Mounjaro (Tirzepatide) in Singapore: A Patient Guide

Medically reviewed by Dr Michael Ross MacDonald – The Harley Street Heart & Vascular Centre. Last reviewed: August 2026

Key Facts

  • In a 72-week head-to-head trial (SURMOUNT-5), tirzepatide produced an average body-weight reduction of about 20% versus about 14% for semaglutide.
  • In Singapore, about 9% of adults have diabetes and 12.7% are living with obesity (MOH National Population Health Survey 2024).
  • Trial figures are averages - individual results vary and depend on continued treatment and lifestyle measures.

Overview

Mounjaro is a brand name for tirzepatide, a once-weekly injectable prescription medicine. Unlike Ozempic and Wegovy (which act on GLP-1 alone), tirzepatide is dual-acting - it works on both GLP-1 and GIP receptors, two gut hormones (incretins) involved in regulating blood sugar and appetite.

In Singapore, tirzepatide and related medicines are prescription-only and may be used only after a doctor has assessed you. They are not a standalone solution; they are intended to be used together with dietary changes and physical activity as part of an overall treatment plan. This article explains, in plain terms, how the medicine works, who it may suit, what to expect, and what to discuss with your doctor.

Single-action vs dual-action medicines

Medicines in this group are sometimes described by the hormone pathways they act on. Understanding the difference can help you follow a conversation with your doctor, though it does not tell you which medicine is right for you.

  • Single-action (GLP-1 receptor agonists): semaglutide (the active ingredient in Ozempic and Wegovy) acts on the GLP-1 pathway.
  • Dual-action (GIP and GLP-1 receptor agonists): tirzepatide (Mounjaro) acts on both the GIP and GLP-1 pathways.

GIP and GLP-1 are both incretin hormones - released by the gut after eating - that influence insulin, blood glucose and the feeling of fullness. The combined effect of acting on two pathways is an area of ongoing clinical study, and researchers continue to examine how dual incretin action compares with single-pathway treatment across different groups of patients. A dual-action medicine is not automatically more appropriate for any given person; suitability depends on your individual circumstances.

Mounjaro vs Ozempic and Wegovy

  • Mounjaro (tirzepatide): acts on two hormone pathways (GLP-1 + GIP)
  • Ozempic / Wegovy (semaglutide): act on GLP-1 only

These medicines share some features - they are injectable, taken on a weekly basis, and used alongside lifestyle measures - but they differ in their mechanism. Whether a single- or dual-acting medicine suits you is a clinical decision for your doctor, made after reviewing your medical history, current medicines and treatment goals. This article does not rank one medicine above another.

Why it's used

  • To improve blood glucose control in adults with type 2 diabetes
  • To support weight management in eligible adults (depending on the registered indication and your doctor's assessment)
  • Always alongside diet and physical activity, rather than in place of them

The specific reason a medicine is prescribed depends on its registered indication with the Health Sciences Authority (HSA) and on your individual assessment. Your doctor will explain which indication applies to you and why it is being considered.

How it works

  • Acts on GLP-1 and GIP receptors to support the body's own insulin release when blood glucose is raised
  • Helps reduce the amount of glucagon, a hormone that raises blood sugar
  • Slows the rate at which the stomach empties, which can help you feel full for longer
  • Reduces appetite, which may make it easier to follow dietary changes

Because the medicine works with the body's natural responses to food, several of its effects are linked to eating patterns. This is also why side effects related to digestion are among the more commonly reported ones, particularly when treatment is first started or the dose is increased.

Who may be suitable

Suitability is assessed individually, taking into account your medical history, blood glucose readings, weight, other medicines you take, and your goals. Some people will not be suitable for the medicine, and your doctor may suggest a different approach.

Your doctor will also consider whether you have any conditions that make the medicine unsuitable, any history of digestive or gallbladder problems, and whether you are pregnant, planning a pregnancy or breastfeeding. There is no single profile that fits everyone, which is why a face-to-face assessment matters.

Risks and side effects

As with any medicine, tirzepatide can cause side effects, and not everyone experiences them in the same way.

