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Mary Shomon

Attention Thyroid Patients: Is There Gluten in Your Synthroid?

By July 6, 2009

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A reader Cathy wrote to share some thoughts about Synthroid's fillers and ingredients. "Hay fever and lactose intolerance are not the only conditions that may be adversely affected by Synthroid. I have been recently diagnosed with celiac disease and must be on a strict gluten-free diet. In my research of gluten-free drugs, both prescribed and over-the-counter, I was surprised to learn that Abbott Pharmaceuticals cannot guarantee the gluten-free status of Synthroid because they do not test the additives they put into the drug for gluten. My doctor does not want to change my medication as I've been taking Synthroid and doing well on it for over 8 years. I have been gluten-free for 8 months and feel fantastic - better than I've felt in a long time - but it really aggravates me that Abbott can't be bothered to test for the gluten."

This is unfortunate, given the established link between celiac disease/gluten intolerance, and autoimmune thyroid disease. Come on Abbott...get with the program!

For more information on the link between celiac disease and thyroid problems, read: The Celiac/Autoimmune Thyroid Connection.

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July 6, 2009 at 2:06 pm
(1) Anne says:

I too am disturbed that Abbott will not test for residual gluten in Synthroid. I tried a generic and my TSH started to rise to an unacceptable level. I am now back on Synthroid to see if my TSH drops back to where it was.

August 16, 2011 at 10:52 am
(2) Beth says:

Abbott says they do not test the final product. But they have polled all the venders for the ingredients in their synthroid. Only 1 vender did not respond and that was for one of the dyes in the medication. All other venders claim to not have gluten in their ingredients.

July 6, 2009 at 3:22 pm
(3) PB says:

After my recent labs, my Endo upped me from Synthroid 112 to 125. From the first day of taking the 125 my stomach began cramping and I was nauseated.

After a full week of discomfort I contacted my Endo who put me back on the 112 except that I now take two pills on Sundays. After research by my Pharmacist it was found that the 112 has two dyes in it while the 125 has six dyes. Seems I am allergic to one or more of the dyes in the 125′s.

Unfortunately the reaction also set off a nasty bout of IBS and Diverticulitis, of which I have had to be on antibiotics for and may need surgery.

There are many people who have allergies and sensitivities, so why shouldn’t drug companies be required to disclose everything that is in our meds?

July 7, 2009 at 8:12 am
(4) Michael Thorn, RN says:

I am on Synthroid as well. Just because they don’t test doesn’t mean that there is gluten in a product. If the ingredients are non-gluten then there is really no reason to be concerned.
I certainly agree that all drugs should list their ingredients.

July 8, 2009 at 11:43 am
(5) elayne says:


my sister has uncontrolled throid disease. however,she does not have a computer. could you please send her valuable information?

adele kalfon
259-04 148 drive
rosedale ny 11422

July 8, 2009 at 9:38 pm
(6) JOCELYN says:

I recently wrote to RLC labs asking about any gluten contentin their thyroid meds. RLC makes and distributes Nature-throid.(A natural dessicated porcine thyroid med very similar to the old Armour thyroid). RLC Labs told me that Nature-throid is gluten-free and that the facility that produces it is gluten-free. I hope this is helpful for any gluten sensitive thyroid patients.


July 11, 2009 at 9:36 am
(7) Joyce says:

I could not understand why on sythroid why I had diarreha ( spelling) everyday for a year… here it is what they put into the meds… I can not have dairy products and this was the problem with the meds… I did not put 2+2 together until I looked it up one day on here… now that I’m off it is not as bad… now instead of having 5 bouts aday.. I’m down to maybe 2

July 11, 2009 at 10:25 am
(8) Leigh says:

I am really glad to see this issue coming to attention. Having Celiac I have been asking this question for a while but wondering why the drug companies aren’t making more hypoallergenic thyroid medications? Upon diagnosis, lots of Celiacs also have a lactose intolerance, many have developed other allergies (such as to corn) prior to their diagnosis and it seems a no brainer – given the medical ‘association’ between celiac and hashimotos – to have more options like the 50 mcg of Levoxyl with a cellulose filler.

In general, if you look at a proprietary listing of the ingredients of many meds, the insensitivity of the drug companies formulating non-hypoallergenic medications for a variety of conditions – even if the ingredients are in supposedly miniscule amounts – doesn’t seem to be in the best interests of creating healthier people. This has been a frustration of mine for some time.

January 18, 2010 at 9:05 am
(9) Teresa Spade says:

Have you been tested for Hashimotos? If you are eliminating gluten from your diet, there is a very real danger that you may overdose on your thyroid medicine. This is because the truth is, you are allergic to gluten. Thats all Hashimotos is. When you remove gluten, your body will heal.

