Thyroid Medications: A Comprehensive Guide

Dr. Jolene BrightenPublished: Last Reviewed: Thyroid, Thyroid & Hormone Balance Leave a Comment

Levothyroxine is the most common thyroid medication to treat hypothyroidism, but as you’ll learn in this article, there are several other thyroid medication options. As a board certified naturopathic endocrinologist, I have found that patients can respond differently to thyroid medication, which means what works for one person, may not work for another.

Thyroid function is critical to overall health. Every cell in the body responds to thyroid hormones, which set the metabolic rate and drive cell functions. If your thyroid isn’t working correctly, you can experience many symptoms, like cold intolerance, constipation, dry skin, and fatigue.

In women’s health, we can’t overlook the importance of the thyroid gland and the hormones it produces. Women are more likely to experience thyroid imbalances, especially low thyroid hormones (hypothyroidism) and Hashimoto’s thyroiditis, the autoimmune disease that causes low levels of thyroid hormone production.

Symptoms associated with underactive thyroid gland or low serum thyroid hormone levels include:

  • Fatigue
  • Brain fog
  • Constipation
  • Weight gain
  • Depression
  • Hair loss
  • Muscle aches
  • Cold hands and feet
  • Dry skin
  • Fertility issues
  • Low blood pressure

To learn more about thyroid hormones, hypothyroidism, and symptoms, please read 10 Signs You Have Hypothyroidism.

In addition, thyroid hormones are essential for ovarian hormone production and ovulation, which can affect fertility, pregnancy, and more.

Sometimes, it is necessary to take a thyroid hormone medicine when the body cannot maintain healthy thyroid hormone levels on its own. Thyroid hormone replacement therapy is absolutely necessary if your levels are too low. Without supplementation of thyroid hormone we find that our mortality and morbidity risks increase.

What I explain to patients is that if someone has type 1 diabetes and is unable to t make insulin, they’d have to take insulin in order to stay alive. The same is true when thyroid disease leaves you with too little hormone; thyroid hormone replacement therapy is critical.

If you've had surgical removal of your thyroid, have had an injury to the pituitary gland, are experiencing a decline in thyroid function tests, or have an autoimmune disorder that has made your thyroid gland unable to produce adequate hormones, you'll want to explore the treatment options in this article. 

This article is a comprehensive guide to hypothyroid medications, as well as other treatments for hypothyroidism. I’ll cover the different types of oral medications, benefits, drawbacks, and best practices. I’ll also answer your FAQs and provide the information you need to make informed decisions about your thyroid health.

Types of Thyroid Medications

Several categories of thyroid medications are available by prescription from your healthcare provider to treat low thyroid hormones. It’s helpful to understand the type of thyroid replacement therapy medication you are taking and how it works in the body, along with the thyroid hormone dosages you're being prescribed.

Treatment with Levothyroxine (T4)

Levothyroxine (or L-thyroxine) is a synthetic version of the thyroid hormone called thyroxine or T4. T4 is the primary hormone made by the thyroid gland from the amino acid tyrosine and four iodine molecules. The inactive thyroid hormone must be converted to triiodothyronine, T3, the active thyroid hormone in order to be used by the cell. We'll discuss ways to support your body in converting T4 to T3 shortly.

Levothyroxine is a commonly prescribed thyroid medication and is considered the standard of care in thyroid hormone replacement.

Levothyroxine preparations available under the U.S. brand names:

  • Levoxyl
  • Synthroid
  • Levothroid
  • Tirosint
  • Tirosint-Sol
  • Unithroid
  • Levothyroxine (generic)

Daily levothyroxine doses can range from 25 mcg to over 150 micrograms. Dosages of levothyroxine must be individualized and monitored with serum thyroid hormone levels. Generic and brand name levothyroxine products should have the same effect, although some patients report differences in symptoms associated with different preparations.

Treatment with Liothyronine (T3)

Liothyronine (L-triiodothyronine) is the synthetic version of the active thyroid hormone T3. When absorbed as a medication, liothyronine doesn’t require conversion. It is immediately used by the body. It may be helpful thyroid drug when someone has difficulty converting T4 to T3.

Brand names of liothyronine include:

  • Cytomel
  • Triostat
  • Liothyronine (generic)

Triiodothyronine in patients can lead to excessive thyroid hormone symptoms, such as heart palpitations, diarrhea, insomnia, and sweating. It's important to monitor symptoms and serum thyroid hormone levels when taking this medication. 

