Ozempic to Mounjaro Conversion Chart (Safe, Evidence-Based Guide)

What This Chart Is—and Isn’t

There’s no official 1:1 “equivalent dose” between semaglutide (Ozempic) and tirzepatide (Mounjaro). Professional guidance prioritizes individualized titration rather than milligram-for-milligram swaps, as laid out in the ADA’s 2025 Standards of Care chapter on Pharmacologic Approaches to Glycemic Treatment (diabetesjournals.org). Institutional aids such as the BILH GLP-1RA Conversion Guide present approximate starting points and explicitly state that charts do not replace clinical judgment. Use our chart to frame a plan with your prescriber, not to self-adjust doses.

How the Medicines and Dosing Differ

Active agents and class. Ozempic contains semaglutide, a GLP-1 receptor agonist. Mounjaro contains tirzepatide, a dual GIP/GLP-1 receptor agonist. That extra GIP activity changes both tolerability profiles and how people respond, which is why there is no mg-to-mg equivalence between the two drugs.

Labeled titrations. Per the Ozempic prescribing information, treatment begins at 0.25 mg once weekly for 4 weeks (a tolerance-building step), then increases to 0.5 mg, with further increases to 1 mg and 2 mg as needed after at least 4 weeks on each level (FDA label). The Mounjaro prescribing information starts at 2.5 mg once weekly for 4 weeks, then 5 mg, with 2.5-mg step-ups (7.5 → 10 → 12.5 → 15 mg) based on response and tolerability (FDA label).

Devices and practicalities. Ozempic pens dial to the labeled weekly doses (0.25/0.5/1/2 mg), while Mounjaro pens are single-strength, prefilled for each step (2.5–15 mg). In practice, clinicians choose the next labeled starting dose that matches prior tolerance and goals rather than attempting a mathematical conversion, which helps keep patients safe during transitions.

When to Start the New Medication After Your Last Dose

General rule. Because both medicines are once-weekly, most switches are timed to your next scheduled weekly dose to avoid overlap. Use the product labels’ missed-dose windows as safety guardrails while you coordinate with your prescriber: the Ozempic prescribing information allows a missed dose to be taken within 5 days, whereas the Mounjaro prescribing information allows within 4 days (96 hours). These windows help you avoid “double dosing” and minimize GI side effects as you change therapies.

Ozempic → Mounjaro (typical timing)
• If your last Ozempic shot was ≤5 days ago, start Mounjaro on your regular weekly day and do not repeat Ozempic.
• If it’s been >5 days, wait for your usual weekly day and begin Mounjaro then. This keeps the schedule clean and reduces stacking risk.

Mounjaro → Ozempic (typical timing)
• If your last Mounjaro shot was ≤4 days ago, switch to Ozempic on your usual weekly day without a catch-up Mounjaro dose.
• If it’s >4 days, skip the missed Mounjaro and start Ozempic on your regular day. Always confirm the plan with your prescriber based on symptoms and glucose trends.

Starting Doses When Switching From Ozempic to Mounjaro

Principle. Treat the change as a new start on tirzepatide rather than a milligram-for-milligram swap. The Mounjaro prescribing information instructs clinicians to begin at 2.5 mg once weekly for 4 weeks, then increase to 5 mg, with additional 2.5-mg step-ups (7.5 → 10 → 12.5 → 15 mg) as needed and tolerated. The ADA Standards of Care (2025) emphasize individualized titration based on response and side-effect profile, which is why most switches follow the labeled on-ramp rather than an “equivalent” dose mapping.

If you were on 0.25–0.5 mg Ozempic. Start Mounjaro 2.5 mg weekly for 4 weeks, then 5 mg. Reassess at week 8; if more effect is needed and tolerability is good, plan further step-ups after spending ≥4 weeks at each level.

If you were on 1 mg Ozempic. Many patients still start at 2.5 mg to minimize GI effects when moving from GLP-1 to dual GIP/GLP-1. In carefully selected, well-tolerant patients, some clinicians may consider starting at 5 mg with close follow-up, but the labeled 2.5-mg on-ramp remains the safest default.

