If you have been researching weight loss options in Singapore, you may have come across Tirzepatide. This GLP-1/GIP receptor agonist has gained significant attention for its clinical results in weight management.
This guide covers how Tirzepatide works, who is suitable for treatment, what results to expect based on published clinical trials, the side effects to be aware of, and what treatment costs at a Singapore clinic.
All clinical data referenced in this article comes from the SURMOUNT-5 trial, a phase 3b study published in the _New England Journal of Medicine_ (Aronne LJ, et al. N Engl J Med 2025;393:26-36).
Interested in the once-weekly weight loss injection? Speak with our team on WhatsApp to find out if it may be suitable for you.
What Is Tirzepatide and How Does It Work?
Tirzepatide is a once-weekly injectable medication approved by the HSA for weight management. It belongs to a class of drugs called dual incretin receptor agonists.
Most weight loss injections available in Singapore activate only one hormone pathway, the GLP-1 (glucagon-like peptide-1) receptor. This medication is different. It activates two: GLP-1 and GIP (glucose-dependent insulinotropic polypeptide).
This dual mechanism works in several ways:
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- Reduces appetite by acting on hunger-regulating areas in the brain
- Delays gastric emptying, so you feel full longer after meals
- Increases feelings of satiety, reducing the urge to eat between meals
- Reduces cravings for calorie-dense foods
- Lowers body fat mass through direct regulation of fat tissue
The GIP and GLP-1 receptors have overlapping and nonoverlapping expression patterns in the brain and body. Researchers believe this dual agonism is what gives the medication a stronger effect on weight reduction compared to single-pathway treatments.
Bar chart showing percentage of participants achieving weight reduction targets of 10% to 30% with tirzepatide versus semaglutide in the SURMOUNT-5 trial
How Tirzepatide Differs from Other Weight Loss Injections
Several GLP-1 receptor agonist medications are available for weight management in Singapore, including Ozempic (semaglutide) and Saxenda (liraglutide). Here is how Tirzepatide compares:
| Feature | Tirzepatide | Ozempic (semaglutide) | Saxenda (liraglutide) |
| Receptor targets | GLP-1 + GIP (dual) | GLP-1 only | GLP-1 only |
| Injection frequency | Once weekly | Once weekly | Once daily |
| Weight reduction (clinical trial) | -20.2% at 72 weeks | -13.7% at 72 weeks | -8% at 56 weeks |
| Trial reference | SURMOUNT-5 (NEJM 2025) | SURMOUNT-5 (NEJM 2025) | SCALE (NEJM 2015) |
In the SURMOUNT-5 head-to-head trial, 751 adults with obesity (but without type 2 diabetes) were randomised to receive either Tirzepatide or semaglutide at their maximum tolerated doses for 72 weeks. The results showed:
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- Tirzepatide group: -20.2% mean body weight reduction (95% CI: -21.4 to -19.1)
- Semaglutide group: -13.7% mean body weight reduction (95% CI: -14.9 to -12.6)
- Treatment difference: -6.5 percentage points (P<0.001)
In absolute terms, participants lost an average of 22.8 kg, compared with 15.0 kg for those on semaglutide.
These are population averages from a controlled clinical trial. Individual results depend on factors including starting weight, adherence to treatment, diet, and physical activity levels.
Who Is a Suitable Candidate for Tirzepatide?
This is a prescription medication. A doctor will assess whether you are a suitable candidate based on your medical history, current health status, and weight management goals.
General eligibility criteria used in clinical trials:
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- Adults aged 18 years or older
- BMI of 30 or higher (obesity), or BMI of 27 or higher with at least one weight-related health condition such as:
- Hypertension (high blood pressure)
- Dyslipidaemia (abnormal cholesterol levels)
- Obstructive sleep apnoea
- Cardiovascular disease
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- At least one previous unsuccessful attempt at weight reduction through diet and exercise
Who may not be suitable:
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- Individuals with a personal or family history of medullary thyroid carcinoma
- Those with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
- People with a known hypersensitivity to the medication
- Women who are pregnant, planning to become pregnant, or breastfeeding
- Individuals currently taking another GLP-1 receptor agonist medication
- Those who have had bariatric surgery or are planning surgical weight loss treatment
A thorough medical consultation is necessary before starting treatment. Your doctor will review your full medical history, current medications, and health goals to determine if this treatment is appropriate for you.
What to Expect During Treatment
Starting and Adjusting the Dose
Treatment follows a gradual dose escalation schedule to minimise side effects:
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- Weeks 1-4: 2.5 mg per week (starting dose)
- From Week 4: Escalate to 5 mg per week
- From Week 8 onward: Your doctor may increase the dose in increments of 2.5 mg every 4 weeks, up to a maximum of 15 mg per week
Available dose strengths: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg.
The dose is personalised. Not everyone needs to reach the highest dose. Your doctor will find the dose that provides meaningful weight reduction while keeping side effects manageable.
How the Injection Works
The injection is self-administered subcutaneously (under the skin), typically in the abdomen, thigh, or upper arm. You rotate the injection site each week. The injection uses a pre-filled pen and takes less than a minute.
