New Study Shows Natural Thyroid is Better

New Study Shows Natural Thyroid Better than Synthetic

by Jeffrey Dach MD

Left image: Man with Hypothyroidism. Left Panel  is before treatment, and Right Panel is after treatment with natural thyroid pills NDT natural desiccated thyroid Photos taken from and courtesy of Mark Starr MD’s book, entitled  Hypothyroidism Type 2: The Epidemic.

American Thyroid Association (ATA) Guidelines

Natural Thyroid has been used successfully for more than 100 years (3), and it is blatantly obvious to any experienced clinician that natural desiccated thyroid is superior to T4-only medications such as Synthroid and Levothyroxine.  However, in spite its obvious clinical superiority, Endocrinology Societies such as the ATA have published guidelines advising doctors to stay away from natural thyroid. (1)   Over the years, they have used a variety of reasons.  The latest reason is that there are no controlled trials .  Here is the quote from the ATA Guidelines:

As of 2012 there are no controlled trials supporting the preferred use of desiccated thyroid hormone over synthetic L-thyroxine in the treatment of hypothyroidism or any other thyroid disease.”(1)

A New Controlled Trial Comparing Natural Thyroid to Synthroid

This has changed, as a new controlled trial was just published in the May 2013 Journal of Endocrinology by endocrinologists at the Walter Reed National Military Medical Center in Bethesda, Maryland  (2)

Left image: natural thyroid comes from a pig thyroid gland.
Switching OVER to Synthroid

When a new patient comes into the Walter Reed Medical Center on natural thyroid, they are immediately switched over to Synthroid (or T4- only meds).

Occasionally DID NOT Feel As Well

The authors’ usual practice is to switch any new patient over from natural thyroid to Synthroid (T4-only levothyroxine).  However, the doctors noted that after doing Technesium 99M Radionuclide Scan of Throid Glandthis:

“Patients on natural thyroid (desiccated thyroid extract ,DTE), after being switched over to levothyroxine (l-T4), occasionally did not feel as well , (despite adequate dosing based on serum TSH levels.) “(2).

This is exactly what I have found in actual clinical practice over the years.  Patients feel much better on natural thyroid.  We use exclusively Nature-throid from RLC labs with good results.

Left Image: radionuclide scan of thyroid gland.

Comparing Synthroid to Natural Thyroid

Their controlled study compared natural thyroid with Synthroid.  What they found was that roughly half of the patients (48%) felt better on the natural thyroid, one third had no preference, and one fifth (18.6%) felt better on the Synthroid.  Clearly  the natural thyroid wins the comparison test (48.6% vs. 18.6%).

Ultrasound Image of Thyroid GLand“At the end of the study, 34 patients (48.6%) preferred Dessicated (Natural Thyroid), 13 (18.6%) preferred Levothyroxine (T4), and 23 (32.9%) had no preference.”(2)

Left image: Ultrasound image of thyroid gland.

Now that we have a controlled trial showing the natural thyroid is better, maybe the ATA should change its guideline? 

Update 2014:   New study shows that T4-only Levothyroxine cannot guarantee normal thyroid function in all patients, even with a TSH in the “normal range”. Quote: “More than 20% of these patients, despite normal TSH levels, do not maintain FT3 or FT4 values in the reference range, reflecting the inadequacy of peripheral deiodination to compensate for the absent T3 secretion.”

Gullo, Damiano et al. “Levothyroxine Monotherapy Cannot Guarantee Euthyroidism in All Athyreotic Patients.” Ed. Marian Ludgate. PLoS ONE 6.8 (2011): e22552. PMC. Web. 23 Dec. 2014.

Articles with Related Interest:

Why Natural Thyroid is Better Than Synthetic

TSH Wars Part One

TSH Wars Part Two

Author: Jeffrey Dach MD

Finanical Dislosure: The author, jeffrey dach md,  receives no compensation from RLC labs nor from any other thyroid medication manufacturer.

Links and References:

1) ATA_AACE_Guidelines_Hypothyroidism_2012_natural_thyroid
Garber, Jeffrey R., et al. “Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association.” Endocrine Practice 18.6 (2012): 988-1028.

