Thyroid UK
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Occasionally I see posts which refer to batch numbers of T4 and T3 which may not be as effective as other batch number. Is there a list somewhere with these batch number for T3 on please.

For the past couple of months I have been feeling extremely tired and wondered if my latest batch number fall into this category.

Thanks in advance.


7 Replies

Wendy, There isn't any such list. There can be a potency variation of 90-105% between batches so it is possible to feel undermedicated or overmedicated when you switch batch. What is the batch are currently taking?


Thanks for reply Clutter

I'm taking 2different batches at the moment as I'm on 3x20mcg daily.

My morning and evening dose is batch no 82613 exp 16/6/2016

Lunchtime dose is batch no 82613 exp 16/6/2016. Same as above, I keep these in my lunch box. ( I only use these on week days )

Other batch no is 83200 exp 18/2/2016 I keep these in my handbag for when I'm not at home or have forgotten to a dose at some point. I perk up if I take these !!!

I have been on 82613 for a couple of weeks now and have steadily gone downhill.

Wondering if anyone else has any issues on this batch no?


Wendy, I was on 82613 and am now on 83200. Both were fine for me. I take T3 with T4 so possibly not as sensitive as someone on T3 only.

Why not try 83200 for a few days and see whether it makes any difference. Keep the others as back up.

1 like

Thanks for that clutter. I'm on combo too.

50mcg T4

60mcg T3

I take T4 at bedtime and T3 breakfast lunch and dinner times. Evenly spaced. I'm clutching at straws thinking its a dodgy batch.

I will do as you suggest and take the newest batch throughout the day instead of 2 different batch numbers.

Thanks again x


W3ndy, it may be the potency variance in the batches which is making you feel unwell. If you feel better on 83200 make a yellow card report on 82613. I don't know whether your pharmacy will swop 82613 for 83200 if you explain how you're affected but it's worth asking.


Hi Wendy,

I am currently on batch no 82613 with the same expiration date, also have the same 83200 for next week. I honestly cannot say I've noticed a difference yet in 82613, but I only take 1+1/2 tablets = 30mcg daily. I also take a 25mcg Tiromel at the same time, totally my daily is 55mcg T3. Maybe the duff Merc Pharma cancels out the duff Tiromel, who knows! Hope you sort it out.

Be well



Thanks Liz. C


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