Ozempic and Mounjaro warning update: fresh label changes, contraception advice, and what today’s safety alerts mean for weight loss

New safety updates issued in the past 24 hours have tightened guidance for Ozempic (semaglutide) and Mounjaro (tirzepatide), the blockbuster GLP-1–based medicines used for type 2 diabetes and widely adopted for weight loss. Regulators have aligned class-wide warnings about suicidal thoughts or behaviors, and—specific to tirzepatide—introduced new contraception advice for anyone relying on oral birth control during treatment. These moves don’t change how effective the medicines are, but they do sharpen how prescribers and patients should manage risk in real life.

Today’s Ozempic/Mounjaro warning changes at a glance

• Mental health monitoring (class-wide): Labels for GLP-1 and dual GIP/GLP-1 medicines now emphasize vigilance for new or worsening depression, suicidal ideation, or unusual mood changes. Patients and families are urged to seek medical advice promptly if these emerge, and prescribers should assess history of mental-health conditions when starting or escalating doses.

• Contraception (tirzepatide/Mounjaro): Because tirzepatide can reduce the effectiveness of oral contraceptives around dose initiation and each dose increase, patients are advised to switch to a non-oral method or add a barrier method for 4 weeks after starting and for 4 weeks after every escalation. GLP-1–based medicines should not be used during pregnancy, and effective contraception is recommended throughout treatment.

• Who’s affected: People taking Ozempic, Wegovy, Mounjaro and other GLP-1–class medicines for diabetes or obesity, including eligible returning users who may be re-initiating therapy after a break.

Ozempic side effects: what remains most common—and what is rare

Most Ozempic side effects occur in the gastrointestinal tract, especially during the first weeks or when doses increase:

• Common: nausea, vomiting, diarrhea, constipation, abdominal pain, decreased appetite, reflux, and belching. Slower stomach emptying is part of how the drugs work and explains many of these effects.

• Less common but important: gallbladder problems (including gallstones), pancreatitis (severe, persistent abdominal pain that may radiate to the back), kidney function changes (often secondary to dehydration from vomiting/diarrhea), and hypoglycemia if combined with insulin or a sulfonylurea.

• Vision signal (semaglutide): Earlier this year, European safety reviewers concluded that a rare eye condition (NAION, a type of optic nerve damage) is a very rare side effect of semaglutide medicines; anyone with sudden vision loss or a “shadow/curtain” effect should stop the drug and seek urgent care.

Both semaglutide and tirzepatide in the United States carry a boxed warning about thyroid C-cell tumors seen in rodent studies. People with a personal or family history of medullary thyroid carcinoma or MEN2 are advised not to use these medicines.

Mounjaro side effects: where today’s update changes real-world practice

Mounjaro shares many of the gastrointestinal effects listed above, with nausea and diarrhea leading reports. Today’s change adds a practical step for those on oral contraceptives:

• Plan around escalations: Before starting tirzepatide—or before moving up to the next dose—arrange a non-oral contraceptive (e.g., IUD, implant, ring/patch as advised) or add condoms for 4 weeks after each change. This buffer covers the window when absorption of oral pills may be less reliable.

• Preconception planning: People trying to conceive should discuss when to stop tirzepatide (and any GLP-1) well in advance; these drugs are not recommended during pregnancy or breastfeeding.

Counterfeit and compounding cautions

Separate from today’s label actions, authorities have flagged counterfeit and compounded GLP-1 products as ongoing risks. Patients should fill prescriptions through legitimate pharmacies, confirm correct pens and packaging, and avoid products marketed without a prescription or outside regulated supply chains.

What patients should do now

• If you’re on Ozempic, Mounjaro, or similar:

  • Watch for mood changes or suicidal thoughts and contact a clinician promptly if they occur.

  • For tirzepatide users on oral contraception, implement backup or non-oral methods for 4 weeks after starting and after every dose increase.

  • Report severe or persistent GI symptoms, signs of pancreatitis, or vision changes immediately.

  • Stay hydrated, escalate doses gradually, and ask about temporary dose holds if side effects spike.

• If you’re considering GLP-1 therapy for weight loss:

  • Review medical history for thyroid cancer risks, pancreatitis, gallbladder disease, and mental-health conditions.

  • Clarify pregnancy plans and contraception before the first prescription.

  • Set expectations: most side effects are dose-dependent and ease with time; slow titration and diet adjustments (smaller, protein-forward meals; lower fat; limited alcohol) help.

Key takeaways on Ozempic warning and Mounjaro safety

Today’s updates don’t diminish how powerfully these medicines lower A1C and support weight loss, but they do refine the playbook for safe use: keep a close eye on mental health, protect against contraceptive gaps with tirzepatide, avoid use in pregnancy, and escalate doses thoughtfully. With clear counseling and proactive monitoring, most patients can navigate the side-effect curve while retaining the metabolic benefits that made GLP-1 therapies a breakthrough in the first place.