If you’re prescribed Mounjaro or Wegovy you’ll need to inject the medicine just under the skin. Mounjaro and Wegovy should be injected once a week, on the same day and at around the same time.  Best injection sites are your tummy area (abdomen), the front of your thighs or your upper arm. Mounjaro and Wegovy need to be stored in the fridge before first use. Once you start using the Mounjaro pen, you can keep it for 30 days (or 6 weeks for Wegovy) either at room temperature (2 to 30°C) or in a fridge (2°C to 8°C). Do not freeze.

Orlistat and Xenical are capsule medicines. You take a single capsule with water, immediately before or up to one hour after a main meal. You can take your prescribed treatment up to three times a day. If you miss a meal, or have a meal that does not contain fat, you should not take Orlistat or Xenical at that time.

Common side effects of these medicines are nausea, vomiting, diarrhoea and constipation, heartburn and headache. There can also be an increased risk of gallstones. Uncommonly, there is a risk of pancreatitis, and rarely, allergic reactions. 

There are also some common side effects with Orlistat or Xenical that are caused by the extra fat being passed out through your stool. These include abdominal pain, oily diarrhoea, the urgent need to use the toilet, wind, and anal leakage. When used with the recommended low fat approach to your meals, these side effects can be reduced. There can also be headaches and increased anxiety.

For the full information on a medicine’s side effects and how to take it, it’s important to read the Patient Information Leaflet that comes with your medicine.

Both Orlistat and Xenical treatments start to work the first time you take a tablet with a meal. It will block some of the fat from being absorbed by the body.

Mounjaro and Wegovy start working straight away, and you could see or feel the effects within 2 to 4 weeks.

If you take your treatment as recommended with a healthy food plan, you can expect to lose at least 5% of your body weight over three to six months. It’s important to remember that although these medicines can help, changing your lifestyle and eating habits is what will sustain a healthy weight long term.