What the boxed warning says
The boxed warning is narrow and specific. It says semaglutide caused thyroid C-cell tumors in rodents at clinically relevant exposures, but that it is unknown whether Wegovy causes thyroid C-cell tumors, including medullary thyroid carcinoma, in humans.
The warning is real, but it is not the same thing as a proven claim that semaglutide causes cancer broadly in people.
Who should speak with a clinician before or during treatment
The current label says Wegovy is contraindicated for patients with a personal or family history of medullary thyroid carcinoma or with Multiple Endocrine Neoplasia syndrome type 2. MedlinePlus also tells patients to discuss that history and to contact a doctor if they develop a neck lump, hoarseness, trouble swallowing, or shortness of breath.
Those are the main facts to pin down first: thyroid history, family history, MEN 2 history, and whether any neck or swallowing symptoms were documented.
What to document if this warning is part of your timeline
If this warning matters to your situation, keep the product name, when you took it, any personal or family thyroid history, what symptoms showed up, what testing was done, and what clinicians said about the issue.
The useful records are usually office notes, imaging or biopsy records if any exist, medication history, and any charted discussion of thyroid history, MEN 2, or medullary thyroid carcinoma.