The thyroid cancer black box warning on every GLP-1 — why does nobody seem to take it seriously?
So I’ve been researching tirzepatide and semaglutide for a few months now, reading everything I can before potentially starting. One thing that keeps bugging me is the black box warning about thyroid C-cell tumors that’s literally on every single GLP-1 medication. It comes from rodent studies where they got medullary thyroid cancer at pretty high rates.
But then I look at forums, youtube videos, even some doctors on social media, and people seem to just… not really care about it? Like it’s barely mentioned. My own doctor kind of brushed past it when we talked, just said “we don’t do it if you have family history of MTC or MEN2 syndrome” and that was it.
I get that rodent studies don’t always translate to humans, and these meds have been out long enough that we’d probably see signals by now if it was a real risk. But isn’t that kind of cavalier? The warning exists for a reason right?
Is anyone else concerned about this or am I just overthinking it? I tend to be anxious about medication side effects in general so maybe that’s coloring my view here. Would love to hear how others thought through this risk.
I had the same concern when I started on Ozempic last year. My endo actually spent some time explaining that the rodent studies used doses that were way way higher than what humans take, and rats have way more of those specific thyroid cells than we do. There’s been zero cases linked to GLP-1s in humans after millions of prescriptions over like 15+ years if you count the diabetes use. That made me feel better about it. That said, I still mentioned it to my doctor and we agreed I’d get thyroid function checked every 6 months just to be cautious. If you have anxiety about meds (same tbh) maybe ask for periodic monitoring? That way you’re being proactive.
I think Sarah’s point about the monitoring is smart. But honestly I wonder if people don’t take it seriously because we’re all kind of numb to these warnings at this point? Like every medication has a list of terrifying possible side effects that are technically possible but super rare. The obesity itself is a more concrete and immediate health risk for most people than a theoretical cancer risk that hasn’t shown up in human populations. Not saying the warning is meaningless, but I can see why people weigh the known benefits against an unproven risk and decide to move forward. Definitely something to discuss with your doctor though, especially if you have any family history of thyroid stuff.