In Singapore, doctor-prescribed weight loss injection pens have become an important option for individuals seeking medical support for weight management. These treatments include once-weekly and daily GLP-1 receptor agonist injections, which are internationally recognised and available under various brand names.

These prescription pens deliver medications such as semaglutide, tirzepatide, and liraglutide. By acting on appetite regulation and metabolic pathways, these treatments may support weight reduction in suitable patients under medical supervision.

Weekly injection pens containing semaglutide are available in both standard (0.25–1mg) and higher-dose (up to 2.4mg) versions. The dual agonist injection pen with tirzepatide is a more recent development, while the daily liraglutide injection pen is a well-established option for weight management.

This guide provides an overview of GLP-1 and dual agonist weight loss injection pens in Singapore, including their mechanisms of action, who may be eligible for treatment, and what to expect during the process.

What Are GLP-1 and Dual Agonist Weight Loss Injection Pens?

GLP-1 and dual agonist weight loss injection pens are doctor-prescribed medications used in Singapore to assist with medical weight management in adults with overweight or obesity. 

These injectable treatments are administered as either once-weekly or daily injections, depending on the medication, and act on hormonal pathways that regulate appetite, satiety, and metabolism.

Several active ingredients are used in these pens, including semaglutide, tirzepatide, and liraglutide. All require a medical consultation, prescription, and ongoing monitoring to ensure safety and suitability.

Prescription Options Available in Singapore

Prescription weight loss injection pens in Singapore are available as both weekly and daily options. The main types are:

• Once-weekly pens containing semaglutide, suitable for both diabetes and weight management at various doses.
  
• Once-weekly pens containing tirzepatide, a dual agonist option for enhanced weight loss support.
  
• Daily pens containing liraglutide, which may be preferred or required for certain patients.
  

Each option is chosen based on clinical assessment and individual needs. For dosing details and specific indications, see the section below.

Overview of Key Active Ingredients

• Semaglutide: A GLP-1 receptor agonist used in both weekly and high-dose injection pens for medical weight loss.
  
• Tirzepatide: A dual agonist (GLP-1 and GIP) administered as a once-weekly injection for weight management.
  
• Liraglutide: A daily GLP-1 receptor agonist injection used for long-term weight control.
  

These ingredients work by supporting appetite regulation, calorie reduction, and improved metabolic control.

How Do Prescription Weight Loss Injection Pens Work?

Weight loss injection pens help reduce body weight by targeting hormones that influence hunger, fullness, and energy balance. These mechanisms make them effective as part of a comprehensive, medically supervised weight management plan.

Mechanism of Action – Appetite, Satiety, and Metabolic Effects

GLP-1 receptor agonists such as semaglutide and liraglutide mimic the effects of the natural GLP-1 hormone, increasing satiety, reducing hunger, and slowing gastric emptying. This can result in decreased caloric intake and gradual, sustained weight loss. 

Dual agonist injections with tirzepatide activate both GLP-1 and GIP pathways, providing an additional effect on appetite and glucose control, which may lead to greater weight reduction for some individuals.

Differences Between Weekly and Daily Injection Pens

• Once-weekly injection pens (semaglutide, tirzepatide): Administered once a week for convenience, these formulations suit many patients seeking a low-maintenance weight loss option.
  
• Daily injection pens (liraglutide): Require consistent, daily administration. This approach may be preferable for individuals based on clinical needs or response to therapy.
  

The most appropriate dosing schedule is determined by a doctor during the initial assessment and follow-up consultations.

Types of Prescription Weight Loss Injection Pens in Singapore

This section details each type of weight loss injection pen available in Singapore, including specific dosing, titration protocols, and unique considerations for each medication.

Once-Weekly Semaglutide Injection Pen – Standard Dose (0.25mg to 1mg)

The once-weekly semaglutide pen is prescribed at standard doses ranging from 0.25mg to 1mg. It is indicated for both type 2 diabetes and weight management. 

Treatment typically starts at the lowest dose, with gradual increases based on clinical response and tolerance. This pen offers a familiar and convenient weekly regimen for many patients.

Once-Weekly Semaglutide Injection Pen – High Dose (Up to 2.4mg for Weight Loss)

A high-dose version of the once-weekly semaglutide pen is specifically indicated for weight management in adults with overweight or obesity. 

Dosing begins at 0.25mg and is increased over several weeks up to a maximum of 2.4mg weekly, as guided by your doctor. This escalation protocol is designed to minimise side effects while achieving optimal results.

Once-Weekly Dual Agonist Injection Pen (Tirzepatide, GLP-1 + GIP)

The tirzepatide injection pen is a next-generation, dual agonist therapy targeting both GLP-1 and GIP receptors for enhanced weight loss support. 

