Weight-loss medications such as Wegovy and Mounjaro work on the biological signals that regulate hunger and fullness. They can support meaningful weight loss, but they are prescription treatments that need individual assessment, gradual dose adjustment and ongoing monitoring.
Southern Weight Loss provides specialist medical weight management for people across Otago, Southland and the lower South Island. Treatment is supported by a Bariatric Surgeon and NZ Registered Dietitian, with a plan that looks beyond the prescription itself.
No GP referral is needed. Book directly and we’ll take it from there.
What are weight-loss medications?
Weight-loss medications are prescription treatments that act on the systems controlling appetite, fullness and food intake. Medicines such as Wegovy and Mounjaro mimic naturally occurring gut hormones and can make hunger easier to manage.
They are not stimulants and they do not simply speed up metabolism. They work mainly by helping people feel less hungry, feel satisfied sooner and experience fewer persistent thoughts about food.
Medication works best as part of a wider plan that includes appropriate nutrition, muscle preservation, monitoring and a realistic long-term strategy.
Which weight-loss medications are available in New Zealand?
The appropriate medicine depends on medical history, current medications, previous treatment, side effects, treatment goals, availability and cost.
Wegovy, semaglutide
Wegovy is a once-weekly GLP-1 receptor agonist approved in New Zealand for weight management. It acts on appetite pathways in the brain, helping reduce hunger and increase fullness.
Treatment begins at a low dose and is increased gradually. This helps the body adjust and can reduce gastrointestinal side effects.
Mounjaro, tirzepatide
Mounjaro is a once-weekly GIP and GLP-1 receptor agonist approved in New Zealand for weight management in adults. It affects appetite, food intake and glucose regulation.
As with Wegovy, treatment starts at a low dose and is increased gradually according to response and tolerability.
What about Ozempic?
Ozempic also contains semaglutide, but its New Zealand indication is for the treatment of Type 2 diabetes. Wegovy is the semaglutide product specifically approved for weight management.
The brand, dose and reason for treatment matter. Medication should be selected following an individual clinical assessment rather than by brand recognition alone.
Who may benefit from a weight-loss medication assessment?
A specialist assessment may be useful for adults who have experienced persistent hunger, repeated weight regain or limited results from lifestyle treatment alone.
It may also be helpful for people who:
- Are considering Wegovy or Mounjaro and want a medically supervised plan
- Have weight-related health concerns such as Type 2 diabetes, high blood pressure, sleep apnoea or joint pain
- Have stopped medication because of side effects
- Have reached a plateau while taking medication
- Are regaining weight after stopping treatment
- Want to protect muscle and nutrition during weight loss
- Have had previous bariatric surgery and are experiencing weight regain or persistent food noise
- Want to compare medication with bariatric surgery
- Need a realistic long-term or maintenance plan
Medication is not suitable for everyone. The decision depends on an individual clinical assessment.
What happens at a Southern Weight Loss assessment?
1. Medical review
We review your health, weight history, previous weight-loss treatments, current medications and any conditions that may affect treatment.
The assessment may cover:
- Hunger, fullness and eating patterns
- Previous experience with GLP-1 medication
- Type 2 diabetes and other weight-related health conditions
- Gastrointestinal symptoms
- Previous abdominal or bariatric surgery
- Current blood tests and medication
- Pregnancy plans where relevant
- Treatment goals and long-term affordability
2. Discussion of the options
We explain which treatments may be appropriate and discuss the likely benefits, limitations, side effects, costs and long-term requirements.
This may include medication, nutrition support, bariatric surgery or a combination of treatments over time.
3. An individual treatment plan
If medication is appropriate, the plan will cover:
- Which medicine is being recommended and why
- The starting dose and dose-escalation schedule
- What to do if side effects develop
- Protein, fluid and nutritional priorities
- Follow-up and monitoring
- How treatment response will be assessed
- What happens if the medicine is ineffective, poorly tolerated or no longer affordable
4. Ongoing review
Follow-up is used to review progress, side effects, appetite, nutrition, muscle preservation and any changes in weight-related health conditions.
The dose does not need to increase automatically at every opportunity. It should be guided by clinical response and tolerability.
Why does monitoring matter?
