GLP-1 Side Effects: What to Expect and How to Manage Them
GLP-1 receptor agonists such as semaglutide (Ozempic, Wegovy) and liraglutide (Saxenda) have become some of the most effective medications for weight loss available in Malaysia. While clinical trials confirm their strong efficacy, understanding the potential side effects helps you prepare for treatment and know what is normal.
How GLP-1 Medications Cause Side Effects
GLP-1 receptor agonists work by mimicking a natural gut hormone that slows gastric emptying, reduces appetite, and helps regulate blood sugar. Most side effects stem from this mechanism -- particularly the slower movement of food through your digestive system. As your body adjusts to the medication over the first few weeks, these effects typically diminish.
Common Side Effects
The following side effects are experienced by a significant proportion of patients and are generally mild to moderate. They tend to appear during the dose-titration phase (when your dose is being gradually increased) and usually improve within the first few weeks.
Nausea
The most frequently reported side effect, affecting up to 40% of patients during dose titration. It often decreases significantly after 4 to 8 weeks. Eating smaller, more frequent meals and avoiding greasy foods can help.
Diarrhoea
Loose stools or increased bowel frequency are common early on. Staying hydrated and sticking to bland, easily digestible foods can ease symptoms.
Constipation
Slower gastric motility can also lead to constipation in some patients. Increasing fibre intake and drinking plenty of water helps manage this.
Reduced Appetite
While this is the intended therapeutic effect, some patients find the appetite reduction more pronounced than expected initially. It is important to still eat balanced meals to maintain nutrition.
Headache and Fatigue
Mild headaches and tiredness can occur as your body adjusts. Ensuring adequate hydration and sleep usually resolves these.
Injection Site Reactions
Minor redness, swelling, or itching at the injection site is normal. Rotating injection sites between the abdomen, thigh, and upper arm can minimise this.
Less Common but Serious Side Effects
While rare, some side effects require prompt medical attention. Contact your doctor or seek emergency care if you experience any of the following:
Pancreatitis
Severe, persistent abdominal pain that radiates to your back, possibly accompanied by vomiting. This is rare but requires immediate medical attention. Your doctor will monitor your symptoms and may order blood tests during treatment.
Gallbladder Problems
Rapid weight loss from any cause can increase the risk of gallstones. Symptoms include sudden pain in the upper right abdomen, nausea, and vomiting. Report these symptoms to your doctor promptly.
Hypoglycaemia
Low blood sugar is uncommon with GLP-1 medications alone but can occur if you are also taking insulin or sulfonylureas. Symptoms include shakiness, sweating, confusion, and rapid heartbeat.
Allergic Reactions
Very rarely, some patients may experience swelling of the face, lips, tongue, or throat, or difficulty breathing. Seek emergency medical care immediately.
Practical Tips to Manage Side Effects
Eat smaller, more frequent meals instead of large portions
Avoid high-fat, greasy, or spicy foods during the adjustment period
Stay well-hydrated -- aim for at least 2 litres of water daily
Follow the dose-titration schedule your doctor prescribes; do not skip ahead
Take your injection at a consistent time each week (for weekly medications)
Keep a food and symptom diary to identify triggers
Prioritise protein-rich foods to maintain muscle mass during weight loss
Get light exercise such as a 20-minute walk after meals to aid digestion
When to See a Doctor
While most side effects resolve on their own, you should contact your Seimbang doctor if you experience:
- Nausea or vomiting that persists beyond 2 weeks or prevents you from eating
- Severe abdominal pain, especially if it radiates to your back
- Signs of dehydration such as dark urine, dizziness, or fainting
- Symptoms of an allergic reaction (swelling, difficulty breathing, rash)
- Rapid heartbeat, confusion, or excessive sweating that could indicate low blood sugar
- Any symptoms that feel unusual or that concern you
At Seimbang, your prescribing doctor monitors your progress throughout treatment. You are never left to manage side effects alone -- regular check-ins are built into your programme so we can adjust your dosage or provide additional support whenever needed.
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Check Your EligibilityThe Bottom Line
GLP-1 medications are clinically proven to be safe and effective for weight loss when prescribed and monitored by a licensed physician. Most side effects are mild, temporary, and manageable with simple lifestyle adjustments. The key is gradual dose titration and open communication with your doctor. Understanding what to expect empowers you to stay on track with your weight loss goals.
Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a licensed healthcare professional before starting, stopping, or modifying any medication. Individual results and side effects may vary. If you experience severe or persistent symptoms, seek immediate medical attention.
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Get StartedDr. Sarwhin Sugumaran
Lead Physician at Seimbang. MD (USM), MMC-registered physician. Lead Physician at Seimbang and Klinik Care 360, Puchong.
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