It is available in multiple dosing strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, and 15mg. 

Treatment usually starts at the lowest available dose, with titration at regular intervals to achieve the desired therapeutic effect while monitoring for tolerability and efficacy.

Daily GLP-1 Injection Pen (Liraglutide)

The daily liraglutide injection pen is administered once daily and is suitable for adults requiring a more frequent dosing schedule. 

Dosing is initiated at a lower strength and gradually increased based on patient response. This established GLP-1 agonist is chosen for patients who may not tolerate weekly injections or who respond best to a daily regimen.

Who Is Suitable for Prescription Weight Loss Injection Pens?

Prescription weight loss injection pens—including those containing semaglutide, tirzepatide, or liraglutide—are not suitable for everyone. These treatments are intended for adults who meet specific clinical criteria and should only be started after a comprehensive medical assessment by a qualified doctor in Singapore.

Eligibility Criteria for GLP-1 and Dual Agonist Injections

Weight loss injection pens with semaglutide, tirzepatide, or liraglutide may be considered for adults who:

• Have a body mass index (BMI) of 27 kg/m² or higher with at least one weight-related health condition (such as high blood pressure, high cholesterol, or type 2 diabetes), or
  
• Have a BMI of 30 kg/m² or higher, regardless of associated medical conditions,
  
• Have not achieved or maintained significant weight loss through lifestyle modifications alone.
  

These criteria apply to all GLP-1 and dual agonist treatments, including once-weekly semaglutide or tirzepatide injections and daily liraglutide injections.

Medical Assessment and Contraindications

Before prescribing semaglutide, tirzepatide, or liraglutide injection pens, your doctor will conduct a detailed medical evaluation. This includes a review of your health history, current medications, and any relevant risk factors. These prescription treatments are generally not recommended for:

• Pregnant or breastfeeding individuals,
  
• Patients with a history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2,
  
• Those with severe gastrointestinal disease or pancreatitis,
  
• Individuals with a BMI below 27 kg/m².
  

Your doctor will also consider any other health conditions that may affect the safety of using a GLP-1 or dual agonist medication.

Ongoing Monitoring and Follow-Up

Patients prescribed semaglutide, tirzepatide, or liraglutide for weight loss will require regular follow-up appointments. Your doctor will monitor your progress, review any potential side effects, and adjust your dosing as needed to ensure continued safety and effectiveness of the treatment.

Treatment Process – What to Expect with Weight Loss Injection Pens

Understanding the treatment process helps patients prepare for safe and effective weight loss using prescription injection pens, including those containing semaglutide, tirzepatide, or liraglutide.

Medical Consultation and Assessment

Your weight management journey begins with a medical consultation at a licensed clinic in Singapore. During this appointment, your doctor will review your medical history, calculate your body mass index (BMI), and discuss your weight loss goals. 

Suitability for a GLP-1 injection pen containing semaglutide or liraglutide, or a dual agonist injection pen containing tirzepatide, is determined based on clinical guidelines and your individual needs.

Prescription, Dosing, and Titration

If eligible, your doctor will prescribe the most appropriate injection pen and provide clear instructions on self-administration. For semaglutide and tirzepatide, treatment usually starts at a lower dose with gradual titration over several weeks to reach the maintenance dose. 

Liraglutide, as a daily GLP-1 injection, also follows a gradual dose escalation to enhance tolerability. You will receive training on injection technique, the recommended dosing schedule (weekly for semaglutide or tirzepatide, daily for liraglutide), and safe storage of your medication.

Monitoring Progress and Follow-Up

Regular follow-up appointments are required to monitor your weight loss progress, check for side effects, and make any necessary adjustments to your dosing. Your doctor will review your response to semaglutide, tirzepatide, or liraglutide, and assess changes in weight and metabolic health. 

Ongoing support and medical supervision are key to maximising the benefits and safety of your treatment.

Lifestyle Support and Adjunct Measures

Combining GLP-1 or dual agonist injection therapy with a reduced-calorie diet, increased physical activity, and healthy lifestyle habits further supports long-term weight loss. 

Your doctor may provide or recommend additional resources for nutrition and exercise counselling to help you achieve and sustain your goals.

Clinical Evidence and Results for GLP-1 and Dual Agonist Injections

Numerous clinical trials and real-world studies have demonstrated the effectiveness of GLP-1 receptor agonists and dual agonist injections, such as semaglutide, tirzepatide, and liraglutide, for medical weight management in adults with overweight or obesity.