Weight-loss medication can reduce appetite substantially. That can be helpful, but eating much less also creates a risk of missing protein, fluid, vitamins and minerals.
Monitoring may include:
- Dose escalation and side effects
- Protein and overall nutritional intake
- Hydration
- Muscle preservation
- Blood tests where clinically indicated
- Blood pressure, glucose and changes to other medication
- Constipation, nausea, reflux or vomiting
- Plateaus and treatment response
- The ongoing cost of treatment
- A plan for maintenance or stopping
Proper monitoring helps distinguish between a medicine that needs more time, a dose that needs adjustment and a treatment that is not working well for that individual.
A prescription is not the whole plan.
Nutrition and muscle preservation
The aim is not simply to make someone eat as little as possible.
Rapid weight loss can include muscle as well as fat, particularly when protein intake is low and there is no resistance exercise. Significant appetite suppression can also make it difficult to meet basic nutritional needs.
Helen Gibbs, NZ Registered Dietitian, can help with:
- Practical protein targets
- Meal structure when appetite is low
- Managing nausea, constipation or food aversions
- Hydration
- Vitamin and mineral intake
- Preserving muscle during weight loss
- Planning for plateaus and maintenance
What side effects can occur?
The most common side effects are gastrointestinal and may include:
- Nausea
- Constipation
- Diarrhoea
- Vomiting
- Abdominal discomfort
- Reflux or indigestion
- Reduced appetite that makes eating or drinking difficult
Side effects are often most noticeable when treatment begins or the dose increases. Gradual dose escalation and individual review can improve tolerability, but some people need to remain at a lower dose or stop treatment.
Rare but important complications can occur. Patients receive advice about symptoms that require urgent medical review. This page provides general information and does not replace the consumer medicine information or individual medical advice.
How much weight might someone lose?
Results vary between people and between medicines. Dose, treatment duration, side effects, nutrition, activity, medical conditions and individual biological response can all affect the result.
Some people respond strongly. Others lose a modest amount of weight or do not respond sufficiently to justify the cost and side effects. A monitored plan should include agreed measures of response and a point at which treatment is reviewed.
No medicine can guarantee a particular amount of weight loss.
How long does treatment continue?
Obesity is a chronic condition, so weight-loss medication is usually considered a long-term treatment rather than a short course.
Appetite commonly increases and weight regain is common after medication is stopped. That is a biological response, not evidence that the person has failed.
Before starting, it is worth discussing:
- Whether long-term treatment is affordable
- What would prompt a dose change
- How success will be measured
- What happens during a plateau
- Whether a lower maintenance dose may be appropriate
- What the plan will be if treatment stops
Can medication be used after bariatric surgery?
Yes, weight-loss medication may be considered after bariatric surgery in selected patients.
Possible reasons include weight regain, incomplete weight loss, persistent hunger or the return of food noise. Before prescribing medication, it is important to assess eating patterns, nutrition, the original operation and whether a surgical or anatomical problem needs investigation.
Because Southern Weight Loss provides both medical and surgical treatment, the review can consider the whole picture rather than assuming every plateau needs a higher dose or another operation.
Medication or bariatric surgery: which is better?
Medication and surgery are different tools rather than direct substitutes.
Weight-loss medication
- Does not require an operation
- Can produce clinically meaningful weight loss
- Requires ongoing prescriptions and pharmacy costs
- May be limited by side effects or treatment response
- Commonly requires long-term use to maintain its effect
- Often results in weight regain when stopped
Bariatric surgery
- Requires an operation and a recovery period
- Usually produces greater average and more durable weight loss
- Has surgical risks and lifelong nutritional requirements
- Has a higher upfront cost
- Changes appetite, fullness and metabolic signalling without a weekly prescription
- Still requires long-term follow-up and healthy routines
The right choice depends on health, previous treatment, the amount of weight loss needed, reflux, Type 2 diabetes, long-term affordability and personal preference.
An assessment is an opportunity to understand both options. It is not a commitment to medication or surgery.
Who provides the care?
Mr Mark Grant, FRACS
Mark is a fellowship-trained Bariatric Surgeon with experience across medical weight management, primary bariatric surgery and revisional treatment. His Upper Gastrointestinal expertise is particularly relevant when reflux, previous surgery or gastrointestinal symptoms affect the treatment decision.