If you were on 2 mg Ozempic. Options include (a) the conservative 2.5 mg → 5 mg path or (b) start at 5 mg if prior GLP-1 tolerance was excellent and the clinician prefers not to “de-titrate.” In either case, escalate by 2.5-mg increments no faster than every 4 weeks, pausing or stepping back if nausea, vomiting, or dehydration appear.

Monitoring. Track A1C (or CGM/SMBG trends) and GI tolerability through weeks 4–8. Hold titration during significant side effects, resume after stabilization, and confirm the plan with your prescriber for safety.

Starting Doses When Switching From Mounjaro to Ozempic

Principle. Treat the switch as a new start on semaglutide rather than an “equivalent milligram” exchange. The Ozempic prescribing information directs clinicians to start at 0.25 mg once weekly for 4 weeks (tolerance-building), then increase to 0.5 mg, and if needed to 1 mg and 2 mg after at least 4 weeks at each level, using patient response and side-effect history to guide the ramp.

If you were on 2.5–5 mg Mounjaro. Begin Ozempic 0.25 mg weekly for 4 weeks, then 0.5 mg. Reassess at week 8; if control is inadequate and tolerability is good, consider 1 mg after another ≥4 weeks. This conservative on-ramp helps minimize nausea and dehydration.

If you were on 7.5–10 mg Mounjaro. Default to 0.25 mg → 0.5 mg, then 1 mg as indicated. In select, well-tolerant patients under close supervision, some clinicians may begin at 0.5 mg, but the labeled on-ramp is the safest default for most people.

If you were on 12.5–15 mg Mounjaro. Even after high-dose tirzepatide, avoid mg-to-mg mapping. Start 0.25 mg, progress to 0.5 mg, then 1–2 mg based on glycemic data and side effects.

Monitoring and transition tips. Track A1C and daily CGM/SMBG trends; pause or step back a dose for significant GI symptoms, then resume after stabilization. The ADA Standards of Care (2025) emphasize individualized titration and shared decision-making over fixed conversion tables, which applies directly to this switch.

Titration, Monitoring, and What to Track

Titration rhythm. After a switch, increase no faster than every 4 weeks, and only if current goals aren’t met and side effects are acceptable. The ADA’s 2025 guidance on pharmacologic approaches to glycemic treatment emphasizes patient-specific titration, pausing or stepping down during significant nausea, vomiting, or dehydration, then re-advancing once symptoms settle and glucose trends are stable.

What to track. Check A1C about every 3 months during active titration; follow CGM/SMBG for fasting and post-meal trends; log weight weekly; and watch blood pressure if you use antihypertensives. Document GI effects, abdominal pain, and signs of pancreatitis or gallbladder disease, and assess hypoglycemia risk if insulin or a sulfonylurea is on board. Shared decision-making with your prescriber should guide each adjustment, ensuring safety and sustained benefit.

Safety First: Contraindications, Cautions, Interactions

Who should not use these drugs. Both products carry a boxed warning for medullary thyroid carcinoma (MTC) and are contraindicated with MEN2 or a personal/family history of MTC; they also carry warnings about acute pancreatitis and should be stopped if pancreatitis is suspected. Additional cautions include gallbladder disease, acute kidney injury secondary to severe GI losses, and diabetic retinopathy progression with rapid A1C improvement; risk of hypoglycemia rises if combined with insulin or a sulfonylurea, so doses of those agents may need review.

Special interaction note (tirzepatide). During Mounjaro dose escalation, delayed gastric emptying can reduce absorption of oral contraceptives; labels advise using non-oral or backup contraception for 4 weeks after initiation and after each dose increase. Discuss pregnancy plans, breastfeeding, and comorbidities with your prescriber before switching therapies to ensure safety.

Disclaimer

Disclaimer: This website connects patients with licensed healthcare providers who can evaluate medical conditions and prescribe medications when appropriate. Some medications available through this service may be compounded drugs, which are customized formulations prepared by a pharmacy. The FDA does not conduct premarket review for compounded drugs to evaluate their safety, effectiveness, or quality. (See here: https://www.fda.gov/consumers/consumer-updates/it-really-fda-approved). Individual results may vary, and these medications should only be used under the guidance of a qualified healthcare professional. The information in this article is for educational purposes only and should not be considered medical advice. Always consult your healthcare provider before starting any new treatment.