“Thus, there are no controlled trials supporting the preferred use of desiccated thyroid hormone over synthetic L-thyroxine in the treatment of hypothyroidism or any other thyroid disease.”


J Clin Endocrinol Metab. 2013 May;98(5):1982-90.ENDOCRINE CARE ,
Desiccated Thyroid Extract Compared With Levothyroxine in the Treatment of Hypothyroidism: A Randomized, Double-Blind, Crossover Study
Thanh D. Hoang, Cara H. Olsen, Vinh Q. Mai, Patrick W. Clyde and Mohamed K. M. Shakir – Author Affiliations Department of Endocrinology (T.D.H., V.Q.M., P.W.C., M.K.M.S.), Walter Reed National Military Medical Center, Bethesda, Maryland 20889; and Department of Preventive Medicine and Biometrics (C.H.O.), Uniformed Services University of Health Sciences, Bethesda, Maryland 20814

Context: Patients previously treated with desiccated thyroid extract (DTE), when being switched to levothyroxine (L-T4), occasionally did not feel as well despite adequate dosing based on serum TSH levels.

Objective: Our objective was to investigate the effectiveness of DTE compared with L-T4 in hypothyroid patients.

Design and Setting: We conducted a randomized, double-blind, crossover study at a tertiary care center.

Patients: Patients (n = 70, age 18–65 years) diagnosed with primary hypothyroidism on a stable dose of L-T4 for 6 months were included in the study.

Intervention: Patients were randomized to either DTE or L-T4 for 16 weeks and then crossed over for the same duration.

Outcome Measures: Biochemical and neurocognitive tests at baseline and at the end of each treatment period were evaluated.

Results: There were no differences in symptoms and neurocognitive measurements between the 2 therapies. Patients lost 3 lb on DTE treatment (172.9 ± 36.4 lb vs 175.7 ± 37.7 lb, P < .001).

At the end of the study, 34 patients (48.6%) preferred DTE, 13 (18.6%) preferred L-T4, and 23 (32.9%) had no preference. In the subgroup analyses, those patients who preferred DTE lost 4 lb during the DTE treatment, and their subjective symptoms were significantly better while taking DTE as measured by the general health questionnaire-12 and thyroid symptom questionnaire (P < .001 for both). Five variables were predictors of preference for DTE.

Conclusion: DTE therapy did not result in a significant improvement in quality of life; however, DTE caused modest weight loss and nearly half (48.6%) of the study patients expressed preference for DTE over L-T4. DTE therapy may be relevant for some hypothyroid patients.

J R Soc Med March 1, 2011 vol. 104 no. 3 100-106
The discovery of thyroid replacement therapy. Part 3: A complete transformation   Stefan Slater   Edinburgh EH4 6PD, UK
The idea of thyroid replacement therapy


Author: Jeffrey Dach MD
7450 Griffin Road, Suite 190
Davie, Fl 33314

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  1. Richard Snouffer, MD June 19, 2013 at 10:55 PM

    The marked superiority of Armour Thyroid to Synthroid was clearly demonstrated in a crossover study published in the New England Journal of Medicine at least as far back as 1999. The results were beyond question. Yet we never hear of it.

    Well, MY patients hear of it–especially those who come to me already on Synthroid–usually shortly before they FEEL the difference.

    Richard Snouffer, MD
    The Carlton Clinic

  2. vic February 1, 2014 at 2:46 PM

    If Armour is supposed to be good, why is it that when I take it I can’t sleep.
    On the other hand, I sleep good with L- TYROXINE, but I am getting leg cramps.

