Question to those of you on Euthyrox: Now that I... - Thyroid UK

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Question to those of you on Euthyrox


Now that I'm back on levo (or at least will have to combine levo with NDT/T3 since NDT seems to contain too much T3 and not enough T4 for me), I wonder how the recent reformulation has affected Euthyrox. They replaced sucrose with mannitol, and I know there have been a lot of problems with Teva's levothyroxine which contains mannitol.

I recently contacted the manufacturer, Merck, and was told the new version is not available in all countries yet, but will be as of mid-2021.

Has anyone tried the new version (with mannitol) yet and, if so, how does it work compared to the old version?

If the new Euthyrox turns out to be as problematic as Teva, I'll have to switch to another brand.

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In Germany we have this new Euthyrox with Mannitol and citric acid since October 2019.

I’m using Euthyrox since 2012. I was doing just great until recently when I started taking new Euthyrox with Mannital. First I got severe headache just in the middle of my head. No pain killer helped me and it was really a strange headache which I never had in my life before.

Then I read one person on German health forum said to take half of it to reduce the side effects. I did and from 50 mcg I cut it down to 25mcg, But after 3 weeks and until now severe legs and arms cramps have started. The pain is so sever that I can’t move. I went for a thyroid test which came normal though I minimized my dosage and my house doctor has no answer for that. So, I did some research and got to know one other German person had same issues like I am going through. He switched to another thyroid medication without Mannitol and now feeling better.

What I noticed that when I started taking last Euthyrox medication I immediately developed BP especially I got high diastolic number but after having this new Euthyrox my diastolic BP went down that my nephrologist cut down my BP medication to half dose and now I’m on candesartan 4 mg . But now I’m confused whether to continue or switch to another thyroid medication as this one has made me handicapped due to severe leg and arm pain but it has solved my diastolic BP issue. Nevertheless, it looks like I have to switch to another thyroid medication without mannitol so that I can sleep, sit and walk,

The good thing about Euthyrox is it has no cellulose (wood pulp) binding agent while rest of the thyroid medication do have and I read wood pulp is not for human to digest and it creates long term health issues. This is making me also confused to whether or not switch to another thyroid medication or keep taking new Euthyrox and get use to of sever body aches. 🙈

Hidden in reply to Sandy287

Ok, thanks, that was what I was afraid of, having read about all the problems with Teva which contains mannitol. I will make sure I get a different brand. It`s such a shame since Euthyrox used to be a good brand...:-(

Sandy287 in reply to Hidden

I echo you. And it is really hard decision for me to switch to another brand especially when they have cellulose as a binding agent. I checked L-Thyroxine from beta Pharma German generic thyroid medication has no Mannitol but again it has cellulose.

Hidden in reply to Sandy287

Is this available in Germany:

It's the only other brand of thyroxine available in Belgium and I have heard good things about it.

helvellaAdministrator in reply to Hidden

This document has a lot of the available levothyroxine products in the EU (and some from the UK).

Hidden in reply to helvella

Thanks a lot, Helvella!

I cannot for the life of me understand why manufacturers insist on including cellulose in thyroid meds, since it's known to inhibit absorption of thyroid was when cellulose was increased that Armour started going downhill and many patients who had done great on it for decades had to switch to other brands.

I believe lactose is also problematic in this context (affects thyroid hormone absorption)?

helvellaAdministrator in reply to Hidden

I recently posted this paper which says that lactose, sorbitol and mannitol are ALL incompatible with levothryoxine.

Whilst I can understand historic formulations contains these and other unsatisfactory ingredients, it is truly unacceptable that new formulations, and re-formulations, continue to include them.

I'd like to see Tirosint, Tirosint-Sol properly investigated and assessed - although some love them, others seem to have issues. But at least they avoid all previously known problem exceiptients. :-)

Stability and Compatibility Studies of Levothyroxine Sodium in Solid Binary Systems—Instrumental Screening


Ionuț Ledeți 1,†, Mirabela Romanescu 1,†, Denisa Cîrcioban 1,†, Adriana Ledeți 1,*,†, Gabriela Vlase 2,†, Titus Vlase 2,†, Oana Suciu 3,*,†, Marius Murariu 4,*,†, Sorin Olariu 4,†, Petru Matusz 5,†, Valentina Buda 6,† and Doina Piciu 7,8,†

1 Department of Pharmacy I, Faculty of Pharmacy, Victor Babes University of Medicine and Pharmacy, 300011 Timișoara, Romania