If serum thyroid hormone levels reveal elevated T4 and T3, bone mineral density may be impacted, especially if a patient is at risk for osteoporosis. This is why some providers may be hesitant to use T3 or may ask a patient to reduce the dosage until their free T4 and free T3 are within normal range.

Combination Medications (T4/T3)

T4/T3 combination medications contain levothyroxine and liothyronine to replace both thyroid hormones. It’s recommended to try combination therapy when you still experience symptoms of hypothyroidism despite treatment with levothyroxine.

The synthetic combination option is:

  • Thyrolar (Liotrix)

Note that you could also take levothyroxine replacement dose with a liothyronine medication as separate medications at the same time to for more dosage options.

Natural Desiccated Thyroid (NDT)

Another combination therapy is natural desiccated thyroid (NDT) made from the thyroid glands of pigs. NDT is also known as natural thyroid, thyroid extract, or porcine thyroid. NDT includes T4 and T3, along with T2 and T1. The ratio of T4 to T3 is approximately 4 to 1.

This medication is standardized to it's iodine content. While it is considered a “natural” treatment of hypothyroidism by some, it's important to recognize that all thyroid medications are bioidentical hormones—meaning they are structurally the same as what your thyroid gland makes and the effects of thyroid hormones are the same.

Brand names include:

  • Armour Thyroid
  • Nature-throid
  • NP Thyroid

Compounded T4/T3

Thyroid replacement therapy combining T4 and T3 is also available from compounding pharmacies. Your doctor will help you identify the correct dosage and ratio, and the personalized medication will be made just for you.

Pros and Cons of Different Thyroid Medications

A 2021 study compared the effectiveness of T4, T4/T3, and NDT medications and found them to be comparatively effective in treating hypothyroidism. However, people who were symptomatic using daily levothyroxine doses alone preferred the combination therapies.

Like all medical therapies, thyroid replacement must be tailored to your individual needs and the dose of replacement medication will impact symptoms. Let’s look at the pros and cons of each category of thyroid medication.

Levothyroxine (T4)

Pros: Levothyroxine is stable and offers consistent, reliable dosing. It’s widely available and prescribed by doctors, so it’s easy to access when needed. It is often covered by insurance or may be a more affordable option.

Cons: When you take T4 alone, the body needs to convert (activate) it to T3; some may have difficulty with this conversion. While levothyroxine may help normalize TSH levels, it may not always optimize T3 levels. TSH (thyroid stimulating hormone) is the pituitary hormone that signals the thyroid gland to make thyroid hormones. TSH is the most common thyroid lab test used to monitor the dose of replacement medication.

Nutrients like zinc and selenium, as well as exercise, can help with the conversion of T4 to T3. We’ll discuss additional ways to support thyroid health shortly.

Liothyronine (T3)

Pros: Because Liothyronine is already the active form of thyroid hormone (T3), it can provide rapid symptom relief by providing T3 quickly and directly to cells.

Cons: T3 has a shorter half-life compared to T4. In addition, too much T3 can cause hyperthyroid symptoms (overactive thyroid), and there is a potential for overdosing. When dosed too high, it can have a bone wasting effect.

Combination Medications (T4/T3)

Pros: Combination medication contains both T4 and T3 in balanced levels and possibly has a greater potential for hypothyroid symptom improvement.

Cons: Dosing combination medications can be complex and take time and testing to dial in what your body needs. Additionally, this option may have less availability or expensive. Just as excess T3 can have a bone-wasting effect, a combination T4/T3 medication may also compromise bone mineral density. Postmenopausal women and elderly women may be at greatest risk.

Natural Desiccated Thyroid (NDT)

Pros: NDT contains the full spectrum of thyroid hormones (T4, T3, T2, and T1). T2 may have benefits for mitochondrial and ovarian health in women with hypothyroidism.

Cons: Because NDT comes from a natural source (pig thyroid glands), dosing is less consistent as there can be variability between batches. In addition, NDT may contain potential allergens. It is also derived from a pig, which may be important if you follow a strict vegan diet or avoid pork for religious reasons. Additionally elderly women and postmenopausal women should be monitored to avoid compromising bone mineral density.

Conversion of T4 to T3 and Receptor Binding

The thyroid gland makes T4 and T3, although over 80% is T4 that needs to convert to T3. T3 is the active thyroid hormone that binds to thyroid receptors in the nucleus of cells, where DNA is used to make proteins that regulate the cell’s metabolism (the metabolic rate).

The primary conversion site is the liver, but T4 to T3 conversion also happens in the gut, kidneys, and other tissues.