    • Jeffrey Dach MD February 2, 2014 at 8:16 AM

      Hi Vic,

      The Armour formulation was changed a few years ago, and most people have moved on to RLC labs. Hope this helps.

      dr d

  3. Jude Hartman February 3, 2014 at 3:39 PM

    Hi Dr. D.
    I had my thyroid removed due to papillary thyroid carcinoma 2 years ago. I am 56 years old. I take 1.5 grain nature-throid every morning and have done well except for some fatigue. I am wondering if I should be doing or taking anything additional or different from what you would normally recommend for someone who is hypothyroid. I would really like to understand how I am different from those who are just hypothyroid. I’ve tried researching this and have not been able to come up with much. Your site has been most helpful. Additionally, I will be in Africa for 9 months this year on a mission. Other than taking my nature-throid and bio-identical hormones (E2-1.25; prog-150; test-2.5) is there anything else I should be considering? I supplement with VitD3, Omega 3, and VitC. I am planning on taking the yellow fever vaccine, but nothing else, should I reconsider and take additional vaccines and is it okay to get them all at the same time?
    Thank you so much for taking time out of your busy schedule to reply.

    • Jeffrey Dach MD February 4, 2014 at 6:24 AM

      Hi Jude

      I am glad you are doing so well on the Natural thyroid.

      Sometimes it takes time to find the right dosage which will relieve all symptoms completely.

      Thanks for sharing your comment.


      dr d

  4. Barb September 5, 2014 at 8:55 PM

    So, for those of us who have permanent damage from T4-only and mostly-T4 meds (who can only convert T4 into RT3), where are the comparisons of “natural” vs. Cytomel only? (To my knowledge, there are none; and there are very few doctors who understand the importance of a T3-only med for us, even though there are, literally, millions of us.) What, exactly, does being able to convert T4 into FT3 do for a thyroidLESS person? Would my temp be closer to normal? Would I produce enoug stomach acids to digest food properly? Would I have “normal” red blood cells, carrying enough oxygen to eliminate my air hunger?

    I understood that calcitonin opposes PTH. In other words, PTH says, “Let’s make calcium” and calcitonin says, “Ok, but not too much”. My paras survived my RAI, and they adjusted to not having any calcitonin to oppose them. I’m grateful, given the horror stories I’ve heard from others. If paras are removed during surgery, why would someone need calcitonin to oppose calcium they are ingesting instead of secreting?

    Info provided by researchers who want to maintain their jobs through annonymity makes clear that prescription NDTs are made, in the USA, exclusively, from pigs, and the pigs are ingesting, exclusively, GMO feed. Otherwise, demand would rapidly outpace supply. GMOs are known endocrine disruptors. What about those of us who are thyroidless, with “thyroid” antibodies (autoimmune disease), who know that anything porcine ingested will cause a spike in those antibodies? What about people who are allergic to all things porcine? What about people who practice the Jewish faith? What about doctors who practice the Jewish faith and won’t prescribe anything porcine? There are OTC NDTs, made from range fed cows, but cows have four stomachs and we humans only have one. OTC NDTs don’t contain prescription strength hormones, so that much more has to be ingested to obtain replacement. When you’re thyroidless, supplementation = neglect, just like when we are confined to a T4-only med.

    The generic Cytomel didn’t work for me. T3 from a compounding pharmacist didn’t work for me. Cytomel DOES work. It’s so short acting that I can better anticipate my need for an extra dose, and I know when I can skip a dose, or delay it longer than I might otherwise. Thyroidless women’s hormones fluctuate so much more, and so much more frequently than men’s, and our T3 needs to fluctuate with them. Cytomel allows that fluctuation. I wish it didn’t get such a bad reputation from supposedly open-minded doctors….

    Bottom line: healthy thyroids are EXQUISITELY self-regulating, and every human being is unique. Women are even more unique than men because of our “complicated” hormones. If a doctor doesn’t understand how a healthy thyroid works for an ovulating woman, then a doctor can’t expect to be that ovulating thyroidless woman’s thyroid FOR her, from the outside in, via a prescription for ANY med(s). The woman has to know her body well enough to provide this EXQUISITENESS herself, from the outside in, with the right dose of the right med at the right time. I’m still in awe of the men who think they can be my thyroid for me from the outside in with a med that I can’t convert into FT3, or one that I can’t ingest without causing a spike in antibodies! LOL :-D

    Thanks for your articles.

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