Are You Prescribing the Wrong Thyroid Medication?

by Dr. Kate Whimster ND | Follow on Twitter

Did you know that Synthroid is the MOST prescribed drug in Canada?

THYROID DYSFUNCTION, particularly hypothyroidism, is incredibly common, yet poorly understood and hardly discussed.

Your thyroid, that little butterfly-shaped gland at the base of your throat, plays a role in metabolism, fertility, hormone balance, mood, digestion, temperature regulation, heart health, and many more important systems.

So, shouldn’t we pay a little bit more attention to how we treat it?

This article is about the surprisingly few medications available to treat underactive thyroid (aka hypothyroidism) as well as how to optimize treatment whether you are taking thyroid medication or not.  Learn more background information on decoding thyroid testing.

Levothyroxine: the leading lady

Levothyroxine, also known as Synthroid, Eltroxin, and some other trade names, is first line conventional medical therapy for hypothyroidism and the most prescribed medication in Canada.

Levothyroxine provides synthetic T4 (thyroxine), the primary hormone produced by the thyroid gland.  T4 is the precursor to T3 (triiodothyronine) and is converted to T3 by tissues throughout the body.  T3 (as well as several other thyroid hormones) is also produced by the thyroid gland, but in lesser amounts that T4.

Supplementing only T4 provides the initial hormone to be converted and thus depends on conversion to have effect at the tissue level.  This also provides feedback to the pituitary gland which produces TSH, thus bringing down elevated TSH found in hypothyroidism.

The correct dose of T4 can normalize TSH levels but may not resolve symptoms of hypothyroidism or resolve the autoimmune process present in Hashimoto’s hypothyroid.

Hashimoto’s hypothyroid happens to be the most most common cause of hypothyroidism, so while levothyroxine normalizes some lab values, it does not address the cause of Hashimoto’s hypothyroid.

Given how common underactive thyroid is, it’s highly likely that you or someone you know is using this medication.  Many of my patients taking levothyroxine have varying results, from greatly reducing symptoms to noticing no change at all compared to taking no medication.

There are several brands of levothyroxine, and changing brands can significantly affect results and appropriate dosing.  I can’t tell you how many times I’ve had patients switch from branded to generic medication (or vice versa) and notice major differences in symptoms and/or adverse effects, not just with thyroid medications.

Before bed dosing is superior!

Patients are nearly always instructed to take levothyroxine in the morning, but in 2007 group of Dutch researchers completed a pilot study (only 12 patients) demonstrated that

“l-thyroxine taken at bedtime by patients with primary hypothyroidism is associated with higher thyroid hormone concentrations and lower TSH concentrations compared to the same l-thyroxine dose taken in the morning.” (1)

They followed up this study with a larger, double-blinded, placebo controlled crossover study that yielded the same results:

“Levothyroxine taken at bedtime significantly improved thyroid hormone levels. Quality-of-life variables and plasma lipid levels showed no significant changes with bedtime vs morning intake. Clinicians should consider prescribing levothyroxine intake at bedtime.” (2)

For those patients taking levothyroxine, consider a change in timing of medication, and ensure you follow up with appropriate testing to ensure the right dose is being prescribed.

Liothyronine: the forgotten middle child

Liothyronine, also known as Cytomel, is a much less common medication used to treat hypothyroidism.  It provides synthetic (triiodothyronine) directly rather than via conversion from T4.

Supplementing T3 has a more direct effect at the tissue level and can normalize TSH levels.  This medication is often used in combination with T4 but this combo does not seem to provide better results that T4-only therapy, so it is not very common.

It is rare that I see patients taking this medication as it is not the typical first-line therapy for hypothyroidism.

Desiccated thyroid: the rising star

Known simply as Thyroid (made by Erfa) in Canada and under several brands available in the United States, dessicated thyroid is the powdered thyroid gland of pigs, providing T4 and T3 as well as additional hormones produced by the thyroid gland (T2, T1, calcitonin).