In the SURMOUNT-5 trial, 89.3% of participants reached at least the 15 mg dose, indicating that most patients tolerate the dose escalation well.
Clinic Visits
Your treating doctor will schedule regular follow-up consultations to:
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- Monitor your weight, BMI, and waist circumference
- Assess any side effects
- Adjust your dose as needed
- Review your diet and physical activity
- Check relevant blood markers (blood sugar, cholesterol, blood pressure
Infographic showing tirzepatide dosing schedule from 2.5mg starting dose escalating to maximum 15mg over 20 or more weeks
Expected Results and Timeline
Based on the SURMOUNT-5 trial data published in the _New England Journal of Medicine_:
Weight Reduction
| Timeframe | What to Expect |
| First 4-8 weeks | Appetite changes, early weight reduction during dose escalation |
| 3-6 months | Meaningful weight reduction becomes visible. Most clinical improvement occurs in this window. |
| 72 weeks (full trial duration) | Mean weight reduction of -20.2% (-22.8 kg) with Tirzepatide |
Percentage of Patients Reaching Weight Loss Targets
The SURMOUNT-5 trial reported the following at 72 weeks:
| Weight Reduction Target | Tirzepatide | Semaglutide |
| ≥10% body weight | 81.6% | 60.5% |
| ≥15% body weight | 64.6% | 40.1% |
| ≥20% body weight | 48.4% | 27.3% |
| ≥25% body weight | 31.6% | 16.1% |
| ≥30% body weight | 19.7% | 6.9% |
Nearly half (48.4%) of participants on the dual GLP-1/GIP treatment achieved a weight reduction of 20% or more. By comparison, approximately 1 in 4 participants (27.3%) on semaglutide reached the same target.
Waist Circumference
Participants in the treatment group experienced a mean waist circumference reduction of -18.4 cm, compared with -13.0 cm for semaglutide (P<0.001). Reduced waist circumference is associated with improvements in cardiovascular risk factors.
Blood Pressure
Systolic blood pressure also improved: -10.2 mmHg with the dual agonist versus -7.7 mmHg with semaglutide.
Important Context
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- These results come from a controlled clinical trial with regular medical supervision
- 85% of participants completed the 72-week trial
- Weight reduction was approximately 6 percentage points greater among women than men in both treatment groups
- Individual results vary based on adherence, diet, exercise, and other factors
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- The trial excluded participants with type 2 diabetes
Side Effects and Safety Considerations
Like all medications, Tirzepatide can cause side effects. The SURMOUNT-5 trial reported the following adverse events:
Common Side Effects
| Side Effect | Tirzepatide (n=374) | Semaglutide (n=376) |
| Nausea | 43.6% | 44.4% |
| Constipation | 27.0% | 28.5% |
| Diarrhoea | 23.5% | 23.4% |
| Vomiting | 15.0% | 21.3% |
| Fatigue | 10.4% | 12.2% |
| Injection-site reaction | 8.6% | 0.3% |
| Hair thinning | 8.3% | 6.1% |
| Headache | 7.2% | 7.2% |
Most gastrointestinal side effects are mild to moderate and tend to occur during the dose escalation phase. They typically decrease over time as your body adjusts to the medication.
Treatment Discontinuation Due to Side Effects
In the SURMOUNT-5 trial, 2.7% of participants on the dual agonist discontinued treatment due to gastrointestinal side effects, compared with 5.6% for semaglutide. This suggests the treatment may be better tolerated overall.
Serious Side Effects (Rare)
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- Serious adverse events were reported in 4.8% and 3.5% of participants respectively
- One case of adjudication-confirmed pancreatitis was reported (in the semaglutide group)
- No deaths occurred in either treatment group
- No cases of medullary thyroid cancer or pancreatic cancer were reported
When to Contact Your Doctor
Seek medical attention if you experience:
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- Severe or persistent abdominal pain (possible sign of pancreatitis)
- Signs of an allergic reaction (rash, swelling, difficulty breathing)
- Symptoms of low blood sugar (shakiness, dizziness, confusion)
- Persistent vomiting or inability to keep fluids down
- Any new or worsening symptoms
Cost of Tirzepatide Treatment in Singapore
The medication is prescription-only, and costs vary between clinics in Singapore. Here is a general guide based on current Singapore pricing:
| Component | Estimated Cost |
| Initial consultation | $50 – $150 |
| Starting dose (2.5 mg) | ~$380 – $480 per month |
| Maintenance dose (5-15 mg) | ~$600 – $1,500 per month |
| Follow-up consultations | $50 – $100 per visit |
Factors that affect total cost:
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- Dose level: Higher doses cost more. Not everyone requires the maximum 15 mg dose.
- Treatment duration: Most clinical trials ran for 72 weeks (approximately 18 months).
- Clinic fees: Consultation and monitoring fees vary between practices.
- Additional tests: Blood work and health monitoring add to the total.
Treatment is typically not covered by standard health insurance plans in Singapore. Some clinics offer structured payment plans. Discuss pricing and payment options directly with your treating clinic.