Helen Gibbs, NZ Registered Dietitian
Helen has specialist experience in weight management and Type 2 diabetes. She helps patients maintain adequate nutrition, protect muscle and build an eating plan that remains practical while appetite is changing.
How much does weight-loss medication cost in New Zealand?
Weight-loss medicines are usually self-funded in New Zealand. The monthly cost varies according to the medicine, dose, supply and dispensing pharmacy.
Medication costs are separate from consultation and follow-up fees. Contact Southern Weight Loss for current appointment fees and ask a pharmacy for the current medicine price at the prescribed dose.
Cost matters because treatment may need to continue long term. Affordability should be discussed before treatment begins, not after a successful first few months.
Appointments across the lower South Island
Southern Weight Loss provides specialist weight-management appointments in:
- Dunedin
- Wānaka
- Invercargill
- Oamaru
Ask the team which location or appointment format is most suitable when booking.
Frequently asked questions
Do I need a GP referral for weight-loss medication?
No. Private patients can book an assessment directly with Southern Weight Loss. GP and specialist referrals are also welcome.
Who is eligible for weight-loss medication?
Eligibility depends on body mass index, weight-related health conditions, medical history, previous treatment and the medicine being considered. A prescription is only provided after an individual assessment confirms that treatment is clinically appropriate.
What is the difference between Wegovy and Ozempic?
Both contain semaglutide, but they have different New Zealand indications and dosing. Wegovy is approved for weight management. Ozempic is approved for the treatment of Type 2 diabetes. The appropriate product depends on the clinical reason for prescribing.
What is the difference between Wegovy and Mounjaro?
Wegovy contains semaglutide and acts on GLP-1 receptors. Mounjaro contains tirzepatide and acts on both GIP and GLP-1 receptors. Both are once-weekly prescription medicines, but response, side effects, dosing and cost differ between individuals.
How quickly is the dose increased?
Both medicines usually begin at a low dose and increase gradually. Dose escalation should take account of appetite response and side effects. Some patients need longer at a particular dose, and the highest dose is not automatically the right dose for everyone.
How much weight can someone lose with medication?
Weight loss varies considerably. The medicine, dose, duration, side effects, nutrition, medical history and individual biological response all influence the result. Treatment should include agreed measures of response rather than a guaranteed target.
What are the common side effects?
Common side effects include nausea, constipation, diarrhoea, vomiting, abdominal discomfort and reflux. These are often more noticeable when treatment begins or the dose increases. Persistent or severe symptoms require clinical review.
How long do people stay on weight-loss medication?
Weight-loss medication is usually considered a long-term treatment. Hunger and weight regain commonly return after it is stopped. The duration depends on response, side effects, health, affordability and the agreed maintenance plan.
What happens if the medication is stopped?
Appetite commonly increases after treatment stops, and some or much of the lost weight may return. Planning for maintenance, nutrition and alternative treatment should begin before stopping rather than after regain has occurred.
Can weight-loss medication be used after bariatric surgery?
Yes, it may be considered for selected patients with weight regain, incomplete weight loss or persistent hunger after surgery. Assessment should also consider nutrition, eating patterns, the original operation and possible anatomical problems.
Is weight-loss medication better than bariatric surgery?
Neither is best for everyone. Medication avoids an operation but usually requires ongoing treatment. Bariatric surgery has operative risks and lifelong nutritional requirements, but generally produces greater and more durable average weight loss. Individual assessment is needed to compare them properly.
How much does weight-loss medication cost?
Weight-loss medication is generally self-funded in New Zealand. The cost varies by medicine, dose, supply and pharmacy. Consultation and monitoring fees are separate. Current costs should be confirmed before treatment begins.
Weight-loss medication guides
Explore our in-depth guides to weight-loss medication:
Start with a specialist assessment
Weight-loss medication is not the right treatment for everyone. An assessment can clarify whether medication, surgery or another approach is most appropriate.
No GP referral needed. Book directly and we’ll take it from there.
Call 03 464 0970
Important information
All treatments are prescribed following individual clinical assessment. Results vary between individuals. This information is general in nature and does not replace personalised medical advice or the approved consumer medicine information.