Key Clinical Trials and Study Findings

• Semaglutide: Large international studies, including the STEP trials, have shown that once-weekly semaglutide injections can lead to average weight loss of 10–15% of initial body weight over 68 weeks, when combined with diet and exercise.
  
• Tirzepatide: The dual agonist tirzepatide has demonstrated even greater weight loss in the SURMOUNT clinical trials, with some participants achieving reductions of up to 20% of initial body weight at higher doses over a similar period.
  
• Liraglutide: Clinical trials, such as the SCALE studies, report that daily liraglutide injections support an average weight loss of 5–8% of initial body weight, also when combined with lifestyle changes.

References

1. SURMOUNT-4 Study (Tirzepatide for Obesity, 2024, JAMA):
   
2. STEP-1 Study (Once-Weekly Semaglutide for Weight Management, 2021, NEJM):
   
3. SCALE Study (Liraglutide for Weight Management, 2015, NEJM):
   

Expected Results in Real-World Practice

While results can vary from person to person, many patients in Singapore have achieved significant, sustained weight loss with semaglutide, tirzepatide, or liraglutide injections as part of a comprehensive doctor-supervised programme. 

Weight reduction is typically gradual, with the greatest changes seen in the first six to twelve months of treatment.

Ongoing follow-up with your doctor is essential to maximise benefits, monitor side effects, and support long-term success. Combining medication with dietary adjustments and increased physical activity is recommended for best outcomes.

Side Effects and Safety Information for Weight Loss Injection Pens

Understanding the potential side effects and safety considerations of prescription weight loss injection pens—such as semaglutide, tirzepatide, and liraglutide—is essential for patients considering GLP-1 or dual agonist therapies in Singapore. 

Careful medical supervision and regular follow-up help minimise risks and ensure the safe use of these medications.

Common Side Effects of Semaglutide, Tirzepatide, and Liraglutide

Most patients experience mild to moderate side effects when starting GLP-1 or dual agonist weight loss injections. The most frequently reported include:

• Nausea
  
• Vomiting
  
• Diarrhoea or constipation
  
• Loss of appetite
  
• Mild abdominal discomfort or bloating
  

These side effects are usually temporary and tend to improve as the body adjusts to the medication. Starting at a lower dose and gradually increasing the dosage can help minimise these symptoms.

Rare But Serious Risks

Although uncommon, some patients may experience more serious side effects, including:

• Severe abdominal pain (which may indicate pancreatitis)
  
• Signs of allergic reaction (such as rash, swelling, or difficulty breathing)
  
• Persistent vomiting or dehydration
  
• Gallbladder issues (such as gallstones)
  

GLP-1 and dual agonist weight loss injections are generally not recommended for individuals with a personal or family history of medullary thyroid carcinoma, multiple endocrine neoplasia syndrome type 2, or a history of severe gastrointestinal disease. 

It is important to inform your doctor about all your medical conditions before starting treatment.

Safety Monitoring and When to Seek Medical Attention

Patients prescribed semaglutide, tirzepatide, or liraglutide injection pens will have regular follow-up appointments to monitor for side effects, review lab results, and assess overall response to treatment. 

Always contact your doctor immediately if you experience severe abdominal pain, symptoms of an allergic reaction, or any new or concerning side effects during treatment.

Prompt reporting and medical evaluation help ensure that potential complications are identified early and managed appropriately.

How to Get Started with Prescription Weight Loss Injection Pens in Singapore

Starting prescription weight loss injection therapy, such as GLP-1 or dual agonist injections (semaglutide, tirzepatide, or liraglutide), requires careful medical supervision to ensure safety and optimal results. Here’s what to expect when beginning your treatment journey in Singapore:

Step 1 – Book a Medical Consultation

Your first step is to schedule an appointment with a doctor experienced in weight management. During the consultation, your medical history, body mass index (BMI), and previous weight loss attempts will be reviewed to determine eligibility for a prescription weight loss injection pen.

Step 2 – Comprehensive Assessment and Prescription

If you meet clinical criteria, your doctor will conduct a thorough evaluation to select the most appropriate medication—such as a once-weekly semaglutide or tirzepatide injection, or a daily liraglutide injection. The prescription will include a starting dose and a titration plan based on your individual needs and safety profile.

Step 3 – Patient Education and Self-Administration Training

You will receive detailed instructions on how to use your injection pen, including safe injection techniques, storage requirements, and a dosing schedule. The clinic team will demonstrate the process and answer any questions to ensure you are comfortable and confident in self-administration.

Step 4 – Ongoing Follow-Up and Support

After starting treatment, you will have regular follow-up visits to monitor progress, adjust dosing if needed, and address any side effects or concerns. Ongoing medical supervision helps maximise weight loss results while maintaining safety.

