Understanding Semaglutide and GLP-1 Receptor Agonists
In Singapore, effective diabetes management and weight loss are crucial health concerns for many individuals. While healthy lifestyle changes play a vital role in treatment, medications can significantly enhance control over blood sugar levels and aid in weight management.
Among these medications are GLP-1 receptor agonists (GLP-1 RAs), a class that includes Semaglutide, which is marketed under the brand names Rybelsus, Ozempic, and Wegovy. Another prominent drug in this class is Tirzepatide, marketed as Mounjaro for diabetes and Zepbound for weight loss.
What is Semaglutide?
Semaglutide is a GLP-1 RA that mimics the action of the incretin hormone, which is naturally produced in the intestines. This hormone helps regulate insulin secretion and reduces blood sugar levels after meals. Semaglutide, in its various forms—Rybelsus, Ozempic, and Wegovy—has been shown to provide dual benefits: controlling blood sugar and promoting weight loss.
How do GLP-1 RAs such as Semaglutide (Rybelsus, Ozempic, Wegovy) and Tirzepatide (Mounjaro, Zepbound) work?
GLP-1 receptor agonists like Semaglutide (including Rybelsus, Ozempic, Wegovy) and Tirzepatide (Mounjaro, Zepbound) act on the receptor for a hormone produced in the gut. They help control blood sugar and weight in several ways:
- Increases Insulin Secretion: Stimulates insulin release when blood sugar levels rise, particularly after meals.
- Reduces Glucagon Release: Lowers the amount of glucagon, which increases blood sugar, thus optimizing fasting blood sugar levels.
- Slows Gastric Emptying: Delays digestion, which helps reduce appetite and promotes feelings of fullness.
- Modulates Hunger Hormones: Influences the brain's reward center, reducing cravings.
Benefits of Semaglutide (Rybelsus/Ozempic/Wegovy), Tirzepatide (Mounjaro/Zepbound), and other GLP-1 RAs
Blood Sugar Control
Maintaining blood sugar levels is crucial to reduce the risk of complications from diabetes. Ozempic has demonstrated significant reductions in HbA1c levels, an indicator of average blood sugar over time, by up to 1.8% over 40 weeks in clinical trials.
Weight Loss
Wegovy and Tirzepatide have shown the potential for significant weight loss, with patients losing 15% to 20% of their body weight over 1.5 years. While Saxenda and Wegovy are specifically approved for weight loss, Rybelsus and Ozempic can lead to weight loss as a secondary effect.
Cardiovascular and Renal Benefits
Preliminary research indicates that Semaglutide may reduce the risk of cardiovascular events by more than 25% and improve kidney function in diabetic patients.
What is Rybelsus?
Rybelsus is a form of Semaglutide that’s approved for treating diabetes. It is taken daily in the form of a tablet rather than being injected weekly.
Rybelsus is generally taken at a dose of 3 mg per day for the first 30 days. This is then increased to 7 mg and subsequently 14mg per day. The tablet must be taken at least 30 minutes before the first meal of the day, allowing for optimal absorption.
What is Ozempic?
Ozempic is another form of Semaglutide approved for the treatment of type 2 diabetes. It’s taken by injection once per week. Ozempic comes in a pre-filled pen used for self-injection of the medication. Each pen may contain one or several doses.
Ozempic is usually started at a low dose of 0.25 mg per week. This is continued for four weeks to help the body adjust to the medication, which helps to reduce side effects. Afterward, the dose is increased to 0.5 mg per week. Some people continue at this dose, while others increase to 1 mg or 2 mg per week based on individual blood sugar control needs.
What is Wegovy?
Wegovy is another form of Semaglutide, specifically approved for weight loss. Similar to Ozempic, Wegovy is taken by injection once per week. It also comes in a pre-filled pen, each of which may contain one or several doses.
Wegovy is started at a low dose of 0.25 mg per week, increased every four weeks to 0.5 mg, 1 mg, and then 1.7 mg per week. Some people remain on a dose of 1.7 mg for the long term, while in others, the dose may be further increased to 2.4 mg per week.
What is Tirzepatide (Mounjaro and Zepbound)?
Tirzepatide is another GLP-1 RA that has gained attention for its potential benefits in diabetes management and weight loss. Marketed as Mounjaro for diabetes and Zepbound for weight loss, Tirzepatide can lead to weight loss of about 20%. Similar to semaglutide, it works by enhancing insulin secretion and reducing appetite, but it may also interact with different pathways in the body, potentially providing unique benefits for various conditions.
Which GLP-1 RAs are available in Singapore?
In Singapore, until recently, only liraglutide (Saxenda) was approved for weight loss. However, Wegovy, a form of Semaglutide, has been recently approved for weight loss treatment. For diabetes management, Rybelsus (oral tablet) and Ozempic (injection) are available. Of note, due to a global supply shortage, Ozempic and Wegovy are not widely available.
Tirzepatide (Mounjaro and Zepbound) are currently not available. Dulaglutide (Trulicity) and liraglutide (Victoza) are approved for diabetes treatment in Singapore. While all these medications have the potential to cause weight loss as a side effect, they are primarily intended for controlling blood sugar levels.
Different Forms of GLP-1 RAs
For patients who prefer injections, Ozempic and Wegovy are administered through once-weekly injections, while Rybelsus is the first oral GLP-1 RA. Tirzepatide (Mounjaro and Zepbound) is also injected weekly, providing an alternative to patients managing both diabetes and obesity.
How to Get the Most Benefit from Semaglutide (Rybelsus, Ozempic & Wegovy) and Tirzepatide (Mounjaro & Zepbound)
To maximize the effectiveness of GLP-1 RAs like Rybelsus, Ozempic, Wegovy, and Tirzepatide, it is essential to complement these medications with a balanced diet and regular physical activity. Such lifestyle changes not only support blood sugar control but also contribute to sustained weight loss.
Potential Side Effects of Semaglutide (Rybelsus/Ozempic/Wegovy), Tirzepatide (Mounjaro/Zepbound), and Other GLP-1 RAs
Common side effects may include:
- Nausea and vomiting
- Constipation or bloating
- Abdominal pain
- Headaches
- Indigestion
Most side effects are generally mild and may decrease over time. However, if severe reactions occur, such as allergic responses or significant gastrointestinal symptoms, patients should consult their doctors immediately.
Semaglutide (Rybelsus, Ozempic & Wegovy) FAQs
