GLP-1 Medicines

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

Key Facts

• In Singapore, about 1 in 11 adults aged 18–74 lives with diabetes (around 9%), and obesity has risen to 12.7% - its highest recorded level (MOH National Population Health Survey 2024).
• In clinical trials, semaglutide (Ozempic / Wegovy) produced an average body-weight reduction of about 15% over 68 weeks (STEP 1 trial).
• The dual-acting tirzepatide (Mounjaro) produced about 20% average body-weight reduction versus about 14% for semaglutide in a 72-week head-to-head trial (SURMOUNT-5).
• These figures are trial averages - individual results vary and depend on continued treatment and lifestyle measures.

Overview

GLP-1 receptor agonists are a group of medicines that have become widely known for their role in type 2 diabetes and weight management. You may recognise them by their brand names - Ozempic and Wegovy (both semaglutide), Saxenda (liraglutide), and Mounjaro (tirzepatide, which works on GLP-1 and GIP). They mimic glucagon-like peptide-1, a gut hormone released after eating that helps the body regulate blood sugar and signals fullness. In Singapore these are prescription-only medicines, which means they are supplied only after a doctor has assessed you and decided that treatment is appropriate.

Interest in this group of medicines has grown quickly, and much of the public conversation has focused on weight loss. It is worth remembering that they were first studied and used in diabetes care, and that they are part of a broader treatment plan rather than a standalone solution. This article gives a plain-English overview of how they work, who they may suit, and what to consider. It is general information and not a substitute for a consultation with your own doctor.

What's the difference between Ozempic, Wegovy, Mounjaro and semaglutide?

A common point of confusion - these are often the same drug under different names:

• Semaglutide is the active ingredient in both Ozempic and Wegovy
• Ozempic is registered for type 2 diabetes
• Wegovy is the version dosed for weight management
• Mounjaro (tirzepatide) is a newer dual-acting medicine
• Saxenda (liraglutide) is an earlier GLP-1 medicine

Because two products can contain the same active ingredient but be registered, dosed and packaged differently, it can be easy to assume they are interchangeable. They are not. The strength, the titration schedule and the approved use can differ, and using a product outside the way it has been registered and prescribed may carry avoidable risk. Your doctor will advise which, if any, is appropriate for your situation.

Why it's used

• To improve blood glucose control in type 2 diabetes
• To support weight management in adults who meet clinical criteria
• As part of a wider plan that includes diet, physical activity and other treatment

In diabetes care, these medicines are often considered alongside, or after, other treatments depending on your blood glucose readings, your other health conditions and how you respond. In weight management, they are used in adults who meet defined clinical thresholds, usually relating to body mass index (BMI) and the presence of weight-related health conditions. In both situations the aim is to support an overall plan, and the medicine works with - not instead of - changes to eating patterns and activity.

How GLP-1 medicines work

• Prompt insulin release when blood glucose is raised
• Lower glucagon, a hormone that raises blood sugar
• Slow stomach emptying, so you feel full for longer
• Act on appetite centres in the brain to reduce hunger

GLP-1 is a hormone your gut releases naturally after a meal. These medicines mimic its action, which is why they affect both blood sugar and appetite. Because they prompt insulin release mainly when blood glucose is raised, the risk of low blood sugar from the medicine on its own is generally lower than with some other diabetes treatments - though this can change if they are combined with medicines such as insulin or sulfonylureas. The slowing of stomach emptying is also part of why some people notice digestive side effects, particularly when starting or increasing the dose.

Who may be suitable

Suitability is assessed individually. A doctor will consider your medical history, BMI, blood glucose, other medicines and goals before prescribing. They will also ask about your past and current health conditions, any history of pancreatitis or gallbladder disease, thyroid conditions, and whether you are pregnant, planning pregnancy or breastfeeding, as these medicines are generally not used during pregnancy. The decision is not based on weight or blood sugar alone - it is a clinical judgement that weighs the possible benefits against the risks for you as an individual.

Risks and side effects

• Common: nausea, vomiting, diarrhoea, constipation, reduced appetite - often as the dose increases
• Less common: gallbladder problems, pancreatitis
• Not suitable for people with a personal or family history of medullary thyroid carcinoma or MEN2 syndrome
• Always tell your doctor about other medicines and medical conditions

Most digestive side effects are mild to moderate and tend to ease as the body adjusts, which is one reason the dose is increased gradually. Eating smaller portions, avoiding very fatty or rich meals, and staying hydrated may help. Some symptoms, however, need prompt medical attention. Severe or persistent abdominal pain, ongoing vomiting, signs of dehydration, or symptoms of a gallbladder problem such as pain in the upper right abdomen should be discussed with a doctor without delay. If you experience these, contact your doctor or seek medical care rather than simply continuing.

