How Wegovy works

To truly understand how Wegovy works, it helps to first understand what it is and where it comes from.

Wegovy is a weight loss injection containing the active ingredient semaglutide. Semaglutide was originally designed to manage blood sugar levels in people with type 2 diabetes under the brand name Ozempic, but its effects on appetite and digestion quickly made it an effective obesity treatment. In January 2022, Wegovy was approved in the EU specifically for weight loss.

It comes in the form of a weekly injection pen, with doses ranging from 0.25 mg to 2.4 mg (a 7.2 mg dose is also available to some patients, although this is not a part of the typically prescribed dosage schedule).

Wegovy works by copying a hormone found naturally in the body called GLP-1, which is released after you eat. This hormone is responsible for:

While the natural version of this hormone only lasts for a few minutes, semaglutide lasts much longer. This makes the effects more sustained and consistent, causing you to eat less without all the hunger and cravings.

If you are more of a visual learner, I’ve included a diagram below explaining the science in more detail.

With Wegovy, you typically start with 0.25 mg once weekly, and up your dose every 4 weeks until you reach a maintenance dose of 2.4 mg. This is done to reduce the risk and severity of side effects.

If you’ve taken the 2.4 mg dose for at least 4 weeks and you’re tolerating it well, you can also talk to your doctor about moving up to 7.2 mg. A STEP UP trial suggests this dose is more effective than 2.4 mg, but it carries a higher risk of side effects, so speak with your doctor about it first.

Now that you understand how it works, let’s explore how long it can take before a noticeable change can be seen in your weight.

Wegovy starts working on your hormones as soon as you take it for the first time, and many of my patients tell me they notice a change in their appetite within days, even hours. However, weight loss is gradual, so it will take longer before you notice any weight loss.

Usually, you should see a change on the scale after a few weeks, as long as you are eating healthily and staying active.

Wegovy has been shown in clinical trials to be a highly effective weight loss treatment, with patients losing up to 21% of their starting weight in 15 months depending on the dosage.

In one study on Wegovy’s effectiveness, the average weight patients lost on the 2.4 mg dose was around 17% after 15 months. In a STEP UP trial, this number rose to around 21% for patients using the 7.2 mg dose.

Expert tips to maximise effectiveness

Wegovy isn’t a miracle drug, and it’s not going to make you lose weight without some effort on your part. The good news is, it’s far easier to make these changes on Wegovy.

Here are 5 key steps you can take to maximise weight loss potential with Wegovy:

1. Maintain a healthy, balanced diet: Wegovy makes you eat less, but it doesn’t make you eat healthily. Instead of restricting yourself completely from the foods you love, shift your focus to eating more healthy foods.
2. Stay active: The scale isn’t the only aspect of health you need to focus on when using Wegovy, and regular exercise is a great way to ensure you’re maintaining your overall health and fitness. A study exploring the link between walking and health found that 7,000 steps per day was linked to a 47% lower risk of all-cause mortality compared to 2,000 steps.
3. Incorporate strength training into your routine: Research on Wegovy’s relationship to muscles suggests that while it promotes fat loss, it may also lead to some muscle loss. That’s why I always recommend that my patients incorporate some strength training into their exercise routine if able.
4. Stay hydrated: Proper hydration is crucial for weight loss and overall health. Drinking plenty of water throughout the day helps with digestion, curbs cravings, and supports metabolism.
5. Sleep well: Never underestimate the power of a good night’s sleep. 7-9 hours of quality sleep every night can help regulate hormones, manage cravings, and improve your focus.

Because Wegovy works on digestion and appetite, the most common side effects are gastrointestinal. However, most of the time these side effects are mild and they usually go away once your body gets used to the medicine.

The most common side effects of Wegovy may affect more than 1 in 10 people. They include:

For a full list of possible side effects, see the patient information leaflet for Wegovy.

Tips for managing side effects

The most common side effects are gastrointestinal. If you're dealing with any gastrointestinal issues, try the following:

To learn more, check out my article on Wegovy side effects.

Also read: Wegovy vs Mounjaro: a doctor’s complete guide