What dosage did you take and what supplier did you use?
100 mcg. The first bottle was Thyrocuts 2, and when that was discontinued, I tried the "New! Improved!" version T2 Xtreme, which also included 100 mcg of 3-3 diiodothyronine, but which didn't work any differently. They were from San Corporation (
www.sann.net), but they don't seem to offer any T2 products anymore. Amazon has a different T2 product listed, but it's unavailable. T2 was a fad for weightloss and bodybuilding at one time, so there were several products available. A quick check didn't find any now.
For me, a small drop of tincture of iodine was just as effective, so I assumed that my thyroid gland was converting enough of it directly to T2 to be equivalent to 100 mcg. I can't remember testing for the absolute minimum of T2 that worked for me, but I assume that I tried half the amount and found that was not enough.
180 capsules lasts a very long time at one per 21 days, so at one point I noticed that the T2 wasn't working. When I checked the bottle, it was I think 2 years past the expiry date, so I guess it had weakened over time. I think two of the aged capsules did the trick, for the next few required doses, and that was the end of that bottle. Since I couldn't buy more, I switched to iodine, which worked just as well for me.
T2 (or iodine) certainly kept me from much worse symptoms for quite a few years. I'm grateful that T2 was available at that time, and that iodine worked just as well, when the San product was discontinued.
In case it's of interest: when I first experimented with T2, the first capsule game me remission, but the symptoms started coming back over the next few days, despite taking one or more doses each day, until I was back to feeling my regular baseline symptoms. When I quick taking the daily T2, my symptoms worsened significantly, then gradually reduces at about the same rate as the improvement had tapered off. I think this was my thyroid gland reducing its production of T2 in response to the supplement, and then gradually taking up the load again when I stopped the supplement. 21 days after that, the symptoms abruptly increased again, and one dose of T2 'reset something' for another 21 days. Since my body was being quite clear about its demand for one dose every 21 days, I was happy to comply.
Oh, the first time I noticed an effect from iodine or any other thyroid-related supplement, it was 150 mcg of potassium iodide in a multivitamin/mineral tablet. Thus it didn't need to be tincture of iodine. The iodine atoms in T4 or T3 didn't work, although I think I never took 100 mcg worth. 50 mcg of T4 made my heart feel a bit odd (faster rate?), so I didn't experiment further that way.