Before you start

A consultation is needed to confirm eligibility, screen for contraindications, and plan monitoring. Important: GLP-1 medicines should never be self-sourced online or shared - counterfeit and improperly handled products are a real risk.

Products bought outside a registered supply chain may be fake, incorrectly dosed, or stored at the wrong temperature, and you cannot be sure what they contain. In Singapore, prescription medicines should be obtained through a properly licensed channel after a medical assessment.

Sharing a prescription with family or friends is also unsafe, because a medicine that is appropriate for one person may be harmful for another. The screening before treatment exists for good reason, and skipping it removes an important safeguard.

What to expect

The dose is usually started low and increased step by step to reduce side effects. Follow-up reviews track your response, tolerance and progress.

At an initial consultation, your doctor will take a history, may arrange relevant tests, and will discuss the potential benefits and risks so that you can make an informed decision. If you start treatment, you will usually be shown how to use the injection device and given guidance on storage and on what to do if a dose is missed. Follow-up appointments are used to check how you are tolerating the medicine, review any side effects, monitor relevant measurements and decide together whether to continue, adjust or stop. These reviews are an ongoing part of treatment rather than a one-off step.

Results

Effects on blood glucose and weight vary between medicines and individuals. Any specific figures should be based on published trial averages and explained by your doctor - results are not guaranteed and depend on continued lifestyle measures. Clinical trials have studied these medicines in both diabetes and weight management, and responses differ from person to person depending on the medicine used, the dose reached, other health conditions and how consistently lifestyle measures are maintained. Some people respond well, while others see a more modest effect or do not tolerate the medicine; your doctor can help you understand what is realistic for your circumstances.

Lifestyle and GLP-1 medicines

These medicines are intended to support, not replace, healthy habits. Eating patterns, physical activity, sleep and stress all play a part in blood sugar control and weight, and the benefit of treatment is more likely to be sustained when it sits within a broader plan. Because appetite is often reduced during treatment, it can help to focus on adequate protein and a balanced intake so that nutrition is maintained rather than simply eating less of everything. In the Singapore context, where dining out and shared meals are common, your doctor or a dietitian can offer practical guidance on portion sizes and food choices that fit your routine. Building habits that you can keep up over time tends to matter more than short-term changes.

What to discuss with your doctor

Before and during treatment, it helps to raise:

• All other medicines and supplements you take, including over-the-counter products
• Any history of pancreatitis, gallbladder disease, thyroid conditions or diabetic eye disease
• Whether you are pregnant, planning pregnancy or breastfeeding
• How any existing conditions are managed, so doses of other medicines can be adjusted if needed
• Your goals and any concerns about side effects, cost or how long treatment may continue

Being open about your full health picture allows the plan to be tailored to you and helps avoid interactions or complications.

Frequently Asked Questions

Is Ozempic available in Singapore?

GLP-1 medicines are prescription-only; availability is confirmed by your doctor and follows HSA registration.

Can I take Ozempic or Wegovy just for weight loss?

Some GLP-1 medicines are approved for weight management in eligible adults - a doctor assesses whether you qualify.

How are these medicines taken?

Most are given as a once-weekly or daily injection, depending on the specific medicine. Your doctor or nurse will show you how.

Do I keep the weight off after stopping?

Weight and glucose changes may reverse if treatment stops, which is why ongoing review and lifestyle measures matter.

Will I have low blood sugar on these medicines?

Used on their own, GLP-1 medicines carry a relatively low risk of causing low blood sugar, because they act mainly when glucose is raised. The risk can increase if they are combined with insulin or certain other diabetes medicines, which your doctor will take into account.

What happens if I miss a dose?

Guidance depends on the specific medicine and how it is dosed. Your doctor or pharmacist will explain what to do, and you should not double up doses to make up for a missed one without advice.

Can I drink alcohol while taking them?

Alcohol can affect blood sugar and may add to digestive side effects. It is worth discussing your usual intake with your doctor, who can advise based on your overall health.

How long will I need to take the medicine?

This varies. Some people use these medicines over the longer term as part of managing an ongoing condition, and your doctor will review with you whether to continue, adjust or stop at each follow-up.

Related reading: Ozempic; Wegovy; Mounjaro

Medical Resources & References

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