Thyroid function monitoring on GLP-1 — anyone have experience?

that TPO antibody reduction is really interesting. There's actually a 2024 study in *Thyroid* journal (doi: 10.1089/thy.2023.0412) showing GLP-1 RAs reduced TPO antibodies by a mean of 31% in Hashimoto's patients over 12 months. The proposed mechanism is reduction in visceral adipose tissue, which is a major source of inflammatory cytokines that drive thyroid autoimmunity. Your 43% reduction in 9 months exceeds their average, probably because you're also getting the anti-inflammatory benefits of significant weight loss.

I have a family history of thyroid cancer (my aunt had papillary thyroid cancer). My PCP won't prescribe GLP-1 because of the black box warning. Is this warranted or should I get a second opinion?

— papillary thyroid cancer is NOT medullary thyroid cancer. They are completely different cell types. The black box warning specifically relates to C-cell tumors (medullary thyroid carcinoma / MTC), which arise from calcitonin-producing cells. Papillary thyroid cancer arises from follicular cells and has zero relationship to GLP-1 receptor activation. The contraindication is for: personal or family history of MTC or Multiple Endocrine Neoplasia syndrome type 2 (MEN2). Family history of papillary thyroid cancer is NOT a contraindication. I would respectfully suggest getting a second opinion from an endocrinologist who can clarify this distinction. Your PCP may be erring on the side of caution, which is understandable, but in this case the caution is based on a misunderstanding.

Update: Increased my calories to ~1500/day with focus on protein (hitting about 95-100g). Also started selenium 200mcg. Only been a week but I already feel less cold and have slightly more energy. Getting labs rechecked in 6 weeks. Thanks for the reality check everyone — this thread genuinely reduced my anxiety. 🙏

Glad to hear it! And also, definitely get that second opinion. The distinction between papillary and medullary thyroid cancer is a really important one that not all PCPs are clear on. An endocrinologist will be able to properly risk-stratify you. Don't let a misunderstanding keep you from a medication that could genuinely help your health.