Use by date on Liothyronine: Is liothyronine... - Thyroid UK

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Use by date on Liothyronine

Harebell profile image

Is liothyronine still effective after its use by date? How quickly would it lose its effectiveness, if at all? Thank you.

27 Replies

Manufacturers are conservative on their use by dates. If the drug has been stored correctly you would have quite a long time before the drug starts to degrade. Drugs don't suddenly become ineffective but the amount of active drug might start to be less than stated, so you might note a lessening of the clinical effect. Good luck

I agree with both, I asked mercury pharma, they were a bit well youshould follow the guidelines as it could be less active .

IMO if you keep it in the freezer, that will prolong shelf-life quite a bit.

helvella profile image
helvellaAdministrator in reply to Amazon07

It is vital that it is packed in a sealed container which will prevent any condensation when it is taken out.

I HAVE ACOUPLE of pots that are still sealed that the chemist made a mistake in giving me two instead of one but couldn't take them back a si had gone home but they are still sealed but passed sell by date woul dthey be ok rod?

Personally I wouldn't even contemplate using a drug past its sell by date. I would be too worried about it x

I queried this myself some months ago as my then current prescription of Liothyronine was close to it's expiry date.I asked my Pharmacist about it who assured me that it would be OK.However,I think this is a question that will crop up more frequently If there are fewer people being prescribed it.( my pharmacist only had a few people taking it) Their stock is going to stay on their shelves for longer,unless they order small amounts more often and I can't see them doing that.

My Armour Thyroid which I am now buying,arrives from USA with well over 1year 's shelf life,as it is their policy to always send your order with the longest expiry date on it that they can provide.

The synthetic thyroid hormones are all sensitive to heat and probably will be fine IF they have been stored correctly but if they have had a period above 25 degrees then they are likely to be ineffective (this applies to tablets within their use by date too). The general advice is not to keep them any where you would not keep chocolate as it melts. It is hard to be sure when getting them in the post or if they are being moved around to pharmacies in a non refrigerated van or if the pharmacy does not have air conditioning.


I didn't have any adverse effects when I used some T3 with Sept 15 expiry for a week during March 16.

Have a look at this link

i think it can be used, if you store them correctly shuld be fine. I used 3 years expired levothyroxine, my test results came back as expected, no sides effect whatsoever.

Hi Harebell, Liothyronine has supposedly a 12 months shelf life but in reality I think it is more like 10/11 months. I have noticed a clear difference because when I used a jar slightly out of date (in the bottom of my subscription bag): my temperature dropped to below 35C and I got acutely tired spells. My med. had been stored in a dark and cool place.

The chemist had three jars in stock on the shelf but had to order the rest and used up the new jars first because labels had been stuck over the exp. date.

Hmm Harebell, this is strange because Cynomel [good old Mexican stuff!] used to have 2+ years ahead use by date - I've still got some and I'm spreading it out with another brand. Why would something synthetic have such a short shelf life when even Armour lasts for a long while? Yes of course too high temps affect [as I imagine too low could, not fridge but freezer?]. Much depends on the structure of bonds? I don't know about this at all but just wouldn't chance it - stuff is so precious! Would love someone who does know to advise because this is pretty critical. Maybe my 'on the cusp' Cynomel is not working for me? My goodness, we should all be great at puzzles - working out our own health is the biggest one ever ;-) Take care and be well xx

My old chemist (I've changed because of this) worked out that by the date of the prescription I would just have time to use the short dated T3 they gave me but didn't warn me they were close to the use by date. If they had I would have refused them as I have to halve the tablets so a pot lasts 2 months I usually order things before I run out and they went out of date before I could use them. I did use some out of date and am still here, although at the moment after the 'expert' reduced my dosage of both T3 and T4 and won't prescribe NDT I feel as though I'm not taking anything with all my symptoms coming back.

Also a pot received end of May expires August!

LindaC profile image
LindaC in reply to 1239

Sorry folks, but it seems difficult to accept that these could deteriorate in that timescale!? Surely there is someone on here who has some clue?

I have T3 in the cupboard dated for 2018... something just not right here.

Clutter profile image
Clutter in reply to LindaC


Unless Liothyronine potency has been tested post expiry or someone has taken it post expiry no one will have a clue. I've said above that I had no ill effects taking Tiromel 6 months post-expiry.

The expiry date guarantees potency up until that date. It doesn't mean potency suddenly falls off post expiry. It's not a shelf life thing. See the link in my post above.

