Mounjaro is the brand name for a medication called tirzepatide. It is made by Eli Lilly, an American pharmaceutical company, and distributed in South Africa by Aspen Pharmacare under a licensing agreement. In SA, Mounjaro is registered with SAHPRA for two uses: type 2 diabetes (approved December 2024) and chronic weight management (approved October 2025).

It is taken as a once weekly injection just under the skin, using a pre-filled pen called the KwikPen. Each pen is single use and contains a single dose.

The Active Ingredient: Tirzepatide

Tirzepatide is what is called a dual incretin agonist. That sentence does a lot of work, so worth unpacking.

Incretins are hormones your gut releases when you eat. They tell your pancreas to release insulin, they tell your brain you are full, and they slow your stomach down so the food sits there longer. The two main incretin hormones are GLP-1 and GIP.

Most newer weight loss and diabetes medications, like Ozempic and Wegovy (both semaglutide), mimic just GLP-1. Tirzepatide mimics both GLP-1 and GIP. That is what makes it different. Acting on two pathways gives, in clinical trials, somewhat stronger effects on both blood sugar and weight than acting on one pathway alone.

Who Makes It And Who Sells It In SA

Eli Lilly developed tirzepatide and holds the global patent. Aspen Pharmacare, a South African company with a marketing agreement with Lilly for sub-Saharan Africa, distributes it locally. This is the same arrangement that brings Mounjaro to South African pharmacies as a proper SAHPRA registered product rather than a parallel import or compounded version.

Buying tirzepatide from overseas websites, including the ones offering 'research' or 'compounded' versions, is risky. SAHPRA has issued warnings about substandard and falsified GLP-1 and GIP-GLP-1 products. The Aspen distributed version, dispensed from a SAPC registered pharmacy with a valid SA prescription, is the only properly regulated route.

What Mounjaro Is Approved For In South Africa

Type 2 diabetes

Approved as an adjunct to diet and exercise for adults with insufficiently controlled type 2 diabetes. Tirzepatide improves blood glucose control and is associated with reduction in body weight in this group.

Chronic weight management

Approved October 2025 as an adjunct to a reduced calorie diet and increased physical activity in adults with:

  • A BMI of 30 kg/m² or more (clinical obesity), or
  • A BMI of 27 kg/m² or more with at least one weight related health condition such as type 2 diabetes, high blood pressure, sleep apnoea, or high cholesterol

It is not approved for cosmetic weight loss in people without these criteria. The SAHPRA approved indication exists because obesity is recognised as a chronic medical condition, not because weight loss in itself is a medical goal.

Find Out If You Qualify

An online consultation walks through eligibility, medical history, and whether Mounjaro is the right choice for you.

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How It Is Different From Older Medications

Several other medications have been used for weight management over the years. Mounjaro sits in the newest class, with several real advantages and a few important downsides.

Vs older appetite suppressants

Stimulant-based appetite suppressants like phentermine work through a different mechanism, are short term only, and have significant cardiovascular risks. Tirzepatide is intended for long term use and works on the body's own hormone signalling.

Vs orlistat (Xenical)

Orlistat works in the gut, blocking fat absorption. It produces modest weight loss with unpleasant gastrointestinal side effects. Tirzepatide acts centrally and metabolically with substantially greater effect.

Vs older GLP-1 medications (liraglutide, Saxenda)

Saxenda (liraglutide) is a daily injection acting on GLP-1 alone. Tirzepatide is weekly and dual pathway. In head to head data, tirzepatide produces stronger effects.

Vs semaglutide (Ozempic, Wegovy)

The closest competitor. Semaglutide is also a weekly injection but acts on GLP-1 only. Comparative trials show tirzepatide produces somewhat greater weight reduction at maximum doses. Both have similar side effect profiles. See our full comparison.

What Mounjaro Does Not Do

  • It does not magic weight away. It works by reducing appetite. If a person eats around the appetite reduction, the medication produces less effect.
  • It does not work without diet and exercise. The SAHPRA approval is specifically as an adjunct to lifestyle changes. People who use it alongside reasonable nutrition and movement get the best results.
  • It is not a short term fix. Studies show weight tends to return after stopping. It is intended as a long term treatment for a chronic condition.
  • It is not for everyone. Pregnancy, certain rare cancers, certain pancreatic and gallbladder conditions, and severe gastrointestinal disease are reasons to avoid it.

Available Doses

Mounjaro KwikPen comes in six single-dose strengths:

  • 2.5 mg (starting dose only)
  • 5 mg
  • 7.5 mg
  • 10 mg
  • 12.5 mg
  • 15 mg (maximum dose)

Treatment starts at 2.5 mg weekly for four weeks to let the body adjust, then increases in 2.5 mg steps every four weeks until reaching either the target therapeutic dose or the maximum tolerated dose. See the dose schedule.

Related Reading

Frequently Asked

Same active ingredient (tirzepatide), same manufacturer (Eli Lilly), different brand names in different countries. In the US, Mounjaro is marketed for diabetes and Zepbound for weight management. In South Africa, Mounjaro is marketed for both indications.

No. Tirzepatide is a peptide medication that mimics two gut hormones, GLP-1 and GIP. It has nothing in common with anabolic or corticosteroid medications.

No. Mounjaro is not insulin. It works by enhancing your body's own insulin release in response to food, and by reducing appetite and slowing stomach emptying.

Tirzepatide is a peptide. Taken as a tablet, stomach acid would digest it before it could work. The weekly subcutaneous injection delivers the medication directly into the body where it remains active.