GLP-1 Drugs for Weight Loss: How They Work and How to Choose the Right Medication
Article reviewed by Dr Harvey
Medical Director of Skinscape Clinic
GLP-1 receptor agonists have changed how we approach weight management. Body weight is influenced by more than lifestyle alone — hormonal and metabolic signals play a key role.
At Skinscape Clinic, GLP-1 receptor agonists are a part of a structured medical weight management approach, where treatment decisions are guided by metabolic health, lifestyle patterns, and long-term sustainability.
What Are GLP-1 Drugs?
GLP-1 is a natural hormone released by the gut after eating.
It sends signals to multiple organs in the body, including the brain, pancreas, and digestive system, to help regulate metabolism.
GLP-1 signalling helps the body to:
- reduce hunger signals
- increase feelings of fullness
- improve insulin response
- stabilise blood sugar levels
- slow stomach emptying
- influence how the body stores and uses energy
When metabolic signalling becomes disrupted (often due to insulin resistance, chronic inflammation, or prolonged metabolic stress) appetite regulation becomes less efficient. This can lead to increased hunger, cravings, and gradual weight gain.
GLP-1 medications help restore these signalling pathways, allowing appetite control and metabolic function to improve.
Because of these effects, GLP-1 medications have become an important medical tool in modern metabolic and weight management care, and they form part of the treatment options discussed during weight management consultations at Skinscape Clinic.
GLP-1 Drugs at Skinscape
Several medications within the GLP-1 family are currently used in clinical practice at Skinscape Clinic.
They differ in delivery method, strength of metabolic effect, and treatment goals.
Commonly prescribed medications include:
- oral semaglutide (Rybelsus) — taken as a daily tablet
- semaglutide injection (Ozempic) — administered as a weekly injection pen
- tirzepatide injection (Mounjaro) — a newer dual-hormone injection given weekly
Although these medications belong to the same therapeutic family, they differ in potency and metabolic impact.
Choosing between them requires medical assessment, as treatment suitability depends on a patient’s metabolic profile, weight history, and treatment goals.
These medications may be discussed during consultation at Skinscape Clinic when they are considered medically appropriate.
Oral GLP-1 Drugs: Oral Semaglutide (Rybelsus)
Oral semaglutide (Rybelsus) is currently the main oral GLP-1 medication available.
Unlike injectable treatments, it is taken as a daily tablet, which some patients prefer.
Because oral absorption is less efficient than injection delivery, its metabolic effect tends to be milder and more gradual.
At Skinscape Clinic, oral Rybelsus be considered when patients:
- prefer tablets rather than injections
- have mild insulin resistance or early metabolic dysfunction
- require moderate appetite regulation
- are aiming for gradual weight reduction
In clinical practice, oral GLP-1 therapy can sometimes serve as an early metabolic support option, particularly when the goal is improving metabolic balance (such as improving blood pressure, sugar and insulin regulation) rather than achieving rapid weight reduction.
Weight Loss Injections: Semaglutide (Ozempic)
Semaglutide injection (Ozempic) is a once-weekly GLP-1 injection pen.
Because the medication is delivered directly through injection, it is absorbed more efficiently and produces more consistent metabolic effects compared with oral therapy.
Patients using semaglutide injections may experience:
- reduced appetite
- fewer food cravings
- improved blood sugar control
- improved insulin sensitivity
- gradual weight reduction
For patients whose weight gain is driven by persistent hunger, cravings, or insulin resistance, injectable GLP-1 therapy may provide stronger metabolic support than oral medication alone.
Dual-Hormone Weight Loss Injections: Tirzepatide (Mounjaro)
Tirzepatide (Mounjaro) represents a newer development in metabolic medicine.
Unlike earlier GLP-1 medications that act on a single hormone pathway, tirzepatide activates two metabolic hormones:
- GLP-1
- GIP (glucose-dependent insulinotropic polypeptide)
These hormones both play roles in appetite regulation, insulin response, and energy metabolism.
By activating both pathways, tirzepatide can produce a broader metabolic effect, which may translate into stronger appetite regulation and greater overall weight reduction.
Clinical studies in the Surmount trials have demonstrated improvements in:
- appetite regulation
- insulin sensitivity
- fat metabolism
- metabolic markers linked to cardiovascular health
- blood pressure
Tirzepatide injection pen (Mounjaro) is also available at Skinscape Clinic, allowing patients who require deeper metabolic intervention to access a broader range of treatment options under medical supervision.
Strongest 
Tirzepatide (Mounjaro)
↓
Semaglutide injection (Ozempic)
↓
Oral semaglutide (Rybelsus)
Weakest
Effectiveness of GLP-1 Medications
Based on clinical research and clinical experience at Skinscape Clinic, the relative strength of metabolic effect generally follows the pattern on the right.
However, the most appropriate medication is not necessarily the strongest option.
At Skinscape Clinic, treatment recommendations are made after evaluating several factors, including:
- body weight and BMI
- blood tests for glucose levels, cholesterol, and other metabolic markers
- medical history
- cardiovascular risk factors
- lifestyle patterns, exercise frequency
- patient preferences
The aim is to design a personalised treatment plan that is medically appropriate and sustainable over time, rather than simply choosing the most potent medication.
GLP-1 Drugs Side Effects
Like all medications, GLP-1 drugs may cause side effects.
The most common side effects involve the digestive system and typically occur during the initial phase of treatment or when doses are increased.
Common GLP-1 drug side effects include:
- nausea
- reduced appetite
- bloating
- constipation
- diarrhoea
- mild stomach discomfort
These symptoms usually improve as the body gradually adjusts to the medication.