What’s old is new again!

Desiccated thyroid at one point was the ONLY medication option for underactive thyroid and has been around the longest.

Because it is made from the whole gland, desiccated thyroid is considered a more complete product, providing supplementation of thyroid hormones closest to what would be produced naturally.

Many patients choose this medication after starting with levothyroxine because they prefer a natural product and experience better results in symptom reduction.

Because desiccated thyroid is NOT synthetic and is derived from a natural source that will vary from batch to batch, it is very important to use a reputable brand that is standardized and formulated carefully.

In the United States particularly, there are a lot of products with desiccated thyroid in them, some of which are not standardized and pose a major health risk.

How to maximize thyroid medication

Hypothyroidism is nearly never JUST about the thyroid gland.  Remember how your thyroid is interconnected with so many other systems in your body?  For optimal thyroid health, you must support other key systems:

Immune balance is key

Most hypothyroidism is autoimmune in nature (Hashimoto’s hypothyroid).  In these cases, the immune system is mistakenly damaging the thyroid gland by creating antibodies against it, which impairs thyroid function.

Optimal treatment must include immune support and reduction of this autoimmune process to preserve long-term thyroid function.

Harmonize hormones

It is common in my practice to see hypothyroidism preceded by years of female hormone imbalance (PMS symptoms, painful periods, irregular periods, fertility challenges, etc).  Many of these hormonal issues are caused by excess estrogen stimulation and estrogen also happens to reduce the efficiency of T4, the major hormone produced by the thyroid gland.

Addressing hormone balance not only prevents many chronic diseases but also improve thyroid function and reduces need for medication.

Stress less for better adrenal function

There is lots of talk about adrenal glands these days.  Who knew that those little pyramid-like glands that sit on top of your kidneys would ever be so popular?  These little glands are actually powerhouses, producing all kinds of neurotransmitters and hormones that are essential for normal function.

But what most people are interested in is their production of cortisol, the major stress hormone.  Did you know that cortisol decreases T3, the more active thyroid hormone, increases auto-antibody production (the root cause of Hashimoto’s hypothyroid), and interferes with function of the thyroid gland?

Chronic stress means you are constantly flooding your body with cortisol, impeding thyroid function as well as setting you up for lots more disease down the road.  In fact, many hypothyroid symptoms (such as fatigue, depression, low libido, poor memory, weight gain) can ALSO be attributed to poor adrenal function as a result of chronic stress.

Supporting the adrenal glands and reducing stress is therefore a necessary part of any thyroid treatment and can improve the efficacy of medication.

What else can I do?

For more tips on improving thyroid function naturally, check out my article 10 tips for thyroid balance.


  1. Bolk N, Visser TJ, Kalsbeek A, van Domburg RT, Berghout A. Effects of evening vs morning thyroxine ingestion on serum thyroid hormone profiles in hypothyroid patients. Clin Endocrinol (Oxf). 2007 Jan;66(1):43-8.
  2. Bolk N, Visser TJ, Nijman J, Jongste IJ, Tijssen JG, Berghout A. Effects of evening vs morning levothyroxine intake: a randomized double-blind crossover trial. Arch Intern Med. 2010 Dec 13;170(22):1996-2003.
About the Author
Dr. Kate Whimster ND

Dr. Kate has been featured on CBC Metro Morning, CP24, Toronto Star, Elle Canada, Reader’s Digest Canada, and NOW Magazine and has a special interest in: • Women’s health at any age (menses to menopause!) • Naturopathic gynecology (including HPV, candida, STIs) • Thyroid balance • Digestive health • Healthy detoxification Patients seek out Dr. Kate as a tenacious problem-solver who takes a thorough and organized approach to long-term healing. Dr. Kate also teaches Naturopathic Gynecology at the Canadian College of Naturopathic Medicine. Check out Dr. Kate’s blog and sign up to receive exclusive articles and free wellness guides.