Wegovy vs Mounjaro

If you are choosing between modern weight management medications in South Africa in 2026, the question is most often Wegovy or Mounjaro. Both are SAHPRA approved for chronic weight management. Both are weekly injections. Both have strong trial data. They differ in some important ways, and the right choice depends on more than the average trial result.

The Comparison Table

The Key Mechanism Difference

Wegovy mimics one hormone, GLP-1. Mounjaro mimics two, GLP-1 and GIP. Both hormones are made by the gut in response to food. Both regulate appetite, insulin response, and gastric emptying. GIP also affects how fat tissue handles energy.

In theory, acting on two hormones should produce stronger effects than acting on one. In practice, the trial data confirms this. Mounjaro produces around 5 percentage points more weight reduction on average at maximum dose compared to Wegovy.

For most people most days, the experience of the two medications is similar. Both reduce appetite. Both slow gastric emptying. Both make eating less easier. The difference shows up in average outcomes at maximum dose over a year or more.

The Head To Head Data

The SURMOUNT-5 trial directly compared tirzepatide and semaglutide in adults with obesity over 72 weeks. Mean weight reduction was around 20 percent on tirzepatide and around 14 percent on semaglutide. Individual response varies, but the average favoured tirzepatide.

This is one trial. The broader STEP and SURMOUNT trial programmes (separate trials, comparable designs) show similar patterns. Tirzepatide produces somewhat larger average effects.

Side Effects Compared

Broadly similar profiles. The same gastrointestinal effects in similar proportions in the early weeks. Most studies show no significant difference in side effect rates between the two at comparable dose stages.

Individual variation matters. Some people tolerate one better than the other. Some find one suppresses appetite more strongly. There is no reliable way to predict which will suit a particular person until you try.

Cost Comparison In South Africa

Until March 2026, Mounjaro and Wegovy sat at broadly similar SA price points. Then Novo Nordisk announced substantial price reductions on Wegovy, with the lowest dose dropping from R3,090 to R1,873.

Current rough comparison:

• Starting Wegovy (0.25 mg): around R1,873/month
• Starting Mounjaro (2.5 mg): around R3,400-R3,600/month
• Maintenance Wegovy (2.4 mg): around R3,746/month
• Maintenance Mounjaro (10 mg or higher): around R5,000+/month

At the starting dose, Wegovy is now meaningfully cheaper. Through the titration months this difference compounds. At maintenance the gap narrows but Wegovy remains somewhat cheaper for most.

For people who respond well at lower Wegovy doses (1 mg or 1.7 mg rather than needing 2.4 mg), the cost picture is even more favourable.

Cardiovascular Evidence

Wegovy has stronger cardiovascular outcome data so far. The SELECT trial established a 20 percent reduction in major adverse cardiovascular events in people with established cardiovascular disease and BMI of 27 or more. Wegovy is approved specifically for this indication.

Mounjaro has emerging cardiovascular data but no formal cardiovascular indication yet. The SURPASS-CVOT trial reported in 2025 with positive results, but the regulatory updates are still in progress.

For someone with established cardiovascular disease, this is a real consideration favouring Wegovy at present.

Adolescent Use

Wegovy is approved for adolescents aged 12 and older with obesity. Mounjaro is approved for adults only. For families considering medication for an adolescent, Wegovy is the only available option.

Which Suits Whom

Wegovy leans favoured for

• People prioritising cost (particularly with the March 2026 price reductions)
• People with established cardiovascular disease
• Adolescents aged 12 and older
• People wanting the more established (longer track record) GLP-1 medication
• People who do not need maximum possible weight reduction

Mounjaro leans favoured for

• People needing maximum possible weight reduction
• People with type 2 diabetes (where Mounjaro is also SAHPRA approved)
• People who have not responded adequately to GLP-1 only medications
• People for whom the cost difference is not the limiting factor

For most people, both are reasonable

The differences matter at the margins. For someone in the middle of the eligibility criteria without strong reasons either way, both work. The consulting doctor's recommendation often comes down to cost, availability, and specific medical history.

Practical Note On Switching

Switching between Wegovy and Mounjaro is occasionally done, usually because:

• One is poorly tolerated
• Response is inadequate at maximum dose
• Cost differences become limiting
• Supply issues with one but not the other

The transition starts the new medication at a low dose and titrates up. Doses are not directly comparable because the molecules differ. The treating doctor handles the switch.

Frequently Asked