Ask Your Levothyroxine Question!

What does "optimal" treatment mean for hypothyroidism versus "normal" levels?  (Kelly R.)

Optimal treatment means that your hypothyroidism medication is safely helping to resolve your symptoms as best as possible. It's not enough to have a Thyroid Stimulating Hormone (TSH) level that's in the normal reference range (usually .5 to 5). You may need a TSH level that's "optimal," usually below 2.5. AND, your treatment needs to provide relief from hypothyroidism symptoms, which can include fatigue, weight gain, depression, anxiety, brain fog, constipation, and many other commonly-seen complaints.

What's the best way to take my levothyroxine? (Marcella S.) 

Ideally, you should take your levothyroxine in the morning, at least an hour before eating, drinking coffee, drinking milk, or taking supplements that contain iron, calcium, or magnesium. When it comes to calcium, iron, and magnesium, it's best to take it at least three to four hours apart from your levothyroxine. Also, be careful to avoid calcium-fortified juices within three to four hours of your medication. 

How can the extra ingredients in levothyroxine tablets affect my hypothyroidism treatment? (Bob G.) 

If you are taking Synthroid®, Levoxyl®, Unithroid®, or generic levothyroxine tablets, you should be aware that your tablets contain a variety of extra ingredients, known as excipients. They are used as fillers, binders, coatings, and dyes in the tablets. 

Excipients can include: 

  • Acacia -- derived from tree bark, and a known trigger for seasonal allergies

  • Povidone iodine -- an ingredient that's problematic for people with iodine allergies

  • Lactose -- which can cause symptoms in people with lactose intolerance

  • Starch -- which can contain gluten, an issue for people with gluten sensitivity or celiac disease

  • Dyes -- which some people are sensitive or allergic to and can cause symptoms and reactions

If you have allergies or sensitivities to these extra ingredients, you may have side effects from your levothyroxine tablets, or they may not work well for you. 

For more details on excipients, dyes, and extra ingredients, see Part 1 of the Levothyroxine Deep Dive

My doctor says that all levothyroxine drugs are the same, and it doesn't matter which one I take. Is that true? (Pablo A.) 


All levothyroxine drugs are not the same. Here's the rundown. 

Levothyroxine comes in three forms: tablets (Synthroid®, Levoxyl®, Unithroid®, and generic tablets), gel caps with liquid levothyroxine (Tirosint®), and liquid oral solution (Tirosint®-SOL). 

Among the tablets, different fillers, binders and dyes (excipients) mean that some tablet formulations may cause sensitivity in some people taking them. In addition, because levothyroxine potency can vary -- FDA regulations require it to fall within 95 to 105% of the stated potency -- even the same dosage of levothyroxine can have different potency, depending on which company makes it. Also, the liquid forms of levothyroxine – Tirosint capsules, and Tirosint-SOL oral solution – are shown in research to be better absorbed by people with allergies, sensitivities, or digestive and absorption problems. Bottom line: All levothyroxine drugs are not the same. 

For more details on excipients and potency, see Part 1 of the Levothyroxine Deep Dive


What is Tirosint® and Tirosint-SOL®, and why is the list price so much higher than other brands of levothyroxine? (Linda B.)


Tirosint® and Tirosint®-SOL are special forms of levothyroxine. Tirosint® is liquid levothyroxine, in a gel capsule. Tirosint®-SOL is straight liquid levothyroxine, taken as an oral solution from individually-dosed ampules.


Because they have no dyes, and very few excipients, the Tirosint forms of levothyroxine were initially recommended for people with allergies and sensitivities. Also, research has shown that Tirosint® and Tirosint®-SOL are better absorbed by people with digestive and intestinal issues, including Irritable Bowel Disease/Syndrome (IBD/IBS), Crohn's disease, ulcers, and other conditions that cause absorption problems. More recent research has now shown that the Tirosint® and Tirosint®-SOL forms of levothyroxine are better absorbed in general, and as a result, more patients have switched to these treatments, and more doctors are recommending it.


The list price of Tirosint® and Tirosint®-SOL is over $100 a month, and due to interference by pharmacy benefit managers, many patients have an insurance copay of $60 to $100 or more per month. IBSA, the manufacturer, has created two programs to ensure that any patient who can benefit from Tirosint® or Tirosint®-SOL can afford the medication.

For those with insurance, the Tirosint® copay savings program discounts your copay, and with insurance, almost all patients pay no more than a $25 a month copay. For those without insurance, or with minimal prescription drug coverage, the Tirosint® Direct program allows you to fill your prescription by mail order from designated pharmacies, and pay $50 a month, or $120 for a three-month supply. 


For more information on the costs of Tirosint® and other levothyroxine drugs, see Part 2 of the Levothyroxine Deep Dive.


The Levothyroxine Deep Dive program is copyright © 2020, Mary Shomon. All rights reserved.

Levoxyl®, Synthroid®, Tirosint®, Tirosint-SOL®, and Unithroid® are registered trademarks. Product images and logos used with permission. 


Mary Shomon does not provide medical advice, diagnosis or treatment.


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If you think you may have a medical emergency, call your doctor or 911 immediately. Mary Shomon does not recommend or endorse any specific tests, physicians, products, procedures, opinions, or other information that may be mentioned. Reliance on any information provided by Mary Shomon is solely at your own risk.