LindaC profile image
LindaC in reply to Clutter

Thank you Clutter, yes I did read above. I think my major point is, how come a synthetic has such a short life? I've wished in the past that I could take 'in date' pills to have their potency tested... tried, no one seems to do this. I find it accept to accept that 10 -12 months is the time to use T3 within... if that is the case, much of what I have and used in the past will have been no good!? This doesn't seem to make sense, especially when labelled two+ years ahead... how come?

It is just when some of us have such variable signs/symptoms, we often have no clue as to what is having x or y affect. I wouldn't expect any ill effects, only that dud pills would make us feel worse. :-) x

Clutter profile image
Clutter in reply to LindaC


Tablets are guaranteed to retain their potency until their expiry date if they are stored correctly in cool, dry and dark conditions. That doesn't mean the potency decreases when the expiry date has passed. It just means that if expiry date is 2 or 3 years after manufacture that is the period guaranteed.

LindaC profile image
LindaC in reply to Clutter

Thanks again Clutter, that's what I do and that's what I thought... just couldn't understand why some have such a short date? :-) Yup, I'm taking some on the cusp now.

Think Bettan above - where I too have even lower temps - is the post that had me think more about it, especially with the 10/11 months timescale.

I just treat T3, kept and stored correctly, as fine... have a good weekend and apols for any confusion. xx

Clutter profile image
Clutter in reply to LindaC


Dunno why 2 or 3 years is determined ok. Probably made up on the hoof like 5-a-day and safe-drinking-units and doesn't have any scientific basis.

LindaC profile image
LindaC in reply to Clutter

Right Clutter, so a date of 2017 and 2018 isn't good? OK, back to my previous Q's - how come a synthetic product isn't OK for that length of time? Armour, which is surely more 'delicate' isn't that short in life. Hmmm.

Clutter profile image
Clutter in reply to LindaC


Have I missed something? Why isn't 2017 and 2018 expiry good and why should synthetic T3 need longer expiry than Armour?

LindaC profile image
LindaC in reply to Clutter

Clutter, if you read back... I don't think there are any issues with those dates or ones even on the cusp of the use by or whichever expiry date is given. I was questioning WHY people seem to think there is a problem; IF indeed there is a problem and HOW in fact could there by a problem when they're synthetic [when something more delicate like Armour doesn't even have the 10/11 months as stated above]. There is clearly confusion here... I don't think there is a problem at all, just querying other comments above on this. Thank you in any event; maybe we just leave it here. Take care, be well and have a good weekend. :-)

Amazon07 profile image
Amazon07 in reply to Clutter

Completely agree! I don't see it loosing effectiveness and I wouldn't have (and never had) an issue taking medications past their expiry date (up to a year after expiry). That's just me :-)

Thank you very much for your helpful comments everyone. The expired drug article is very interesting, thank you Clutter.

It's NHS prescribed liothyronine and I just noticed that the bottles obtained from prescriptions on different dates all had the same Use By date. As said above, the chemist must just have one lot of (old) stock that they're using up on me! I was trying to build up a stock, I admit, because my GP had been questioning my use of it a couple of times recently.

"Why are you taking both liothyronine and levothyroxine? You don't take both together".

"Why are you needing to take liothyronine? Your test results are fine". (Doh, maybe my test results are fine BECAUSE I'm taking liothyronine).

This is the same GP who says there's no such thing as a separate test for T3 and the the TSH test tests for T3.

Anyone have experience storing Liothyronine, both tablets & compounded in the deep-freeze??? TIA!

helvella profile image
helvellaAdministrator in reply to unblocktheplane

Although we have seen quite a few posts about freezing medicines, and some seem fine, it is difficult to be certain what will happen.

Things like the hydration of the thyroid hormone can change. Most of us are aware that inside the sealed packaging of some frozen foods, you can get a layer of ice crystals. The water that forms those crystals has come out of the food leaving the food slightly desiccated. A similar process can occur with tablets.

This might, or might not, be important.

I doubt there has been any serious research.

I think I would prefer to store in an ordinary refrigerator rather than a freezer. Though even that must be in air-tight packaging.

Thanks, Helvella. I just got a message from the manufacturers of Cynomel telling me they were fine in the fridge but not the freezer. Hope I haven't damaged them too badly!

Freezer burn. Happens to our salmon but still quite edible!

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