Last Chance - Mother's Day Sale

Last chance - Mother's Day Sale

For moms, thyroid health matters. Save $25 on our thyroid test kit or self-pay membership using code MOMDAY.

Can Antibiotics Affect Your Thyroid Health and Hypothyroidism

Learn more about the often-overlooked relationship between antibiotic treatment and your thyroid health.
Can Antibiotics Affect Your Thyroid Health and Hypothyroidism
Last updated:
Written by:
Medically Reviewed by:

In this article

Antibiotics are commonly prescribed medications that are used to fight bacterial infections. While they can be lifesaving in many cases, antibiotics can also have side effects and potential risks. One possible concern is the impact that antibiotics can have on thyroid health and hypothyroidism.

In this article, we’ll explore the effects of antibiotics on people with thyroid conditions. We’ll also discuss the importance of informed decision-making, open communication with your healthcare provider, and the significance of integrating thyroid health considerations into antibiotic therapy.

Antibiotics and gut health

Antibiotics, while not directly linked to causing an underactive thyroid, can indirectly affect thyroid function through their impact on gut microbiota, or “gut health.”

A healthy gut is beneficial for the overall immune system, especially for thyroid function. The gut microbiome, made up of trillions of microorganisms, plays a crucial role in maintaining intestinal barrier function, influencing the role of the immune system, and establishing nutrient metabolism. The composition of the gut also influences the availability of essential micronutrients for the thyroid gland, including iodine, iron, copper, selenium, zinc, and vitamin D. People with thyroid disease are also frequently deficient in these micronutrients. This direct relationship between the gut and the thyroid is also known as the thyroid-gut axis.

The thyroid gland, through its production of thyroid hormones, regulates gut motility (the movement of food from the mouth and out of the body), microbial composition, and immune responses within the gastrointestinal tract. Thyroid disease frequently coexists with intestinal diseases, and gut health can affect thyroid function.

The impact of antibiotics on gut health is vital to understand. While antibiotics are instrumental in combating again bacterial infections, they can disrupt the delicate balance of the gut microbiome. Even though antibiotics can target harmful bacteria, they also inadvertently deplete beneficial bacteria, leading to dysbiosis – an imbalance in the microbial communities within the gut. This dysregulation may manifest as decreased microbial diversity, alterations in microbial composition, and overgrowth of opportunistic pathogens. Antibiotics can also impair the integrity of the intestinal barrier, compromising its function as a barrier and exacerbating gut inflammation. This is known as having a “leaky gut.

One of the common causes or precursors to developing thyroid disease is an imbalance or dysbiosis of the gut. A condition such as leaky gut or intestinal inflammation can worsen autoimmune thyroid diseases such as hypothyroidism. Symptoms commonly observed in those with an underactive thyroid gland, including fatigue, weight gain, or cognitive impairment, may be worsened due to a gut health imbalance.

Antibiotics and thyroid medication

One of the more direct ways in which antibiotics can affect thyroid health is through interactions with thyroid hormone replacement medications. The antibiotics ciprofloxacin, levofloxacin, and lomefloxacin, for example, can alter the gastrointestinal tract, reducing thyroid hormone absorption and making treatment less effective. This interference can lead to variations in thyroid hormone levels, necessitating adjustments in the dosage of thyroid medications to maintain optimal thyroid levels. Patients on thyroid hormone replacement therapy should be closely monitored when prescribed these antibiotics, and their thyroid function should be checked regularly so that adjustments can be made as soon as possible when needed.

Antibiotics and iodine absorption

Some specific antibiotics negatively impact thyroid function directly or indirectly through one of the mechanisms essential to thyroid health. One way is to disrupt iodine absorption, a critical process for thyroid hormone synthesis.

Antibiotics such as sulfonamides (commonly used to treat infections) can interfere with iodine uptake by the thyroid gland, potentially impairing the production of thyroid hormones. This disruption of iodine absorption can lead to decreased thyroid hormone synthesis and subsequent hypothyroidism. Some antibiotics can alter thyroid hormone metabolism and thus impact the function of the thyroid. This includes a drug called amiodarone, which is commonly prescribed for cardiac arrhythmias or abnormal heartbeats. Amiodarone contains iodine molecules that structurally resemble thyroid hormone molecules. This can result in both hypo and hyperthyroidism, especially in those who receive long-term amiodarone therapy (14 to 18% of patients).

Lastly, tetracycline antibiotics can potentially affect thyroid hormone receptors. Tetracyclines are a class of medications that are used to manage and treat various bacterial infections. This interference with thyroid hormone receptors can impair thyroid hormone action, contributing to metabolism, growth, and development disturbances.

The mechanisms by which antibiotics interfere with thyroid function encompass a spectrum of disruptions, ranging from alterations in iodine absorption and hormone metabolism to impacts on thyroid hormone receptors. Understanding this is crucial for recognizing the potential risks associated with antibiotic therapy, particularly in individuals with preexisting thyroid disorders. Knowing this as a patient and communicating these concerns and questions with your healthcare provider can help them to tailor an approach to utilizing antibiotic management that would have minimal effects on thyroid health and optimize patient outcomes.

Managing thyroid health while taking antibiotics

With these factors in mind, what should you do when taking antibiotics? How can you both optimize the therapeutic outcomes of antibiotic use and reduce the impact on your thyroid function?  Proactive measures such as appropriate probiotic supplementation, dietary modifications, and diligent monitoring of thyroid function can play pivotal roles in safeguarding thyroid health during antibiotic use.