  • Common: nausea, vomiting, diarrhoea, constipation, reduced appetite
  • Less common: gallbladder problems, pancreatitis (inflammation of the pancreas)
  • Not suitable for people with a personal or family history of medullary thyroid carcinoma or MEN2 (multiple endocrine neoplasia type 2) syndrome

Digestive side effects are often more noticeable early in treatment and may settle over time. Your doctor will explain which symptoms can usually be managed and which ones should prompt you to seek medical attention promptly. If you take other medicines - including those for diabetes that can lower blood sugar - your doctor may need to review them, as combinations can affect your risk of low blood glucose (hypoglycaemia).

Before you start

A consultation confirms eligibility, screens for contraindications and plans the monitoring that will follow. Your doctor will take a history, may arrange blood tests, and will discuss the potential benefits and risks in the context of your situation.

Mounjaro should never be self-sourced, bought from unverified sellers, or shared with anyone else. Medicines obtained outside a proper clinical setting may be unsuitable for you, incorrectly stored, or not what they claim to be. Using a prescription medicine without supervision can be unsafe.

What to expect

Treatment is usually started at a low dose and increased gradually over time. This stepwise approach is intended to limit side effects and help your body adjust. The medicine is given as a once-weekly injection, and your doctor or nurse will explain how and where to inject it, how to store it, and what to do if you miss a dose.

Regular review appointments allow your doctor to check how you are responding, monitor for side effects, and decide whether the dose should stay the same or change. These reviews are an ongoing part of treatment rather than a one-off step.

Monitoring and lifestyle context

Medicines in this group work well when combined with sustained lifestyle measures. Your doctor may discuss balanced eating, regular physical activity, sleep and other habits that support blood glucose control and weight management. Monitoring may include periodic checks of your blood glucose, weight and general wellbeing, and a review of how you are tolerating the medicine.

Lifestyle change is not a backdrop to the medicine - it is part of the treatment. Many of the medicine's intended effects depend on continuing these measures, and the benefits may reduce if treatment or lifestyle support stops. Your doctor will advise on the longer-term plan.

What to discuss with your doctor

  • Your full medical history, including any thyroid, pancreas or gallbladder conditions
  • All medicines and supplements you currently take
  • Whether you are pregnant, planning a pregnancy or breastfeeding
  • Any previous reactions to similar medicines
  • Your goals, and what a realistic plan looks like for you
  • What to do if you experience side effects, and when to seek help

Bringing these points to your consultation can help you and your doctor decide on a plan together.

Results

Effects on blood glucose and weight vary from person to person and depend on continued lifestyle measures alongside the medicine. Any figures quoted should reflect published clinical trial averages rather than individual promises, and results are not guaranteed. Your doctor can give you a realistic sense of what the medicine may and may not do in your situation.

Frequently Asked Questions

Is Mounjaro better than Ozempic?

They work differently - Mounjaro is dual-action (GIP and GLP-1) while Ozempic acts on GLP-1 only. Whether one suits you more than another depends on your individual circumstances and is a decision for your doctor; we do not rank medicines.

Is Mounjaro available in Singapore?

It is a prescription-only medicine. Availability and the conditions it may be prescribed for follow HSA registration, and your doctor will confirm what applies to you.

How is Mounjaro taken?

As a once-weekly injection, usually starting at a low dose that is increased gradually under your doctor's guidance.

Can I stop the medicine once I reach my goal?

This is a decision to make with your doctor. The medicine's effects on blood glucose and weight may lessen if it is stopped, so any change should be planned and supervised rather than done on your own.

Do I still need to change my diet and activity?

Yes. The medicine is intended to be used together with dietary changes and physical activity, not as a replacement for them. These measures are part of the treatment.

What should I do if I experience side effects?

Many digestive side effects are more noticeable early on and may settle over time. Your doctor will explain which symptoms can usually be managed at home and which ones should prompt you to seek medical attention promptly.

Related reading: GLP-1 Medicines; Ozempic; Wegovy

Medical Resources & References

  • Cleveland Clinic - GLP-1 agonists - https://my.clevelandclinic.org/health/treatments/13901-glp-1-agonists
  • SURMOUNT-5 trial (tirzepatide vs semaglutide), NEJM/PubMed - https://pubmed.ncbi.nlm.nih.gov/40353578/
  • MOH - National Population Health Survey 2024 - https://www.moh.gov.sg/others/resources-and-statistics/national-population-health-survey–nphs–2024-report/