GLP-1 Medications Explained: What Mounjaro and Wegovy Actually Do

What Is a GLP-1 Medication?

GLP-1 receptor agonists are a class of medication originally developed to treat type 2 diabetes, now widely used for weight management. GLP-1 stands for glucagon-like peptide-1, a hormone your gut naturally releases after eating. This hormone plays a key role in regulating appetite, blood sugar, and how quickly food moves through your stomach.

Medications like Wegovy (semaglutide) mimic this natural hormone, while Mounjaro (tirzepatide) goes a step further by acting on two hormone receptors — GLP-1 and GIP — which is why it is often associated with more pronounced results.

How These Medications Work

• Reducing appetite: They act on receptors in the brain that regulate hunger, helping you feel fuller with smaller portions.
• Slowing digestion: Food leaves the stomach more slowly, extending the feeling of fullness after meals.
• Improving blood sugar control: They help the body respond more effectively to insulin, smoothing out blood sugar spikes.

Mounjaro vs Wegovy: What's the Difference?

Both medications are delivered as a once-weekly injection and share a similar mechanism, but they are not identical:

• Wegovy (semaglutide) targets the GLP-1 receptor only.
• Mounjaro (tirzepatide) targets both the GLP-1 and GIP receptors, a dual mechanism that clinical trials suggest can lead to greater average weight loss for some patients.

Neither medication is automatically 'better' for everyone — the right choice depends on your individual health profile, goals, and how your body responds, which is why a prescriber reviews your suitability before treatment begins.

What to Expect When Starting Treatment

Treatment typically starts at a low dose, which is gradually increased over several weeks. This slow approach helps the body adjust and reduces the likelihood of side effects. Common effects in the early weeks can include nausea, mild digestive changes, or reduced appetite — these often ease as your body adapts.

These medications are not a quick fix on their own. They work best as part of a wider approach that includes sensible dietary changes and regular activity, and are intended for use under medical supervision.

Who Can Take Them?

GLP-1 medications for weight management are generally considered for adults with a raised BMI, sometimes alongside weight-related health conditions. A clinical assessment is required to check for any contraindications, such as certain thyroid conditions or a personal or family history of specific endocrine disorders.

Speaking to a Healthcare Professional

If you're considering treatment, an online consultation allows a UK-registered prescriber to review your medical history and confirm whether a GLP-1 medication is a safe and suitable option for you, before any prescription is issued.