Supplement with probiotics

Probiotic supplementation emerges as a promising strategy to counteract disruptions in the gut microbiome by antibiotics. Probiotics work by replenishing beneficial bacteria, restoring microbial balance, mitigating dysbiosis-induced inflammation, and preserving the integrity of the intestinal barrier. Specific strains of probiotics, such as Lactobacillus and Bifidobacterium species, have been found effective in promoting gut health and improving gastrointestinal symptoms caused by antibiotics.

Check with your doctor when an antibiotic is prescribed to you to determine if they recommend a specific type of probiotic and how to dose it properly. If a probiotic supplement is not feasible, incorporate probiotic-rich foods such as yogurt, kefir, and fermented vegetables into your diet. These foods can complement probiotic supplementation and may even provide some support while taking antibiotics.

Modify your diet

Supporting your gut health through dietary and lifestyle measures can lessen the adverse effects of antibiotics on thyroid function. Here are some dietary changes to help:

  • Consume a nutrient-dense diet rich in fiber, prebiotics, and polyphenols to create a favorable environment for beneficial gut microbes to thrive.
  • Emphasize whole foods, including fruits, vegetables, whole grains, and lean proteins, to obtain essential nutrients and antioxidants for optimal gut and thyroid function.
  • Minimize the intake of processed foods, sugary beverages, and artificial additives to help mitigate inflammation and oxidative stress.

Monitor your thyroid function

Frequent monitoring of any hypothyroid symptoms during antibiotic treatment is crucial so you can detect any irregularities and intervene when needed. Regular thyroid function tests provide greater insight to your healthcare provider and allow them to gauge thyroid hormone production and adjust any treatments as required. Keep close and open communication between yourself and your doctor to recognize any new or worsening symptoms of hypothyroidism and any potential adverse effects or drug interactions to ensure optimal management of your thyroid condition while on antibiotics.

Dealing with Hypothyroidism?  Video chat with a thyroid doctor

Get answers and treatments in minutes without leaving home - anytime. Consult with a U.S. board certified doctor who only treats hypothyroidism via high-quality video. Insurance accepted.

A note from Paloma

It is important to note that not all antibiotics have a negative impact on patients with hypothyroidism, and the effects may vary depending on the individual and the specific antibiotic being used. However, if you are concerned about the impact of antibiotics on your thyroid health, it is essential to discuss these concerns with your healthcare provider.

We understand that thyroid health can be complex and, like a puzzle, involves many pieces that need to fit together. That is why Paloma is dedicated to helping simplify things for hypothyroid patients, clarifying any confusion, and providing all the options to keep you and your thyroid healthy. Contact Paloma Health to chat with one of your highly trained medical care providers. If you have not recently had your thyroid levels checked, look into Paloma’s at-home thyroid testing kit. Paloma’s convenient home kit tests thyroid-stimulating hormone (TSH), free thyroxine (Free T4), free triiodothyronine (Free T3), and thyroid autoantibodies (TPO) to provide a comprehensive picture of your thyroid health. Upon receiving your results, you can also take advantage of a virtual session with one of our knowledgeable doctors to help get you started on the path to wellness.


Knezevic J, Starchl C, Tmava Berisha A, Amrein K. Thyroid-Gut-Axis: How Does the Microbiota Influence Thyroid Function? Nutrients. 2020;12(6):1769. doi:

‌Sulfonamide (Oral Route) Side Effects - Mayo Clinic.

‌Zinner SH, Mayer KH. 33 - Sulfonamides and Trimethoprim. ScienceDirect. Published January 1, 20151.Pollock AJ, Seibert T, Allen DB. Severe and Persistent Thyroid Dysfunction Associated with Tetracycline-Antibiotic Treatment in Youth. The Journal of Pediatrics. 2016;173:232-234. doi:

‌Thyroid Dysfunction Induced by Amiodarone Therapy: Background, Pathophysiology, Epidemiology. eMedicine. Published online November 10, 2019.

Pollock AJ, Seibert T, Allen DB. Severe and Persistent Thyroid Dysfunction Associated with Tetracycline-Antibiotic Treatment in Youth. The Journal of Pediatrics. 2016;173:232-234. doi:

‌Shutter MC, Akhondi H. Tetracycline. PubMed. Published 2022.

Rodgers B, Kirley K, Mounsey A. Prescribing an antibiotic? Pair it with probiotics. The Journal of Family Practice. 2013;62(3):148-150.

Haugen BR. Drugs that suppress TSH or cause central hypothyroidism. Best Pract Res Clin Endocrinol Metab. 2009 Dec;23(6):793-800. doi: 10.1016/j.beem.2009.08.003. PMID: 19942154; PMCID: PMC2784889.

Share article:

Neeyaz Zolfaghari

Holistic Nutritionist and Nourishment Coach

Neeyaz Zolfaghari is the founder of Unspoken Nutrition, a nutrition and lifestyle brand dedicated to helping others find and create harmony with their daily habits to support their wellbeing and ‘health’. Her journey began over a decade ago, when she was diagnosed with two autoimmune diseases. Knowing what she learned from her upbringing, Neeyaz turned to nutrition as the first pillar of her healing. As her body began to heal on a physical level, she began to learn how our minds, bodies and souls are all innately connected.  

Now as an Integrative Nutritionist and Patient Advocate, Neeyaz offers the people she works with the support, guidance, and tools they need in order to live a fulfilled life. While Neeyaz initially endeavored to make a difference at the individual level, her vision grew to embrace broader community impacts. She is currently pursuing her Masters in Public Health, serving as a testament to her unwavering commitment to instigate change on a grander scale.

Read more

Is Paloma Right For Me?

Hypothyroidism is a long-term commitment and we’re committed to you. Schedule a free, no-obligation phone consultation with one of our intake specialists to find out more.

Schedule a call
thyroid hormone for hypothyroidism

Find out if Paloma is right for you. Schedule a free call with one of our health care advisors.

Schedule a Call