Nutrients for Thyroid

Thyroid production, transport, conversion, and function within cells requires several key micronutrients, including:

  • Tyrosine – an amino acid component of thyroid hormones
  • Iodine – component of thyroid hormones
  • Selenium – involved in T4 to T3 conversion
  • Vitamin A – required for the thyroid receptor
  • Vitamin D – supports immune health
  • Omega-3s – reduce inflammation to improve T4 to T3 conversion and receptor binding

You’ll find these nutrients in whole foods you can include as part of a thyroid-supportive diet and supplements, including the Dr. Brighten Essentials Thyroid Support, and the Thyroid Support Kit. You can read more about supplements that support thyroid health, including myo-inositol here.

Other Factors that Affect Conversion and Receptor Binding of Thyroid Hormones

Having thyroid nutrients on board is only half of the puzzle. Other factors can get in the way of T4 to T3 conversion and the ability of T3 to bind to the thyroid receptors in cells. These include:

  • Inflammation
  • Stress and elevated cortisol
  • Elevated estrogen or estrogen dominance
  • Low progesterone
  • Exposure to endocrine-disrupting toxins
  • Very Low Carbohydrate Dietary Pattern
  • Dieting and calorie restriction
  • Poor sleep
  • Gut infections and microbiome imbalances
  • The use of certain medications

Luckily, you can manage many of these factors with lifestyle change and a naturopathic root cause approach.

Best Practices for Taking Thyroid Medication

Following best practices when using thyroid medications will make the drug more effective and help you determine your optimal medication type and dosage more quickly and reliably.

Importance of Consistent Timing with Daily Dose of Thyroid Hormone

It’s essential to take your thyroid medication at the same time every day and follow a consistent daily dose of thyroid hormone for the best results. Skipping thyroid medication could result in symptoms of hypothyroidism. Additionally, taking medication inconsistently can affect thyroid function tests.

In most cases, it is recommended to take thyroid hormone replacement first thing in the morning with plain water for best absorption.

Interactions with Food, Coffee, and Minerals

People with hypothyroidism who are using oral medications should avoid taking them with food, coffee, and minerals, which can inhibit absorption of thyroid hormone. Anything that interferes with absorption will alter the actual dose of replacement medication you are getting and could lead to symptoms of hypothyroidism.

After taking your thyroid medication on an empty stomach with water, wait at least thirty minutes, if not an hour before consuming coffee or eating breakfast.

In addition, wait 4 hours before taking mineral supplements including calcium, iron, and magnesium. Note that minerals are often in multivitamins.

Additionally, soy may decrease medication absorption. If you consume soy products, wait 2-3 hours after taking thyroid medication.

Thyroid Medications and Drug Interactions

Thyroid drug interactions are common, but easily avoided. Always discuss all the medications, over-the-counter medications, and supplements with your prescribing provider and pharmacist, as there can be interactions with thyroid medications.

You may need to separate thyroid replacement medication from other medications, including heartburn and cholesterol-lowering medications, as these can affect absorption.

Optimal Absorption

Absorption of thyroid medication is critical and is affected by dietary fat, dietary fiber, coffee, alcohol, mineral supplements, soy, and more. If you change your diet or supplement routine significantly, check in with your doctor. In some cases, medication dosing may need adjusting as your lifestyle shifts.

For optimal absorption, take your medication on an empty stomach with water first thing in the morning. Wait 30-60 minutes before breakfast or coffee. Wait several hours before eating soy or taking supplements that contain minerals like calcium, iron, and magnesium.

What is the Most Common Thyroid Medication?

Levothyroxine (T4) is the most prescribed and widely available thyroid medication. It is considered the standard of care in cases of hypothyroidism and Hashimoto’s thyroiditis, an inflammatory thyroid disorder, and is often the first medication offered.

Thyroid Medication and Other Conditions

Thyroid hormones are foundational to other hormonal systems; thyroid hormone levels and medication can affect other conditions.

Addison’s Disease and Hypothyroidism

Addison’s disease, also called adrenal insufficiency, occurs when the adrenal glands don’t produce enough adrenal hormones, including cortisol. Addison’s disease can be autoimmune in nature. Autoimmune thyroid disease (Hashimoto’s) is the most common comorbidity of Addison’s, highlighting the link between adrenal and thyroid hormones.

