specific and important exception.
When GLP-1 medications are contraindicated
GLP-1 receptor agonists are contraindicated if you have:
A personal or family history of medullary thyroid cancer
A genetic condition called Multiple Endocrine Neoplasia type 2 (MEN-2)
This warning comes from animal studies where rodents developed C-cell tumors. These tumors are associated with medullary thyroid cancer. Humans have far fewer C-cells, and large human studies have not shown a clear causal link, but the precaution remains.
What about papillary or follicular thyroid cancer?
If you have a history of papillary or follicular thyroid cancer, also called differentiated thyroid cancer, current evidence does not show that GLP-1 medications cause or worsen these cancers.
For my patients in Lafayette, the Bay Area, or anywhere in California via telemedicine, this discussion is simplified and clarified so your questions, anxiety and fear are resolved with the right science. GLP-1 therapy is still an option when medically appropriate and carefully discussed with your endocrinologist.
2) Can You Take GLP-1 Medications If You Have Hashimoto’s or Hypothyroidism?
Yes.
Hashimoto’s thyroiditis and hypothyroidism are not contraindications to GLP-1 therapy.
These conditions are extremely common, particularly in women, and many patients safely use GLP-1 medications while on thyroid hormone replacement.
What to monitor
If you are taking levothyroxine and experience significant weight loss on a GLP-1 medication, your thyroid hormone requirements may change.
This is not due to thyroid damage, but rather because:
Weight loss alters hormone needs
Improved metabolic health can change dosing requirements
My Clinical guidance to patients:
If you lose 10–20 pounds, recheck thyroid labs within 8–12 weeks to avoid over- or under-treatment.
3) Do GLP-1 Medications Affect Thyroid Hormone Absorption?
GLP-1 medications slow gastric emptying, which naturally raises questions about medication absorption.
In most patients, thyroid hormone absorption remains stable. However, absorption can be affected if thyroid medication is taken too close to:
Food
Calcium or iron supplements
Antacids or acid-reducing medications
This discussion is essential at Unified Endocrine for our patients in Clovis, Silicon Valley, Sacramento, or who are seen virtually through California telemedicine.
Best practice:
Take thyroid medication on an empty stomach, space supplements appropriately, and recheck labs after starting GLP-1 therapy if you are losing substantial weight and discuss with your treating physician.
4) Can GLP-1 Medications Cause Thyroid Nodules or Swelling?
There is no scientific evidence that GLP-1 medications cause thyroid nodules or thyroid swelling.
Thyroid nodules are common and often benign. Many adults have small nodules that never cause problems.
If you already have a thyroid nodule:
Benign nodules are not a contraindication
Routine surveillance should continue as recommended
Screening ultrasounds are not required just because you start a GLP-1 medication
A physical exam and baseline thyroid labs are usually sufficient.
5) Who Should Not Take GLP-1 Medications?
Absolute contraindications
Medullary thyroid cancer
MEN-2
Pregnancy or breastfeeding
Prior severe allergic reaction to GLP-1 medications
Conditions requiring extra caution
Gastroparesis or delayed gastric emptying
History of pancreatitis
Advanced diabetic retinopathy
Use alongside medications that increase hypoglycemia risk
These and a few other situations require individualized assessment, which is why specialty endocrine care matters.
The Bottom Line
For many patients with thyroid conditions, GLP-1 medications can be used safely and effectively when guided by evidence and proper monitoring.
Key takeaways:
Hashimoto’s and hypothyroidism do not automatically disqualify you
Only medullary thyroid cancer and MEN-2 are true contraindications
Weight loss may require thyroid medication adjustment
Personalized endocrine care makes all the difference
Whether you’re located in Lafayette, San Francisco, the Bay Area, or anywhere in California via telemedicine, these decisions for my patients are always made through thoughtful, one-on-one discussions.
Have questions about GLP-1 therapy, thyroid health, or metabolic care?
Visit unifiedendocrinecare.com or reach out to our office to learn more about in-person visits in Fresno and Lafayette or California-wide telemedicine consultations.
Strong science. Clear answers. Personalized endocrine care.
By Dr. Chhaya Makhija, MD, DipABLM
Board-Certified Endocrinologist | Lifestyle Medicine Physician | Founder, Unified Endocrine & Diabetes Care
Lafayette • Fresno • California Telemedicine (including Silicon Valley, Palo Alto, Menlo Park, San Francisco, Walnut Creek, Oakland, Sacramento)
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