Two names dominate the GLP-1 conversation in South Africa right now: Ozempic and Mounjaro. Both are injectable medications that help with blood sugar control and weight loss, both are available with a prescription from licensed pharmacies, and both have seen explosive demand.

But they're not the same drug. Understanding the differences can help you have a more informed conversation with your doctor about which option might be right for you.

The Basics: Different Drugs, Different Mechanisms

Ozempic contains semaglutide, manufactured by Novo Nordisk. It's a GLP-1 receptor agonist — meaning it mimics the single gut hormone GLP-1 to regulate blood sugar, slow digestion, and reduce appetite.

Mounjaro contains tirzepatide, manufactured by Eli Lilly and marketed in South Africa by Aspen Pharmacare. It's a dual GIP/GLP-1 receptor agonist — meaning it mimics two gut hormones: GLP-1 and GIP (glucose-dependent insulinotropic polypeptide). This dual mechanism is what sets it apart.

Both are administered as once-weekly injections using a pre-filled pen.

What Are They Registered For in South Africa?

Ozempic is registered with SAHPRA for the treatment of type 2 diabetes. It is widely prescribed off-label for weight management, though its formal registration is for blood sugar control.

Novo Nordisk also launched Wegovy in South Africa in 2025 — this contains the same active ingredient (semaglutide) but at higher doses and is specifically registered for weight management.

Mounjaro was launched in South Africa in December 2024 for type 2 diabetes. In October 2025, SAHPRA approved it for weight management as well, making it one of the few GLP-1 medications in the country with formal approval for both indications.

Weight Loss: What Does the Evidence Show?

Both medications have demonstrated significant weight loss in clinical trials, but the results differ.

In the STEP trials, patients taking semaglutide (at the higher Wegovy dose of 2.4mg weekly) achieved average weight loss of around 15% of their body weight over 68 weeks.

In the SURMOUNT trials, patients taking tirzepatide at the highest dose achieved average weight loss of approximately 22% of their body weight over 72 weeks — making it the most effective pharmaceutical weight loss intervention studied to date.

Head-to-head trials are still ongoing, but based on the available evidence, tirzepatide appears to produce greater weight loss on average. That said, individual responses vary significantly, and the "best" medication for any given person depends on multiple clinical factors.

Side Effect Profiles

The side effect profiles are broadly similar, since both drugs affect the gastrointestinal system through similar mechanisms.

Common side effects for both include nausea, vomiting, diarrhoea, constipation, abdominal pain, and reduced appetite. These are typically most pronounced when starting treatment and during dose increases, and tend to improve as the body adjusts.

Both carry warnings about rare but serious risks including pancreatitis, gallbladder problems, and potential thyroid concerns based on animal studies. Both are contraindicated in patients with a history of medullary thyroid carcinoma or MEN2.

Some clinical data suggests that tirzepatide may have a slightly different gastrointestinal profile than semaglutide at equivalent efficacy levels, but this is still being studied. Your doctor can help you weigh these considerations based on your personal health history.

Dosing and Titration

Both medications follow a gradual dose-escalation schedule to minimise side effects.

Ozempic starts at 0.25mg weekly for the first four weeks, then increases to 0.5mg. It can be further increased to 1mg or 2mg depending on the clinical response.

Mounjaro starts at 2.5mg weekly for four weeks, then increases to 5mg. Further increases to 7.5mg, 10mg, 12.5mg, and 15mg are available depending on response and tolerability.

The wider dose range available with Mounjaro gives doctors more flexibility to fine-tune the treatment, which can be particularly useful for patients who respond at moderate doses without needing the maximum.

Cost in South Africa

Both medications are expensive, though pricing varies by dose:

Ozempic: Approximately R1,700–R3,200 per month depending on the prescribed dose.

Mounjaro: Approximately R3,000–R6,000 per month depending on the dose.

Wegovy: Approximately R3,000–R6,000 per month.

Medical aid coverage remains limited for both. Most schemes will provide some coverage when prescribed for type 2 diabetes with certain clinical criteria, but coverage for weight management alone is rare. Obesity is not currently classified as a prescribed minimum benefit in South Africa.

Which One Should You Choose?

This isn't a decision to make based on an article — it's a conversation to have with your doctor. Factors that influence the choice include:

  • Whether your primary goal is blood sugar management, weight loss, or both
  • Your medical history and any contraindications
  • How you respond to the starting doses
  • Cost considerations and what your medical aid will cover
  • Previous experience with GLP-1 medications (if applicable)

Both Ozempic and Mounjaro are well-supported by clinical evidence and represent a genuine step forward in the treatment of metabolic disease and obesity. The right choice is the one that fits your specific clinical picture, goals, and circumstances — and that's something only a qualified doctor can properly assess.

What About Generics?

Key patents for semaglutide are beginning to expire in several countries, and generic versions are expected to enter the global market starting in 2026. Some analysts project that generic semaglutide could reach South Africa by 2027, which would significantly reduce costs.

Tirzepatide patents extend further into the 2030s, so generic versions of Mounjaro are likely still years away.

For now, both medications remain available only as branded products from their respective manufacturers.