Some symptoms of Addison’s disease and hypothyroidism overlap, including:

  • Fatigue
  • Appetite changes
  • Weight gain
  • Depression
  • Hair loss

Thyroid Pregnancy Issues

Thyroid hormone is critical during pregnancy as levels rise to support fetal growth and development.While it is possible to get pregnant with hypothyroidism, medication adjustments may be needed. If you take thyroid medication, check in with your doctor when you are trying to conceive to plan for medication adjustment once you confirm pregnancy.

In addition to thyroid changes during pregnancy, we must be aware of thyroid health during the postpartum period. When hormone levels drop postpartum, they can trigger changes in the thyroid and cause a flare of symptoms or new symptoms related to postpartum thyroiditis.

Can Hypothyroidism Cause Infertility?

Women with hypothyroidism can experience cycle irregularity. Untreated and unmanaged hypothyroidism can affect reproductive health and your ability to become and stay pregnant. Working to optimize thyroid health and find the correct medication and dosage helps regulate the menstrual cycle and support fertility.

For all the details about hypothyroidism and infertility, please read Can I Get Pregnant with Hypothyroidism?

Can Hyperthyroidism Cause Infertility?

Hyperthyroidism is a state of excessive thyroid hormone, which can be due to an autoimmune disorder, infection, or too high of a dose of thyroid hormone. When thyroid hormone levels are too high and can also affect fertility and menstrual cycles.

In hyperthyroid cases where the thyroid gland has been ablated or removed as treatment, patients will need to have adequate thyroid hormone replacement replace like someone with hypothyroidism.

Thyroid Issues Related to Fillers and Inactive Ingredients

Thyroid medications don’t only contain thyroid hormone; they also contain fillers and inactive ingredients that vary by medication and brand name. People with thyroid issues may be sensitive to specific ingredients, like corn, lactose, or starch (which could contain gluten).

Ask your doctor or pharmacist about all ingredients in a medication to see which option may be the best fit for you. You can also ask them to compound a product without any allergens.

Medication Monitoring and Follow-Up

Regular monitoring of thyroid labs and symptoms is essential when using thyroid medications to dial in the correct medication and dosage. Remember that you may need to adjust medication during hormonal transitions like pregnancy, postpartum, and menopause, during times of high stress, or when you change your diet and lifestyle.

Symptoms to Monitor for Optimal Thyroid Health

Symptoms of hypothyroidism and hyperthyroidism could indicate you need to adjust your thyroid replacement dosage or improve medication adherence. It is also important to monitor serum thyroid hormone levels. 

Hypothyroid symptoms include:

  • Weight gain or weight loss resistance
  • Constipation
  • Dry skin
  • Hair loss
  • Cold hands and feet; poor circulation
  • Fatigue
  • Menstrual irregularities
  • Mood changes
  • Fertility issues

Hyperthyroid symptoms include:

  • Weight loss
  • Increased appetite
  • Racing heart and palpitations
  • Anxiety and depression
  • Loose stools
  • Menstrual irregularities
  • Irritability
  • Goiter (enlarged thyroid)
  • Bulging or swollen eyes
  • Increased sweating

Side Effects of Thyroid Medications

Side effects of thyroid medications can include the hypo or hyperthyroid symptoms above when the medication dose needs to be adjusted. Side effects include allergic reactions, such as hives, swelling, and difficulty breathing.

In addition, each medication type and brand may have its own possible side effects. Please discuss side effects with your doctor or pharmacist so you can proceed with informed consent.

Frequency of Thyroid Function Testing

When you begin thyroid medication, have a full thyroid panel after 6 to 8 weeks to assess the medication’s effectiveness and adjust the dosage if needed. You may need more frequent testing as you dial in the correct medication and dosage.

When your thyroid is stable, you may need less frequent testing. I suggest at least annually and if you begin to experience the return of thyroid symptoms.

Importance of Regular Follow-Ups with Healthcare Providers

Taking thyroid medication requires more than a prescription. I can’t stress enough how important regular follow ups are. You will likely need to adjust what works for you as you get older and go through different life phases.

Lifelong Thyroid Medication or Temporary Use

Each person is unique, and thyroid medication needs to be tailored to their needs. Sometimes, people will need to take thyroid medication for their entire lives. For example, people with Hashimoto’s thyroiditis who’ve had significant thyroid gland destruction and can’t produce enough thyroid hormones may need long-term medication. Another example of lifelong use will be in people who’ve had all or part of their thyroid gland removed because of Graves’ disease or thyroid cancer.

