Zepbound went from 112 adverse event reports in 2023 to 31,938 in just 2.5 months of 2025. Mounjaro doubled. But pharma executives are NOT selling. The answer is counterintuitive — and important.
Choose your depth. The data doesn't change — just the explanation.
More adverse events = more prescriptions. These aren't danger signals — they're market signals. Insiders know the difference. But regulators treating raw counts as danger indicators are missing the story.
FDA FAERS API data. Tirzepatide (Zepbound/Mounjaro) growing 219%. Semaglutide (Ozempic) doubling. Adalimumab (Humira) declining as biosimilars take market share.
Form 4 SEC EDGAR filings. More adverse events = FEWER insider filings (r = -0.11). Insiders interpret rising reports as market growth, not liability.
Annualized from 2025 Q1-Q2 data. The GLP-1 class now dominates the FDA adverse event database.
When prescriptions grow faster than adverse events, the per-patient rate is actually declining. This is the regulatory trap: raw counts look alarming; rates tell the real story.
Index: 2022 = 100 for both series. Source: CMS Part D utilization data + FDA FAERS. Note: When prescriptions grow faster than adverse events, the per-patient rate is actually declining.
Full picture across the major drugs in the dataset. Note the inverse: drugs growing in prescriptions grow in adverse events. Drugs losing market share (Humira) decline in both.
| Drug | Company | 2023 Q1 | 2024 Q1 | 2025 Q2 | Growth | Insider Trend |
|---|---|---|---|---|---|---|
| Tirzepatide (Mounjaro/Zepbound) | Eli Lilly (LLY) | 4,886 | 6,989 | 15,596 | ↑ 219% | ↓ -53% selling |
| ↳ Zepbound top adverse events: incorrect dose (32%), nausea (13%), injection site pain (12%). The dominant signal is dosing confusion — not pharmacological danger. | ||||||
| Semaglutide (Ozempic/Wegovy) | Novo Nordisk (NVO) | 3,399 | 5,353 | 3,774 | ↑ 11% (Q2 dip) | ↑ 31→0 (peak then pause) |
| Adalimumab (Humira) | AbbVie (ABBV) | 17,925 | 8,531 | 6,749 | ↓ -62% (biosimilars) | Stable Q1-heavy pattern |
Adverse event raw counts are a misleading signal without per-prescription normalization. Tirzepatide's 15,596 reports in Q2 2025 look alarming — but they reflect explosive adoption by millions of patients, not emerging danger. A drug prescribed to 10 million people will generate more reports than one prescribed to 100,000 even if it's perfectly safe. The FDA knows this. Not all journalists do.
Eli Lilly insiders went from 53 Form 4 filings (Q1 2023) to 25 (Q4 2024) — a 53% reduction in insider activity during the period of maximum adverse event growth. This is the opposite of what you'd expect if executives thought bad news was coming. Adverse events scaling with prescriptions = the business is working. Not selling = they're holding their best cards.
Headlines about "soaring adverse events" for GLP-1 drugs are not necessarily alarm signals. More prescriptions = more reports. Always ask: per how many prescriptions?
Insider selling patterns around adverse event spikes are a real signal — but the current data shows insiders are NOT treating adverse events as sell triggers for GLP-1s. They're holding.
Raw adverse event counts without per-prescription normalization mislead policy. The FDA needs CMS Part D utilization data to contextualize FAERS numbers.
Humira's declining adverse events aren't a safety improvement — it's patients switching to biosimilars. The drug isn't safer. It's losing market share. Context matters.