2 Research Centre for Thermal Analysis in Environmental Problems, West University of Timișoara, 300115 Timișoara, Romania

3 Department of Medicine XIV, Faculty of Medicine, Victor Babes University of Medicine and Pharmacy, 300011 Timișoara, Romania

4 Department of Medicine X, Faculty of Medicine, Victor Babes University of Medicine and Pharmacy, 300011 Timișoara, Romania

5 Department of Medicine I, Faculty of Medicine, Victor Babes University of Medicine and Pharmacy, 300011 Timișoara, Romania

6 Department of Pharmacy II, Faculty of Pharmacy, Victor Babes University of Medicine and Pharmacy, 300011 Timișoara, Romania

7 Department of Nuclear Medicine, Prof. Dr. Ion Chiricuță Institute of Oncology, 400015 Cluj-Napoca, Romania

8 Department of Oncology, Faculty of Medicine, Iuliu Hațieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania

All authors contributed equally to this work.

Pharmaceutics 2020, 12(1), 58;

Received: 13 November 2019 / Revised: 4 January 2020 / Accepted: 7 January 2020 / Published: 10 January 2020

(This article belongs to the Special Issue Drug Stability and Stabilization Techniques)


The influence of excipients on the stability of sodium levothyroxine pentahydrate (LTSS) under ambient conditions and thermal stress was evaluated. Since LTSS is a synthetic hormone with a narrow therapeutic index, the interactions of LTSS with excipients can lead to a drastic diminution of therapeutic activity. Ten commonly used pharmaceutical excipients with different roles in solid formulations were chosen as components for binary mixtures containing LTSS, namely, starch, anhydrous lactose, D-mannitol, D-sorbitol, gelatin, calcium lactate pentahydrate, magnesium stearate, methyl 2-hydroxyethyl cellulose (Tylose), colloidal SiO2 (Aerosil) and talc. As investigational tools, universal attenuated total reflectance- Fourier transform infrared spectroscopy UATR-FTIR spectroscopy and thermal analysis were chosen and used as follows: UATR-FTIR spectra were drawn up for samples kept under ambient conditions, while thermoanalytical tools (TG/DTG/HF data) were chosen to evaluate the inducing of interactions during thermal stress. The corroboration of instrumental results led to the conclusion that LTSS is incompatible with lactose, mannitol and sorbitol, and these excipients should not be considered in the development of new generic solid formulations. View Full-Text

Keywords: levothyroxine sodium; excipient; preformulation study; instrumental analysis

Full paper freely accessible at:

Sandy287 in reply to helvella

Many thanks for the info. I checked but it seems this brand is not available in Germany. I have to check other thyroid medicine avialble in Germany and without Mannitol and cellulose.

Sandy287 in reply to helvella

Thank a lot Helvetia! I’m checking the list, hopefully I get one in Germany which has no Mannitol and cellulose.

helvellaAdministrator in reply to Sandy287

I was very happy on L-Thyroxin Henning - but it does have a cellulose ingredient:

Corn starch, pre-gelatinized starch (corn), microcrystalline cellulose, sodium carbonate, sodium thiosulfate (Ph. Eur.), Highly disperse silicon dioxide, hydrogenated castor oil.

(Google translate so do double-check accuracy.)

You can enjoy checking the others listed here:


Sandy287 in reply to helvella

Thanks again. I have to do research on that before switching to another medication and your given list seems promising.

Hidden in reply to helvella

Thanks again! I guess the cellulose content also plays a role...after all, Armour contained some cellulose before the 2009 reformulation, but patients loved it. Then, after more cellulose was added, patients started complaining of a return of hypo symptoms. It seems the same thing happened to Naturethroid (according to STTM).

helvellaAdministrator in reply to Hidden

Who knows?

After all, most of us have no idea about the differences between the various celluloses that might be used.

For example:

Microcrystalline cellulose

Carboxymethyl cellulose

Hydroxypropyl cellulose

Methyl cellulose

powdered cellulose

Many vegetable origin substances intrinsically contain cellulose.

Or, by "E" number:

E460 Cellulose

E461 Methyl cellulose

E462 Ethyl cellulose

E463 Hydroxypropyl cellulose

E464 Hydroxypropyl methyl cellulose

E465 Ethyl methyl cellulose

E466 Carboxy methyl cellulose

E468 Crosslinked sodium carboxy methyl cellulose

E469 Enzymatically hydrolysed carboxy methyl cellulose

Quite possibly one form is an issue, another isn't, or at least is much less an issue. And even within some of these, there will be many variations - such as chain length, fineness of grind, etc.


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