How does Wegovy work for weight loss?

What is Wegovy?

Wegovy is a once-weekly injectable prescription medicine that contains semaglutide. It is designed to help adults who are overweight or obese lose weight as part of a programme that includes healthy eating and regular exercise.

Wegovy was approved by Medsafe for use in New Zealand in March 2025.

Is Wegovy Right for Me?

Wegovy may help with weight loss and weight management for adults who meet the following criteria:

• Have a BMI of 30 or more; or
• Have a BMI of 27 or more and at least one weight-related health condition, such as type 2 diabetes, high blood pressure, asthma, PCOS, erectile dysfunction, or high cholesterol.

Who Cannot Take Wegovy?

Wegovy is not suitable for everyone. You should not use Wegovy if you:

Please see the Medsafe Wegovy Consumer Medicine Information guide for further information: https://www.medsafe.govt.nz/consumers/cmi/w/wegovy.pdf

• Are a child (under 18)
• Are pregnant, trying to get pregnant, or breastfeeding
• Have type 1 diabetes
• Have a history of pancreatitis
• Have a personal or family history of medullary thyroid cancer or MEN2 syndrome
• Are allergic to semaglutide or any of the ingredients in Wegovy

How Does Wegovy Work?

Your body naturally produces a hormone called glucagon-like peptide-1 (GLP-1). GLP-1 helps control your appetite, how much you eat, and how your body handles sugar from food. Wegovy contains the active ingredient semaglutide, which works in a similar way to GLP-1. It sends signals to your brain and gut that help reduce feelings of hunger and slow how quickly food leaves your stomach.

Three ways Wegovy may help you lose weight:

1. Reduces appetite:

Wegovy acts like your natural GLP-1 hormone to help reduce hunger and food cravings between meals.

2. Slows digestion:

Wegovy slows how quickly food moves through your stomach, helping you feel fuller for longer and making it easier to be satisfied with smaller portions.

3. Supports blood sugar control:

By helping your body handle sugar from food more steadily, Wegovy may reduce the sharp ups and downs in blood sugar that can leave some people feeling tired and hungry soon after eating.

Overall, Wegovy can help you feel satisfied with less food, which for many people leads to gradual weight loss when paired with a lifestyle of healthy eating and regular exercise.

What Results to Expect with Wegovy

As people progress through their treatment programme, they may start to notice gradual weight loss, higher energy levels, and better mobility. In clinical studies, participants taking the highest dose of semaglutide (2.4 mg) lost, on average, around 15–17% of their body weight after using Wegovy for 68 weeks. ²

In addition to weight loss, many people in these studies also had improvements in blood pressure, cholesterol levels, and sleep quality.

Results vary from person to person. Some people see changes sooner, while for others it takes longer. Not everyone will have the same amount of weight loss, but many people using Wegovy, alongside healthy eating and physical activity, do experience some weight loss and health improvements.

Side Effects

Like all medicines, Wegovy can cause side effects in some people. The most common are nausea, vomiting, constipation, diarrhoea, stomach pain, and feeling tired. These are usually mild to moderate, tend to be temporary, and most often happen when you first start treatment or when your dose is increased. Some people do not experience any side effects at all.

Always talk to your healthcare provider if you have any concerns or questions about side effects.

For more detailed information on possible side effects, see our comprehensive guide.

Is Wegovy Good for Heart Health?

Wegovy may be a helpful option for some adults who want to lose weight and reduce their risk of certain heart-related problems.

In a large clinical trial (SELECT), researchers found that semaglutide (Wegovy) reduced the risk of serious heart problems, such as heart attacks and strokes, in people who were overweight or obese and already had heart disease.

Wegovy is now approved to lower the risk of heart-related events in adults who have established heart disease, do not have diabetes¹, and have a BMI of at least 27 kg/m².

How to Take Wegovy

Wegovy is taken once a week by injection under the skin (subcutaneous injection). You usually start on a low dose, which is slowly increased over time to help your body get used to the medicine.

A typical dosing programme might look like this:

Wegovy comes in pre-filled pens that each contain enough medicine for four once-weekly doses at each step. Injections are given into the upper arm, thigh, or abdomen. Because you need to see the window on the pen while injecting, it can be helpful to have someone else apply dosages to the upper arm. Do not inject Wegovy into a vein or muscle.

Remember, no two weight-loss journeys are the same. Your healthcare provider may adjust your dose or how quickly you increase it to suit your personal situation.

• Weeks 1–4: 0.25 mg once weekly
• Weeks 5–8: 0.5 mg once weekly
• Weeks 9–12: 1 mg once weekly
• Weeks 13–16: 1.7 mg once weekly
• Week 17 onwards: 2.4 mg once weekly (maintenance dose)

Will I Need to Pay for Wegovy?

Currently, Wegovy is not publicly funded in New Zealand, so you will need to pay the full cost yourself. You may also need to pay for any consultations with your healthcare provider related to starting and monitoring your treatment.

Do I Still Need to Maintain a Healthy Diet and Exercise?

Wegovy works best as part of a healthy lifestyle that includes balanced eating and regular exercise. Like any weight-loss medicine, it's not designed to be a stand-alone solution for long-term weight management.

Health New Zealand | Te Whatu Ora guidelines recommend a diet high in whole foods such as lean protein, fresh fruit and vegetables, a low intake of refined sugar and salt, and at least 2.5 hours of moderate exercise per week as the foundation for a healthy lifestyle.³ Using Wegovy alongside these healthy habits is often the recommended path to achieving and maintaining your weight-loss goals.

Talk to your healthcare provider for personalised advice on building a sustainable, healthy lifestyle.

Wegovy® is used for weight loss and weight maintenance in addition to diet and physical activity in adults and adolescents aged 18 years and above who meet certain Body Mass Index (BMI) criteria. Wegovy® is also indicated to reduce the risk of a heart disease–related event in addition to standard of care if you are an adult with a history of heart disease and have a BMI ≥27 kg/m² without established diabetes. Wegovy® contains the active ingredient semaglutide and is available in the following dose forms: 0.25 mg, 0.5 mg, 1.0 mg, 1.7 mg and 2.4 mg. The two lower-dose pens contain 1.5 mL of liquid each, while the three higher-dose pens contain 3 mL each. Wegovy® has risks and benefits. Ask your healthcare provider if Wegovy® is right for you. Use strictly as directed. If you experience side effects, see your doctor, pharmacist, or healthcare professional. Side effects of Wegovy® include nausea, vomiting, diarrhoea, constipation, abdominal pain, headache, and fatigue. Please refer to the Wegovy® Consumer Medicine Information available at: https://www.medsafe.govt.nz/consumers/cmi/w/wegovy.pdf

Footnotes

1. Wegovy’s cardiovascular indication is based on the SELECT trial, a large, randomised trial of semaglutide 2.4 mg once weekly in adults with overweight or obesity and established cardiovascular disease who did not have diabetes. Because the trial excluded people with diabetes, the label for this specific heart-disease indication also specifies “do not have diabetes.” This reflects the study design, not a universal rule that semaglutide cannot be used in people with diabetes.

2. In addition to a reduced-energy diet and increased physical activity. Based on results from two global studies involving 1,961 adults and 902 adults, respectively. This result was not the primary goal of the studies and should be considered as additional information. Mean weight loss of 15–17% (P<0.001 vs placebo) when taken over 68 weeks.

3. Ministry of Health. *Eating and Activity Guidelines for New Zealand Adults: Updated 2020*. Wellington, New Zealand: Ministry of Health; 2020. Available at: https://www.health.govt.nz.

Important safety information

Prescription medicine.