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Thyroid UK
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Favorite T4 Brand?

What brands do people prefer for T4? I have tried lots of different brands over the years and in my experience they all have different effects, is very annoying as they are meant to all work the same! The fillers are different in the various brands but sometimes it seems like something else is going on.

Here are some I have tried:

Mercury Pharma: normal dose seems to make me hyper, also causes water retention (could be from Acacia filler)

Sanofi-Aventis: seems to be very weak, either that or the dose isn't consistent between tablets. I gained weight and had hypo symptoms on normal dose

Aliud: felt horrible on this, made me very hyper so quickly stopped

Zentiva: completely ineffective, very bad hypo symptoms after a few days

Thyronorm, Abbot: extreme muscle loss and low libido and anxiety - this was the worst of them all

GSK Eltroxin: edema, dry hair/skin from first dose - didn't continue

Berlin Chemie: Best I have used and currently use it. No side effects that I can tell and is potent/absorbs well

I'm sure there is more but that is all I can think of now!

Can anyone else share their 'T4 reviews'? :)

7 Replies

You need to stick with a brand that you are happy with as you say different fillers can have a different effect or be an allergy but the amount in the Levo can change to as the manufacturers work to be within a set range so if you change from one that is at the top of the high end to one down at the bottom

It can make a real difference to how you are feeling. So stick with one the fillers are right for you. Get it bamed on your prescription so the pharmacy bad to supply that one and then get you blood checked after 6 weeks it you feel different to make sure you are on the right dose for you on that brand.

1 like

I liked both Aliud (you have also mentioned but did not like) and Henning L-Thyroxin.

Both seemed slightly more potent than Mercury Pharma and Actavis - but I suspect that it is that Mercury Pharma and Actavis do not deliver as effectively for some reason.

We never find out what impurities are present in the tablets. I suspect that low levels of various impurities and/or breakdown products of the levothyroxine, including substances formed by reactions between levothyroxine and the other ingredients, might be having an effect. Maybe the source of the levothyroxine ingredient itself is significant?

For example (and I do not think this is the issue - just I know the figures) both UK and USA standards appears to allow up to one percent of dosage in levothyroxine to be liothyronine/T3. That is, a 100 microgram tablet could actually have one microgram of T3. Other standards apply to other know impurities.

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I recently switched from Mercury to Henning L-Thyroxin because I get my T3 from Henning Thybon and I thought it would be better to have T4 and T3 from the same company. Bought it in Germany, though, with help of cousin's husband who is a GP. I think it is more potent as my FT4 has gone up in blood tests . I am happy with the make, not so happy with the dose of T3 (due to endo not wanting to increase it).

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I can only take Tirosint. I'm in the USA.


Teva. I found this ok.


I liked Eltroxin but can no longer get this; I like Mercury Pharma but have been put on Actavis which I didn't like. The new formulation was terrible and made me sweat.



I tried Henning which didnt agree with me at all, Mercury Pharma was the devils spawn have never felt so ill on it, am now on Wockhardt and touch wood! am doing okay on it at the moment



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