Horizontal bar chart comparing common side effects of tirzepatide and semaglutide including nausea constipation diarrhoea and vomiting from SURMOUNT-5 trial data
Tips for Getting the Most from Your Treatment
The medication works alongside, not instead of, healthy lifestyle habits. The SURMOUNT-5 trial participants received counselling on nutrition and physical activity throughout the study. Here are evidence-based ways to support your treatment:
Nutrition
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- Focus on protein-rich meals to preserve muscle mass during weight loss
- Eat slowly and stop when you feel satisfied (the injection will amplify your fullness signals)
- Stay hydrated. Aim for at least 2 litres of water daily.
- Reduce calorie-dense, highly processed foods
- If nausea is an issue during dose escalation, eat smaller, more frequent meals
Physical Activity
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- Aim for 150 minutes of moderate activity per week (walking, swimming, cycling)
- Include resistance training 2-3 times per week to maintain lean muscle
- Start gradually and increase intensity as your weight decreases and fitness improves
Monitoring
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- Weigh yourself consistently (same time, same conditions) once per week
- Track waist circumference monthly
- Keep a food journal during the first few weeks to identify patterns
- Attend all scheduled follow-up appointments with your doctor
Long-Term Maintenance
The clinical evidence suggests that weight management with this treatment is most effective as a sustained programme. Stopping treatment may lead to weight regain, similar to what has been observed with other GLP-1 medications. Discuss a long-term plan with your doctor.
Common Myths About Weight Loss Injections
“These injections are a shortcut that replaces diet and exercise.”
Not accurate. In clinical trials, all participants received lifestyle counselling alongside the medication. The medication helps manage the hormonal and metabolic factors that make sustained weight loss difficult, but it works alongside healthy habits, not as a replacement for them.
“You will regain all the weight once you stop.”
Weight regain is possible after discontinuing usage of any weight loss pens. This is why ongoing medical supervision and a long-term maintenance plan are important.
“Weight loss injections are dangerous.”
In the SURMOUNT-5 trial involving 751 participants over 72 weeks, there were no deaths in either treatment group. Most side effects were gastrointestinal, mild to moderate, and decreased over time. As with any prescription medication, risks should be discussed with your doctor in the context of your individual health profile.
“Only people with diabetes should use these medications.”
This medication is approved for weight management in adults with obesity or overweight with weight-related health conditions. The SURMOUNT-5 trial specifically excluded participants with type 2 diabetes, demonstrating its effectiveness independent of diabetes.
Questions to Ask Your Doctor Before Starting
If you are considering this treatment for weight management, here are questions to bring to your consultation:
- Am I a suitable candidate based on my BMI, health conditions, and medical history
- What dose should I start on, and how will we determine my maintenance dose?
- How will we monitor my progress, and how often should I come in for follow-ups?
- What side effects should I watch for, and when should I contact the clinic?
- How long should I expect to be on treatment to achieve my weight loss goals?
- What happens if I want to stop treatment? Is there a tapering process?
- Are there any medications I am currently taking that could interact with this medication?
- What dietary changes would you recommend alongside treatment?
- What is the total estimated cost of treatment over the recommended duration? A good consultation should feel like a conversation, not a sales pitch. Your doctor should explain your options clearly and give you time to make an informed decision.
References
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- Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide once weekly for the treatment of obesity. _N Engl J Med_. 2022;387:205-16. (SURMOUNT-1)
- Tirzepatide prescribing information (PI). Singapore. Date of revision: 10 June 2025.
- ClinicalTrials.gov: SURMOUNT-5 (NCT05822830)
This article is for educational purposes only and does not constitute medical advice. Consult a qualified doctor to determine if tirzepatide is suitable for your individual health needs.
Frequently Asked Questions
Can I take this medication if I have diabetes?
Mounjaro is also approved for type 2 diabetes management under a different indication. However, the weight management dosing and diabetes dosing may differ. If you have diabetes, your doctor will determine the appropriate treatment plan. The SURMOUNT-5 trial data referenced in this article specifically studied participants without type 2 diabetes.
What happens when I stop treatment?
Weight regain is possible after stopping treatment, as with any weight management medication like Mounjaro. Your doctor will discuss a long-term plan, which may include continued treatment at a maintenance dose, lifestyle modifications, or a combination of approaches.
Do I need to inject myself?
Yes. It is administered as a once-weekly subcutaneous injection using a pre-filled pen. Your doctor or nurse will demonstrate the technique during your first visit. Most patients find the self-injection straightforward after the first attempt.
Is Tirzepatide safe?
The SURMOUNT-5 trial reported no deaths in either treatment group over 72 weeks. Most side effects were gastrointestinal (nausea, constipation, diarrhoea), mild to moderate in severity, and decreased over time. 85% of participants completed the full trial. All medications carry some risk, and your doctor will assess whether Mounjaro benefits outweigh the risks for your individual situation.
How much weight can I expect to lose?
In the SURMOUNT-5 trial, participants lost an average of 22.8 kg (20.2% of body weight) over 72 weeks. 81.6% achieved at least 10% weight loss, and 48.4% achieved at least 20%. Individual results depend on starting weight, dose, adherence, diet, and physical activity. Do seek doctors advice before taking Mounjaro.
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