Mounjaro vs Ozempic vs Wegovy

Three brand names, two active ingredients, one general class of medication. They get confused often, sometimes because the names sound similar, sometimes because people see them treated interchangeably in casual conversation. They are not interchangeable, even though the family is the same.

Here is the side by side, then the detail.

The Comparison Table

The Two Active Ingredients

Semaglutide (Ozempic, Wegovy)

Semaglutide acts on the GLP-1 receptor only. It was the first weekly GLP-1 medication to make a major impact on both diabetes care and weight management. Novo Nordisk introduced it for diabetes (Ozempic) in 2017 and then for weight management (Wegovy) in 2021. The two are the same molecule at different dose ranges.

Tirzepatide (Mounjaro)

Tirzepatide acts on both the GLP-1 and GIP receptors. It is the first dual incretin agonist on the market, launched by Eli Lilly in 2022 for diabetes and 2023 for weight management. In head to head and indirect comparison trials, tirzepatide produces larger reductions in both HbA1c and body weight than semaglutide at maximum doses.

The Same Family, Genuinely Different Profiles

All three share the same general mechanism of acting on the GLP-1 receptor. They all reduce appetite, slow gastric emptying, and improve insulin response. They all have similar side effect profiles, dominated by gastrointestinal effects in the early weeks. They all are once weekly injections.

The main differences:

• Tirzepatide adds the GIP pathway. This is the mechanistic difference. The clinical consequence is larger average effects on weight and blood sugar.
• Dose ranges differ. Tirzepatide goes up to 15 mg, semaglutide up to 2.4 mg. The numbers are not directly comparable because the molecules differ in potency.
• SA availability differs. Mounjaro is the only one currently SAHPRA approved for weight management in SA. Ozempic is approved for diabetes only. Wegovy is not yet registered.

South African Availability

This is the practical part. Globally the choice between tirzepatide and semaglutide is a real discussion. In South Africa right now, the choice is narrower because of registration status.

Mounjaro

SAHPRA approved for type 2 diabetes (December 2024) and chronic weight management (October 2025). Distributed by Aspen Pharmacare. Available through SA pharmacies on prescription. Pricing varies by dose. Availability is improving but still patchy at some smaller pharmacies. Confirm with your pharmacy before paying for the consultation.

Ozempic

SAHPRA registered for type 2 diabetes only. Not registered for weight management in South Africa. Pharmacists are not legally permitted to dispense Ozempic for weight loss, and prescriptions for off label weight management use are increasingly being declined. For weight management in SA, Ozempic is not the route.

Wegovy

Not registered with SAHPRA at the time of writing. Novo Nordisk has not announced an SA launch date. Available in some markets but not legally available locally yet.

What This Means In Practice

For most people in SA considering a GLP-1 medication for weight management, Mounjaro is the practical option because it is the one with the right indication, the right availability, and the supporting regulatory approval. This is not a marketing statement, it is the regulatory state in South Africa right now.

For type 2 diabetes specifically, Ozempic remains a valid option alongside Mounjaro. The choice between them depends on goals (weight reduction is a side effect of Ozempic, a primary effect of Mounjaro), tolerability, cost, and availability.

Weight Loss Data Comparison

Direct head to head comparison in obesity (without diabetes) is from the SURMOUNT-5 trial, which compared tirzepatide and semaglutide at maximum doses in adults with obesity over 72 weeks. Results favoured tirzepatide, with mean weight reduction of around 20 percent on tirzepatide compared to around 14 percent on semaglutide.

Indirect comparison across the SURMOUNT and STEP trial programmes shows the same pattern. Tirzepatide produces larger average effects, with comparable side effect profiles. Both are substantially better than placebo or older medications.

Side Effect Comparison

Broadly similar. Both medications cause gastrointestinal effects in the early weeks: nausea, sometimes vomiting, diarrhoea or constipation, indigestion. Both can rarely cause pancreatitis, gallbladder issues, and other less common effects. The titration approach (starting low, stepping up slowly) is used for the same reason in both.

Individual tolerance varies. Some people tolerate one better than the other. Switching is occasionally done when one is poorly tolerated.

Cost Comparison

In SA, Mounjaro and Ozempic sit in similar ranges per month at typical doses. Mounjaro tends to be slightly higher per pen at higher doses but the comparison is not far apart. Both are substantially more expensive than older diabetes medications. Both are sometimes covered by medical aid depending on the plan and the indication.

For weight management specifically, medical aid coverage is variable. Some plans cover GLP-1 medications for obesity treatment, many do not, and the criteria differ by scheme.

Frequently Asked