At Skinscape Clinic, treatment is introduced gradually through careful dose titration, allowing the body to adapt progressively. This approach helps minimise side effects while maintaining patient safety and comfort throughout treatment.
Because these medications affect metabolic pathways, proper medical assessment and monitoring are essential.
Weight Loss Injection Pens: How They Are Used
Many GLP-1 medications used for weight management are delivered using pre-filled injection pens.
These pens are designed for once-weekly self-administration, typically injected under the skin in the abdomen, thigh, or upper arm.
The needles are very small, and most patients find the injections painless and relatively easy to perform after proper instruction.
At Skinscape Clinic, patients receive clear guidance on:
- injection technique
- dosing schedules
- monitoring weight and metabolic markers
- recognising possible side effects
This ensures treatment can be carried out safely, confidently, and comfortably at home.
A Metabolic Approach to Weight Management
Weight management is not simply about reducing calorie intake or suppressing appetite. Metabolism, hormones, sleep, stress, muscle mass, and nutrition all influence how the body regulates weight.
For this reason, GLP-1 therapy is often combined with broader lifestyle strategies to support healthier metabolic function over time.
At Skinscape Clinic, weight management is approached through a structured programme that combines medical treatment, metabolic monitoring, and supportive therapies. Patients receive guidance on lifestyle factors that support metabolic health, alongside treatments including:
- ReduStim, which targets visceral fat metabolism through bio-electrical stimulation
- Clatuu fat freezing, which helps reduce stubborn localised fat deposits
- InBody scans, used to monitor body composition and track fat and muscle changes
- blood tests, used periodically to monitor metabolic markers
Together, these elements allow weight management to be approached more holistically, with attention to both weight reduction and long-term metabolic health.
Frequently Asked Questions About GLP-1 Weight Loss Medications
What are GLP-1 drugs for weight loss?
GLP-1 receptor agonists are medications that mimic a natural hormone involved in appetite and metabolic regulation.
They help reduce hunger signals, improve feelings of fullness, and support better blood sugar control.
Because of these effects, GLP-1 medications may be considered as one of the treatment options within a structured weight management program at Skinscape Clinic.
What GLP-1 drugs are available in Singapore?
GLP-1 medications available through prescription include:
- oral semaglutide (Rybelsus)
- semaglutide injection (Ozempic)
- tirzepatide injection (Mounjaro)
These medications differ in delivery method and metabolic potency, so treatment suitability depends on medical assessment. During consultation at Skinscape Clinic, the doctor evaluates a patient’s metabolic health and treatment goals before recommending an appropriate option.
Are there oral GLP-1 drugs?
Yes.
Oral semaglutide (Rybelsus) is a GLP-1 medication available as a daily tablet.
It generally produces a gentler metabolic effect compared with injectable GLP-1 medications and may be considered for patients who prefer oral treatment. At Skinscape Clinic, oral GLP-1 therapy may be discussed for patients whose metabolic profile and treatment goals are suitable for this approach.
What are the side effects of GLP-1 drugs?
Common side effects may include:
- nausea
- reduced appetite
- bloating
- constipation
- diarrhoea
These symptoms are usually mild and tend to improve as the body adapts to treatment.
For our patients, medications are introduced gradually through careful dose titration, allowing the body to adjust while helping minimise side effects. Patients are monitored during treatment so that dosing and response can be reviewed when necessary.
What are the side effects of weight loss injections?
Weight loss injections that act on GLP-1 pathways may cause digestive side effects, particularly during the early stages of treatment.
Examples include nausea, stomach discomfort, or reduced appetite.
Because these medications influence metabolic hormones, they should only be used under medical supervision. Patients undergoing treatment at our clinic are monitored so that any side effects can be managed appropriately during the course of therapy.
How do weight loss injection pens work?
Most GLP-1 medications used for weight management are delivered through pre-filled injection pens.
The medication is injected under the skin once weekly using a small needle.
During consultation and treatment, patients are guided on how to administer the injection safely, including injection technique, dosing schedules, and how to monitor their response to treatment.
Which is stronger: semaglutide or tirzepatide?
Tirzepatide activates both the GLP-1 and GIP hormone pathways, while semaglutide acts mainly on the GLP-1 pathway.
Because of this dual mechanism, tirzepatide has shown stronger weight reduction effects in clinical studies.
However, the most appropriate treatment depends on individual health status and treatment goals. At Skinscape Clinic, medication choice is determined after consultation, taking into account metabolic health, medical history, and long-term treatment sustainability.
Are GLP-1 drugs safe?
GLP-1 medications have been studied extensively for the treatment of diabetes and metabolic conditions.
When prescribed appropriately and monitored by a doctor, they are generally considered safe for suitable patients.
However, like all medications, they may cause side effects and are not suitable for everyone. A medical consultation is required to determine whether GLP-1 therapy is appropriate based on an individual’s health history and metabolic profile. At Skinscape Clinic, treatment recommendations are made only after a medical assessment to ensure that the therapy is suitable and safe for the patient.
How much weight can you lose with GLP-1 medications?
Weight loss results can vary from person to person and depend on several factors, including metabolic health, starting weight, lifestyle habits, and the specific medication used.
Clinical studies have shown that GLP-1–based treatments may support meaningful and gradual weight reduction over time when combined with appropriate lifestyle changes.
It is important to understand that these medications are not designed as a quick fix. They work by helping regulate appetite, improve metabolic signalling, and support healthier eating patterns.
At Skinscape Clinic, GLP-1 therapy is typically used within a structured weight management programme that includes lifestyle guidance, metabolic monitoring, and supportive treatments. The goal is not simply rapid weight loss, but sustainable improvements in metabolic health and body composition over time.
During consultation, the doctor will discuss realistic expectations and treatment goals based on an individual’s health profile.
