desiccated thyroid

Updated March 2019

Recently I’ve been getting a ton of questions about desiccated thyroid from my thyroid patients and as Naturopathic Doctors have recently gained access to the prescribing of this medication, it’s a great time to do some Q&A.

So, here are the top 5 things you need to know about Natural Desiccated Thyroid (NDT)

1. What is desiccated thyroid? (NDT)
NDT is used for the treatment of low thyroid function and hypothyroidism. It’s considered a more natural form of thyroid medication and is sourced from porcine (pig) thyroid glands. NDT is NOT the same as natural thyroid “extracts” (the ones found online and in some health food stores – these should be avoided!). NDT can be used in place of synthetic thyroid medications such as levothyroxine (T4) or cytomel (T3).

2. What is the difference between NDT and levothyroxine (Synthroid)?
Synthroid is the synthetic version of T4 which is only one of our thyroid hormones. NDT is sourced from actual thyroid glands and contains the full spectrum of thyroid hormones including T4 and T3 (which is our most metabolically active thyroid hormone). Many of the benefits of NDT come from the addition of the T3 hormone.

3. Where can I get desiccated thyroid?
NDT is available at most pharmacies by prescription only through your medical doctor or Naturopathic Doctor. In the US, desiccated thyroid is also called armour thyroid or nature thyroid. In Canada, there are 2 sources of desiccated thyroid, ERFA Thyroid and Compounded Desiccated Thyroid. ERFA thyroid is produced in 30mg, 60mg, and 125mg tablets, is available at almost any pharmacy, and is considered the ‘generic’ form. Compounded desiccated thyroid is produced by Medisca and is only available through compounding pharmacies. It is a powdered form that can be made into any dosage and is prescribed in capsule form.

So what form is best? 
I use primarily compounded desiccated thyroid in my practice. This form has less fillers (like cornstarch) that are found in the generic brand. As well, Medisca provides a certificate of analysis with each produced batch, so I can guarantee my patients that they are getting a standardized and consistent dose. It also gives us dosing flexibility, so we can get creative and really fine tune doses if (for example) a patient needed 77.5mg of NDT – no problem!

4. My doctor says desiccated thyroid isn’t safe, is that true?
Historically there have been concerns about NDT doses not being standardized, meaning that one pill could have different amounts of hormone than the next. Because the thyroid gland is so sensitive to changes, this is definitely a serious concern. However, NDT is currently produced by only 2 manufacturers in Canada and like any other pharmaceutical, it has a drug identification number (DIN) which means that it has been reviewed and approved by Health Canada. This also allows for quality control, inspections, and all the other regulations that go along with any pharmaceutical drug. As stated above, I monitor each ‘batch’ of compounded NDT to ensure my patients are getting the same standardized dosing.

5. Is desiccated thyroid better than Synthroid?
Well, it all depends on the person and their current state of health. Many people do feel better on NDT due to the addition of T3, our most active thyroid hormone. Others hypothesize that NDT is superior because it also contains two other lesser known thyroid hormones (T1 and T2). Unfortunately, quality research comparing NDT and other forms of T4 and T4/T3 combination medications is limited. A 2013 study compared levothyroxine to NDT and found that 49% preferred desiccated thyroid, 19% preferred levothyroxine, and 23% found no difference.

What I see in practice
After years of prescribing and working with desiccated thyroid, the vast majority of my patients feel superior on NDT. Improvements in energy, body temperature, hair growth, sleep, skin, mood, metabolism, and more have all been reported. Most of my patients notice a difference in as little as 1-2 weeks, and symptoms continue to improve over the course of 3-6 months while we finesse their dose.

Have more NDT questions? Book a free thyroid assessment with me here

– Your Thyroid ND
Dr. Katie Rothwell, ND

Decode your Thyroid! Get your free guide to optimal thyroid hormones herePBOOK008


Hoang TD et al Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism: A randomized, double-blind, crossover study. J Clin Endo Metab 2013;98:1982-90. Epub March 28, 2013.

ERFA Pharmaceuticals