The bit that stood out to me is the 4 weeks off. You did the one thing most people never do, you pulled the variable out, and the pain didn’t budge. That’s not a dead end, that’s data. It points away from the drug doing it directly and toward something that doesn’t reverse in a month. Two explanations worth keeping separate, because they ask for different fixes: One, the compound itself. If tirz or sema were driving it through some direct mechanism, four weeks off should have at least dented it. It didn’t. So I’d put that one lower on the list, not off it, just lower. Two, the mechanical side. You’ve been losing weight since June 2024. The fat pad that sits over your coccyx thins out the same as everywhere else, and now you’re parked on bone you used to have cushioning over. That doesn’t come back when you stop the drug, which is exactly what you’re describing. Add in that a lot of us sit more when we’re knackered, and GLP-1 fatigue is real, so the hours on your tailbone may have crept up without you clocking it. The question I’d ask before blaming either: did your coccyx ever give you trouble before 2024? Old damage isn’t the same starting line as a clean joint. If there was a fall or a rough pregnancy back there, the weight loss might just be unmasking something that was always borderline. Practical bit, fwiw: a coccyx cushion, the ones with the cutout at the back, is a near-free test. If sitting on bone is the driver, that should move the needle in a week or two. If it does nothing, you’ve ruled the mechanical side out cheaply. I’d also log it by date and where it’s worst, sitting vs standing vs first thing in the morning. I keep that sort of thing on a tracker with a watch complication so I actually log it in the moment instead of guessing later, and the sitting-vs-standing split is what tells you mechanical from systemic. Worth raising with your GP too, a quick coccyx xray rules out the boring stuff. Hope the cushion helps, that pain is miserable to live with.