How to Book a Consultation in Singapore

To begin your weight loss journey with a prescription injection pen, book a consultation with our clinic today. Our doctor will provide a personalised assessment and guide you through every step of the process.

Comparing GLP-1 and Dual Agonist Weight Loss Injection Options

Understanding the differences between available GLP-1 and dual agonist weight loss injection pens helps patients and clinicians select the most suitable treatment. 

The main injectable medications prescribed in Singapore for medical weight management are semaglutide, tirzepatide, and liraglutide.

Semaglutide vs Tirzepatide vs Liraglutide – Key Differences

• Mechanism of Action:
  
  • Semaglutide and liraglutide are GLP-1 receptor agonists that help regulate appetite, food intake, and blood sugar levels.
    
  • Tirzepatide is a dual agonist that acts on both GLP-1 and GIP receptors, providing an additional pathway for appetite and metabolic regulation.
    
• Dosing Frequency:
  
  • Semaglutide and tirzepatide are administered once weekly.
    
  • Liraglutide is injected once daily.
    
• Approved Indications:
  
  • All three medications are approved for weight management in adults who meet clinical criteria, but their specific regulatory approvals and dosing recommendations may differ.
    

Expected Weight Loss and Clinical Results

• Semaglutide:
  The STEP clinical trials have shown that once-weekly semaglutide can help patients achieve an average weight loss of 10–15% of their initial body weight over 68 weeks, when combined with lifestyle intervention.
  
• Tirzepatide:
  In the SURMOUNT studies, tirzepatide has demonstrated weight loss of up to 20% or more in some patients, often exceeding results seen with GLP-1–only therapies.
  
• Liraglutide:
  SCALE trials indicate that daily liraglutide can lead to weight loss of 5–8% of initial body weight, especially when supported by dietary and physical activity changes.
  

Individual results vary, and maximum benefit is usually achieved with ongoing medical supervision and healthy lifestyle changes.

Side Effects, Tolerability, and Suitability

• Common Side Effects:
  All three medications may cause gastrointestinal symptoms such as nausea, vomiting, diarrhoea, constipation, and decreased appetite. These effects are usually temporary and can be minimised by gradual dose escalation.
  
• Tolerability:
  Some patients may tolerate one medication better than another. Weekly injections may be more convenient for those seeking fewer injections, while others may respond better to daily dosing.
  
• Contraindications:
  GLP-1 and dual agonist injections are not recommended for those with a history of medullary thyroid carcinoma, multiple endocrine neoplasia syndrome type 2, or certain gastrointestinal disorders. Your doctor will assess your full medical history before prescribing any of these medications.

GLP-1 & Dual Agonist Weight Loss Injection Comparison Table

* Average weight loss reflects clinical trial results with lifestyle intervention. Individual results may vary.

Which GLP-1 or Dual Agonist Injection Pen Is Best for You?

The choice between semaglutide, tirzepatide, and liraglutide depends on individual medical history, body mass index (BMI), treatment goals, preferences, and potential for side effects. 

A comprehensive assessment by your doctor is essential to determine the most appropriate option for safe and effective weight management.

Choosing the Best Clinic for Weight Loss Injection Therapy in Singapore

Selecting a reputable and experienced clinic is essential when starting prescription weight loss injection therapy with GLP-1 or dual agonist medications such as semaglutide, tirzepatide, or liraglutide. 

Proper medical supervision helps ensure your safety, treatment effectiveness, and ongoing support throughout your weight loss journey.

What to Look For in a Weight Loss Clinic

• Doctor-Led Care: Choose a clinic where consultations and prescriptions are provided by qualified doctors with experience in obesity management and metabolic health.
  
• Individualised Assessment: The best clinics conduct comprehensive medical assessments, review your history, and tailor treatment plans to your unique needs.
  
• Access to All Approved Options: A reputable clinic should offer a full range of prescription weight loss injection pens, including once-weekly and daily regimens.
  
• Ongoing Monitoring: Regular follow-up visits and clear communication are essential for dose adjustment, side effect management, and long-term results.
  
• Transparent Information: Look for clinics that provide clear explanations about treatment, expected outcomes, costs, and any possible risks.
  

Booking a Consultation for GLP-1 or Dual Agonist Injections

To begin treatment with prescription weight loss injection pens in Singapore, schedule a consultation with a licensed medical aesthetic clinic. 

During your visit, the doctor will perform a medical evaluation, discuss your goals, and recommend the most suitable option—such as semaglutide, tirzepatide, or liraglutide injections.

For more information or to book an appointment, please contact our clinic.

Frequently Asked Questions About Prescription Weight Loss Injection Pens in Singapore