T3 brand change experiences?


I'm one of those unfortunate people who have been left in the lurch by Grossman Cynomel being currently out of production.

I only need a small dose - three quarters of a 25mcg tablet, (18.75mcg) which I take in five divided doses of 3-4mcg each through the day. My TSH is normally around 1-2 when I get it checked. I've had excellent thyroid health and no complaints on this for around three years, though I do notice I can get a bit sluggish and then get a bit of a temporary hyper feeling when I move from old stuff near its best before to a brand new shipment.

I originally went onto T3 after having a mysterious bad reaction to T4, which seemed to stop working and left me with feelings of being underdosed and overdosed at the same time. I never really settled on T4 and always felt tired, despite ideal TSH. (I'm someone for whom TSH actually is a reasonably accurate indicator. Pushing the dose up just made me hyper.) It's possible the bad reaction I had to T4 was caused by magnesium deficiency, as I was pushing vitamin D quite hard at the time. I don't know. I haven't tried T4 again since as I'm terrified of getting the symptoms back. I was on between 87.5 and 75mcg, which is pretty much exactly the 4x conversion ratio for a dose of 18.75mcg of T3.

Anyway, I'm extremely sensitive to fluctuations in thyroid hormones. I get massive adrenaline overreactions if I take even slightly too much. Even on T4 I had to split it into divided doses through the day or I had panic attacks (something it took me ages to figure out, but did allow me to settle on T4 for a while before getting the bad reaction). I've never met anyone else who had this problem with T4.

So, I've been settled on Cynomel for years and love it, but with Grossman being currently out of production I recently asked for an NHS prescription of MercuryPharma T3, 20mcg, and tried some last week. I had a really, really bad reaction to it: panic attack, palpitations, shaking, etc. This is despite taking less than I would normally for Cynomel - roughly 2.5mcg. I also felt throaty as if I was on dairy (I have an allergy). I'm suspicious of the acacia extract in it, as I've heard it can cross-react with grass pollen allergy, which I have. It probably doesn't help that it was batch 81377, which people seem to have had a bad time on! So, generally an all-round bad experience.

I then tried Tiromel with similar results. I'm tolerating the Tiromel much better than MercuryPharma but still having adrenaline reactions, despite taking doses of only 2.5-3mcg instead of my usual 3-4mcg of Cynomel. I'm struggling to get the doses small enough to not get adrenaline reactions to them. I seem to react to the tiniest amount. Of course it doesn't help that once I get a bit of fear-conditioning about taking something I'm going to get anxious anyway!

The complication is that I've been using up Cynomel that is close to expiry as I've been running out and feeling sluggish for a couple of months, and now my remaining Cynomel has expired. My TSH was tested a couple of weeks ago before I tried to change brands and was 2.75 about an hour after taking my tablet. I would have preferred it to be lower than that at that point, so it's possible my Cynomel has lost some potency.

I wondered if anyone else has had experiences of going hyper when trying to swap to other brands? Cynomel is supposed to be one of the stronger brands on the market so I'm a bit confused by all of this. Maybe I have an issue with the excipients that means either I haven't been absorbing all of my Cynomel dose, or that it's going into my bloodstream much slower than the other brands?

I'm rather worried as it's quite hard to cut the tablets any smaller than I am already. The MercuryPharma stuff is dreadful to cut as it's very crumbly, and though the Tiromel cuts very neatly I seem to be unable to get the dose small enough that I don't react to it.

I've ordered some Triyotex from Mexico, as I hear it's a capsule full of little balls, so I might be able to portion out smaller, more accurate doses than trying to cut up a T3 tablet with a craft knife as I have been doing. Some people say it seems to be slower release (and others say the opposite), and I wonder whether slower release works better for me.

I'm finding all of this very confusing and rather nerve-wracking as I don't know what I'll do if I can't get settled on a new brand. I'm about to start a major home building project and need to be able to do some quite physical carpentry work.

I wondered if anyone else has experienced anything similar or could offer any insight into the contradictory brand strengths some people experience?

Does anyone have any experience with portioning out tiny doses of Triyotex?

Have any of you been through something like this and managed to resolve it or get used to the new brands? Have any of you had to vary your dose downwards on brands other than Cynomel?

Thanks for any info or support!


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  • I'm sorry you are experiencing a disruption in your usual brand of T3. A few of us have found after being on Mercurypharma for a period that they're not so well or develop new symptoms. MP insist it is exactly the same but our bodies don't agree....

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