GLP-1: what to look out for

compounded semaglutide/tirzepatide · counterfeit Ozempic pens

FDA (Jul 2024): dosing errors on compounded injections reached 5–20× the intended dose, with hospitalizations; counterfeit Ozempic was found inside the legitimate US supply chain (Dec 2023, again Apr 2025). With shortages resolved, mass compounding lost its legal basis in 2025, and FDA sent warning letters to 50+ sellers. Poison-center calls: 159 compounded-semaglutide exposures by mid-2024 vs 32 in all of 2023; hospitalization odds for compounded reports ran 2.35× brand products.

every brand: Wegovy, Ozempic, Rybelsus, Zepbound, Mounjaro, Saxenda, Victoza, Trulicity

The strongest warning on every GLP-1 label, from rodent studies (human relevance undetermined). The label rules the drug out for anyone with a personal or family history of medullary thyroid carcinoma or MEN2 — which makes FAMILY HISTORY a formal input the prescriber must screen.

all brands

Label warning on every brand, including postmarketing reports of fatal cases: stop the drug if suspected. Honest counterweight: in the 17,604-person SELECT trial, acute pancreatitis was 0.2% on semaglutide vs 0.3% on placebo — the randomized data shows no excess.

all brands (label update Nov 2024)

Slowed stomach emptying means food can remain despite normal fasting — rare aspiration reports during general anesthesia led FDA to update every GLP-1 label. Practical move: tell every anesthesiologist and surgeon you are on one, well before any procedure.

Ozempic (added Sept 2023), Wegovy, Mounjaro

Added to the Ozempic label after FAERS reports (18 ileus cases at the time, 2 deaths reported; causality not confirmed). Severe, persistent abdominal pain is a call-the-prescriber symptom, not a wait-and-see one.

all brands; rates higher at weight-loss doses

STEP 1: gallbladder-related events 2.6% vs 1.2% placebo; SELECT: 2.8% vs 2.3% over ~3.3 years. Gallbladder-type pain (right upper belly, after meals) is on the symptom watchlist.

semaglutide brands: Ozempic, Wegovy, Rybelsus (EU label, June 2025)

A 2024 Harvard study reported hazard ratios of 4–7×; larger 2025 replications shrank that to ~1.3× and Danish data put absolute risk near 1–2 per 10,000 person-years. EMA ruled it a 'very rare' (≤1 in 10,000) semaglutide side effect and updated EU labels; FDA had made no US label change as of mid-2026. Sudden vision change in one eye = stop-and-call-now.

all brands

Usually secondary: nausea/vomiting/diarrhea → fluid loss → kidney strain. Hydration during dose escalation is the boring intervention that prevents the dramatic one.

all brands (diabetes combinations)

The GLP-1 itself rarely causes lows; the combination does. Anyone on insulin or a sulfonylurea needs the prescriber to plan dose reductions up front.

semaglutide in type-2 diabetes (Ozempic, Rybelsus)

SUSTAIN-6: 3.0% vs 1.8% placebo in diabetic patients — likely tied to how fast blood sugar improves. Distinct from NAION. Diabetics with existing retinopathy need eye monitoring.

named in suits: Ozempic, Mounjaro and others (MDL 3094)

Slowed gastric emptying is the drug's known mechanism; lasting gastroparesis is NOT a US label warning. ~3,900 lawsuits consolidated by Aug 2026 (≈75% gastroparesis claims); no trial verdicts or settlements yet — a federal causation hearing was set for Sept 2026. Courts test claims; they are not evidence by themselves.

all brands (a property of rapid weight loss)

Studies put lean mass at ~25–39% of total weight lost — comparable to other rapid-weight-loss methods, not clearly drug-specific. Resistance training and protein intake are the standing counter-moves worth raising with the prescriber.

OTC products marketed as "nature's Ozempic" (berberine, etc.)

They contain no GLP-1 medicine and don't activate the receptor; FDA warns weight-loss supplements are a known channel for hidden drug ingredients, and 'works like Ozempic' marketing draws enforcement letters. The only oral GLP-1 actually approved is Rybelsus, by prescription.

Saxenda, Wegovy, Zepbound (warning removal requested)

The system worked in reverse here: after 2023 reports, FDA (Jan 2024) and EMA (Apr 2024) reviews found no causal evidence, and FDA's Jan 2026 review of 91 trials (107,910 patients) found no increased risk — FDA asked manufacturers to REMOVE the precautionary warning. Mood changes are still always worth reporting.