Mounjaro Singapore: The New Weight Loss Injection Explained

This guide covers everything you need to know.

What Is Mounjaro (Tirzepatide)?

Mounjaro is an injectable prescription medication developed by Eli Lilly. Its active ingredient, tirzepatide, works differently from first-generation GLP-1 receptor agonists like semaglutide (Ozempic/Wegovy). While semaglutide activates one receptor (GLP-1), tirzepatide is a dual GIP/GLP-1 receptor agonist — it simultaneously activates both the glucagon-like peptide-1 (GLP-1) receptor and the glucose-dependent insulinotropic polypeptide (GIP) receptor.

This dual mechanism is significant. GIP receptors in fat tissue appear to enhance the weight-loss effects of GLP-1 signalling, and the combination produces a more powerful metabolic response than either pathway alone.

Tirzepatide was originally approved by the US FDA for Type 2 diabetes management in 2022. It subsequently gained approval for chronic weight management (as Zepbound in the US) in 2023, after clinical trial data showed unprecedented weight-loss results in people without diabetes.

What Do the Clinical Trials Show?

The landmark trial for tirzepatide in obesity is SURMOUNT-1, published in the New England Journal of Medicine in 2022 (Jastreboff et al., NEJM 2022;387:205–216).

SURMOUNT-1 key findings: - 2,539 adults with obesity (BMI ≥ 30) or overweight (BMI ≥ 27) with at least one weight-related complication enrolled - Participants received tirzepatide 5 mg, 10 mg, or 15 mg weekly, or placebo, for 72 weeks - Mean body weight reduction at 72 weeks: - 5 mg dose: −15.0% body weight - 10 mg dose: −19.5% body weight - 15 mg dose: −20.9% body weight - Placebo: −3.1% body weight - At the highest dose, 57% of participants achieved ≥20% body weight reduction - All tirzepatide groups showed statistically significant reductions in waist circumference, blood pressure, fasting glucose, and lipid profiles

To put that in perspective: for a 90 kg individual, a 20.9% reduction represents approximately 18.8 kg of weight loss over 72 weeks — well beyond what most lifestyle interventions alone can achieve.

These results positioned tirzepatide as potentially the most effective pharmacological weight-loss treatment currently available.

How Does Tirzepatide Compare to Semaglutide?

Semaglutide (the active ingredient in Ozempic and Wegovy) was previously considered the gold standard for GLP-1-mediated weight loss. The STEP 1 trial (Wilding et al., NEJM 2021;384:989–1002) demonstrated a mean weight reduction of 14.9% at 68 weeks on semaglutide 2.4 mg weekly.

Head-to-head data from the SURPASS-2 trial further confirmed that tirzepatide outperforms semaglutide on weight loss outcomes across all doses tested.

Both are effective. Tirzepatide tends to produce greater weight reduction on average, though individual responses vary. Your doctor will assess which option suits your health profile.

How Is Mounjaro Administered?

Tirzepatide is administered as a once-weekly subcutaneous injection, typically into the abdomen, thigh, or upper arm. It comes in pre-filled auto-injectors (pens) across multiple doses:

• Starting dose: 2.5 mg once weekly for 4 weeks
• Titration: Dose is gradually increased every 4 weeks (2.5 mg → 5 mg → 7.5 mg → 10 mg → 12.5 mg → 15 mg)
• The slow titration schedule helps minimise gastrointestinal side effects during the adjustment period

Most patients are shown how to self-inject by their prescribing doctor or nurse. The injection itself is quick and uses a very fine needle.

What Are the Side Effects?

Like all GLP-1-class medications, tirzepatide's most common side effects are gastrointestinal:

• Nausea (most common, especially during dose escalation)
• Diarrhoea or constipation
• Vomiting
• Reduced appetite (this is also part of its mechanism)
• Abdominal discomfort

These side effects are typically mild to moderate and tend to ease as your body adjusts. Eating smaller meals, avoiding high-fat or high-sugar foods, and staying hydrated can help.

Less common but important side effects to discuss with your doctor: - Hypoglycaemia (low blood sugar), particularly if combined with insulin or sulfonylureas - Pancreatitis (rare; stop and seek medical attention if you experience severe persistent abdominal pain) - Gallbladder disease (cholecystitis) - Injection site reactions

Contraindications: - Personal or family history of medullary thyroid carcinoma (MTC) - Multiple Endocrine Neoplasia syndrome type 2 (MEN 2) - Pregnancy or breastfeeding

This is why tirzepatide must only be prescribed after a proper medical consultation.

Is Mounjaro (Tirzepatide) Available in Singapore?

Yes. Tirzepatide is available in Singapore under the Health Sciences Authority (HSA) licensing framework. Like all prescription weight-management medications in Singapore, it must be prescribed by a licensed doctor following a medical assessment. It is not available over-the-counter or through non-medical channels.

Accessing it through legitimate channels means: 1. A medical consultation (in-person or via licensed telehealth) 2. A doctor's assessment of your BMI, health history, and medication suitability 3. A prescription issued by a registered Singapore doctor 4. Medication dispensed by a licensed pharmacy

Who Is a Candidate for Tirzepatide in Singapore?

Tirzepatide is typically considered for adults who meet criteria such as:

• BMI ≥ 30 (obesity), or
• BMI ≥ 27 with at least one weight-related comorbidity (e.g., Type 2 diabetes, hypertension, dyslipidaemia, obstructive sleep apnoea)
• Have not achieved sufficient results through diet and exercise alone
• Do not have contraindications to the medication

Your doctor will make the final determination based on your individual health profile.

What About Cost?

Pricing for tirzepatide in Singapore varies by clinic and dose. As with most novel prescription medications, it represents a meaningful monthly cost. Many patients find that the health improvements — reduced need for other medications, improved metabolic markers, reduced joint stress — make it a worthwhile investment. Your doctor can advise on current pricing during your consultation.

How to Access Mounjaro in Singapore Safely

With the rise of interest in GLP-1 medications, there has unfortunately also been a rise in counterfeit and unregulated products. Never source tirzepatide from social media, grey-market suppliers, or unverified online platforms. Counterfeit injectables pose serious health risks.

The safe route: consult a licensed doctor who will assess your suitability, prescribe the correct dose, and guide you through treatment with proper monitoring.

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Ready to find out if Mounjaro is right for you?

Noah is a licensed telehealth platform offering prescription weight management consultations in Singapore. Our doctors assess your health profile, discuss your options — including tirzepatide and semaglutide — and provide ongoing support throughout your treatment.

Start your consultation at ofnoah.sg →

Mounjaro (tirzepatide) is a prescription-only medication. This article is for informational purposes only and does not constitute medical advice. Consult a licensed doctor to determine if it is appropriate for you.