High Free T4 after significant weight loss with GLP1
tldr: Free T4 and TSH all crazy after big weight loss. Anyone else?
Hi, I tried searching for info but couldn't find it, so sorry if this gets asked a lot. I (59f) was diagnosed with hypothyroidism about 20 years ago at 39, been on levothyroxine ever since. And I gained 3-4 pounds per year, most years, for 20 year. You know how it is: ate right, exercised, blah blah. Was a buys single mom, never really dieted, just tried to stay active.
Started Zepbound in Sept 2024 and by June 2025 I had lost 70 pounds. Since June 2025 to May 2026 I have lost another 10 pounds as I figured out maintenance dosing. Current BMI is 22, and in general I feel amazing and strong!
During that time work switched insurance at away from Kaiser to Blue Shield. New doc diagnosed me with Hashimoto's, old doc had just assumed that I had it. Old doc lowered my Levo dose right before the insurance switch due to early weight loss. My TSH went up so the new doc raised my levo dose in mid 2025, even though my free t4 was high.
In Jan my work insurance went back to Kaiser and I returned to my old doc, who I like. TSH was 1.6, Free T4 was 2.0. Since my free T4 was high she explained that I needed to drop my Levo dose again, that dosing is in part based on weight, and that it takes awhile for my pituitary to "see" my new weight and stop demanding so much hormone from my thyroid. So we dropped dose from 112 to 100 and retested in March. She said that my TSH would go up, but that it was basically "fake news" while the pituitary adjusted to my new size. In March, TSH was 3.9 and Free T4 1.9. She dropped dosage again to 75 and after 2 months at this dose I just retested on Friday.
TSH is way up to 6.6, I am still waiting on the Free T4 results. Kaiser usually releases them quick so I'm paranoid that they are being held for her review because they are problematic...
As far as symptoms, in the past week my fatigue has increased, joint pain and sense of inflammation are all up. All very different after a year at this size, a year in which I have become quite the gym rat! Zepbound has been amazing for inflammation, so that worries me. Hopefully I get my free T4 results today and some answers from my doc. Maybe we have found my "floor" and need to go up little bit.
Anyone else have anything similar after a big weight loss?