March 10, 2010 at 7:34 pm
(10) Nina says:

I don’t think that’s quite true, Teresa. I’ve been on a gluten free diet for 1 1/2 years and my thyroid has not improved at all. It basically shut down operation completely. Maybe someone who still has a functioning thyroid (only sluggish) might be able to improve thyroid function by beginning a celiacs diet, but there is no guarantee for it or for how long it lasts until the body starts attacking it again.

March 12, 2010 at 6:23 am
(11) Faith says:

I have been Hashi’s for 10 years. It has been a long dark road. I now see only a Naturopath who has diagnosed my food intolerances, and after only 3 weeks of being off the foods I am allergic to,my antibodies are gone, and my free t3 is higher than it has been in years without a meds dosage change.
I believe the wheat/gluten intolerance is the answer, which of course a regular Dr will never tell you, that is provided they are even aware of it.

March 14, 2011 at 4:48 pm
(12) Mom of # GF says:

It infuriates me as well that Abbot Labs cannot be bothered to test and have no qualms telling consumers that.

March 28, 2011 at 7:45 pm
(13) Teri Meek says:

15 years dealing with Hashi. My nutritionist has me on strict gluten free, sugar free, nut free, eating plan that has worked wonders on me. Synthroid lowered to 88 mcg. Remove foods from your diet that have reputation for allergic reactions. Get the bad yeast under control and add probiotics. It’s all connected…the immune responses and the symptoms!

June 29, 2011 at 11:35 am
(14) Beth says:

I am curious how you are doing on this diet and am curious why your nutritionist put you on a nut free plan. I am celiac with a low thyroid and have not been able to lose weight so am willing to try anything.

September 9, 2012 at 10:22 pm
(15) Michael says:

It’s unfortunate that people who call themselves patient advocates spread false information that could be harmful to others. Check your facts Mary. There are not any ingredients in Synthroid that could possibly even contain gluten. Patients reading this article could be mislead and unnecessarily stop or change their medication.

November 12, 2012 at 9:14 am
(16) Marci Stitzlein says:

I have thyroid issues as well and was recently diagnosed with gluten intolerance too. For about 6 months I was having severe swelling in the right side of my neck and throat, headaches, and ringing in my ears. After several doctors no one could figure out why. It dawned on me that I had started the Synthroid about the same time as when the symptoms started. On my own, I stopped the Synthroid and amazingly all the symptoms I had been having went away. My endocrinologist said she had never seen anyone with that kind of adverse reaction to the drug.

I don’t know if it was due to gluten or something else in the Synthroid but I definitely had a severe reaction to it. I now take Tirosint and I’m doing great. :-)

January 4, 2013 at 8:19 pm
(17) Rhonda says:

I was prescribed Sythroid and had a reaction that got worse with each increase. Sore muscles achy joints. At 75 mg I called my Dr and told her that was the only change I had made and needed to see about an alternative. We changed to Armour and my symptoms immediately subsided. She said it was not the first time she had seen a reaction to the fillers. Havent researched what filler it was yet.

April 23, 2013 at 11:11 am
(18) Cindy says:

I started going gluten free in 10/2012 b/c I had tendonitis in my knee & the Meloxicam the ortho dr rx’d wasn’t working. Amazingly my knee pain went away w/in a few days of cutting out gluten. I also felt better than I had in years. In 11/2012 I went to an ENT who rx’d Armour thyroid medicine b/c I have multinodular goiter. I felt awful. Just like I did when I was eating gluten. I felt like I had arthritis all over my body. So, I stopped taking it (which I didn’t need to anyways since my thyroid panel is always normal). I talked to the ENT about it & it was like I was making it up. They’d never heard of such a thing. Then the other day I picked up a medication in the pharmacy & it said “gluten free” which made me wonder. If at some point I have to take a thyroid medicine, I’ll make sure it’s gluten free.

January 22, 2014 at 1:02 pm
(19) Dallasite says:

There are no ingredients in Synthroid that contain gluten, however, it does contain lactose which may cause GI disturbances for people who are lactose intolerant. Please do not confuse generic thyroid medication with branded Synthroid as they are not the same.

February 8, 2014 at 2:53 pm
(20) Jeri says:

I am allergic to milk, corn, wheat, soy and yeast. All of my scripts have corn starch and lactose or milk protein, Synthroid, Diltiazem ER and Advair Discus and even acetomenaphen. What am I to do? My upper respiratory allergies are worse since starting Diltiazem. Now I am using proair occasionally because of this and soon will have to use my updraft. So my meds that are supposed to make me well are making me sick. Medical advisors say its just a little and laugh at me reading and frustration.

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