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Guide

How GLP-1 medications work

Ozempic, Wegovy, Mounjaro and Saxenda are grouped together because they all work on the same basic principle. Here's what that principle is, in plain language — no jargon, no dosing instructions.

The hormone they're mimicking

After you eat, your gut naturally releases a hormone called GLP-1 (glucagon-like peptide-1). It does three main things: it tells your pancreas to release insulin when blood sugar is high, it slows down how quickly food leaves your stomach, and it signals to your brain that you're full. GLP-1 medications are designed to mimic that hormone at higher, longer-lasting levels than your body produces on its own.

Why that matters for diabetes and weight

For type 2 diabetes, the insulin and blood-sugar effects are the main benefit — better blood sugar control with a lower risk of the sugar spikes and crashes that come with meals. For weight management, the appetite and fullness effects tend to matter more — many people find they feel satisfied on less food, which supports gradual, sustained weight loss when combined with dietary and lifestyle changes.

How the medications on this site differ

  • Ozempic and Wegovy (semaglutide) act on the GLP-1 receptor only, and are injected once a week. Ozempic is registered for diabetes; Wegovy for weight management, at a higher maximum dose.
  • Mounjaro (tirzepatide) acts on both the GLP-1 and GIP receptors — a second, related gut hormone — and is also a once-weekly injection.
  • Saxenda (liraglutide) acts on the GLP-1 receptor and is injected once a day rather than once a week — it's an earlier generation of the same idea.

You can compare current pricing for each on its own page: Ozempic, Wegovy, Mounjaro, Saxenda.

Common side effects

Because these medications slow digestion, the most commonly reported side effects are gastrointestinal — nausea, constipation, diarrhoea, and reduced appetite — particularly when starting treatment or increasing dose. These usually ease over time. Less common but more serious risks exist too, which is why these medications require a prescription and medical supervision.

We don't publish dosing guidance

Deciding which medication, dose, and titration schedule is right for you is a clinical decision that depends on your health history. This site compares prices and explains the basics — it doesn't replace a consultation with a registered healthcare provider.

Next: buying legally

All of the medications above require a valid prescription and should only be sourced through a registered pharmacy or licensed telehealth clinic. See our guide on buying GLP-1 medications legally in South Africa.