Other people may benefit from temporary use of thyroid medication while they go through a life transition (such as postpartum) or during an acute thyroid episode. Temporary use may also be beneficial in Hashimoto’s or hypothyroidism while someone is working with their naturopathic doctor to address root causes. Sometimes, when lifestyle changes, diet changes, and supplements are optimal, medication can be reduced or discontinued.

How to Make Thyroid Medication Work Better

Thyroid medication isn't often enough to adequately address hypothyroidism and won't address the underlying cause if it is an autoimmune disorder.


Thyroid hormones will impact physical ability and activity. When thyroid hormones are low, it may be harder to have the energy for and tolerate exercise. When thyroid levels improve because of medication and other interventions, it’s time to move your body to get all the benefits of physical activity for your hormonal and metabolic health.

Decrease Inflammation

Inflammation is a primary factor that affects thyroid health and thyroid hormone conversion. In addition to eating an anti-inflammatory diet, ensure you eat adequate omega-3 fats from cold water fish and fish oil supplements.

Omega Plus provides 1500mg of anti-inflammatory omega-3 fats along with lipase for improved digestion and absorption. Omega Plus is also part of the Thyroid Support Kit.

I’ve created a free anti-inflammatory recipe guide to help improve thyroid function.

Manage Stress

Stress affects thyroid levels and makes T4 to T3 conversion more challenging, which can translate to a slower metabolism and more hypothyroid symptoms. Find the tools that work for you to manage your stress for balanced hormones. Some ideas include yoga, meditation, nervous system retraining, breathing exercises, journaling, therapy, and more.

Nutrients for Thyroid Support

As mentioned above, thyroid health and function require a lot of nutrition. For example, we already know about the importance of iodine and selenium. Still, total thyroid health relies on an abundance of trace elements in the diet, including zinc, manganese, magnesium, copper, and chromium.

Nutrients for Thyroid Hormone Production:

  • Iron
  • Iodine
  • Vitamin C
  • Vitamin D
  • Vitamin B2
  • Vitamin B3
  • Vitamin B6
  • Selenium
  • Zinc
  • Tyrosine

Nutrients for Conversion T4 to T3:

  • Selenium
  • Zinc

Nutrients for Thyroid Hormone Utilization by Cells:

  • Zinc
  • Vitamin A

You’ll find complete thyroid-supportive nutrients in my Thyroid Support Kit. This kit includes the three most often recommended supplements to support thyroid health. It includes:

  • Thyroid Support – This complete thyroid health formula contains the essential nutrients to support thyroid hormone production and function throughout the body. It includes vitamin A, vitamin B2, iodine, zinc, selenium, copper, manganese, chromium, and tyrosine.
  • Adrenal Support – This supplement supports adrenal health to help mitigate the effects of stress on the thyroid and includes micronutrients and adaptogenic herbs. Adrenal support is essential for thyroid health and healing.
  • Omega Plus – This concentrated omega-3 formula helps balance inflammation and support thyroid function.

For dietary support of thyroid health, read the top 10 foods for thyroid health and check out this one day meal plan.

Follow Best Practices

It is important to always follow best practices when taking your medication. Prioritize taking your medication daily, at the same time, and separating medication from food and supplements that inhibit absorption.

Thyroid Medication Summary

Thyroid hormones affect every cell in the body and overall health. In cases where thyroid medication is indicated, it is absolutely necessary for health, and there are many options to discuss with your healthcare provider. I encourage you to make informed decisions with medical guidance to find the best medication strategy to meet your needs.

In addition to medication, nutrition, lifestyle, and supplement strategies offer your body additional support. You can use medication and work on lifestyle changes concurrently, and both can help you to feel your best.

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About The Author

Dr. Jolene Brighten

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Dr. Jolene Brighten, NMD, is a women’s hormone expert and prominent leader in women’s medicine. As a licensed naturopathic physician who is board certified in naturopathic endocrinology, she takes an integrative approach in her clinical practice. A fierce patient advocate and completely dedicated to uncovering the root cause of hormonal imbalances, Dr. Brighten empowers women worldwide to take control of their health and their hormones. She is the best selling author of Beyond the Pill and Healing Your Body Naturally After Childbirth. Dr. Brighten is an international speaker, clinical educator, medical advisor within the tech community, and considered a leading authority on women’s health. She is a member of the MindBodyGreen Collective and a faculty member for the American Academy of Anti Aging Medicine. Her work has been featured in the New York Post, Forbes, Cosmopolitan, Huffington Post, Bustle, The Guardian, Sports Illustrated, Elle, and ABC News. Read more about me here.