What to know before starting GLP-1 injections for weight loss

A practical guide for anyone considering this class of prescription weight-loss medications.

Not a permanent solution

Medications like semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro) are changing the health landscape in South Africa. Originally developed to manage type-2 diabetes, they’re now widely prescribed for weight loss. If your doctor has suggested one of these GLP-1 agonists, or you're simply curious, it helps to understand a few important considerations before starting treatment.

What are GLP-1 agonists?

GLP-1 stands for glucagon-like peptide-1, a hormone your body naturally produces after eating. “It tells your pancreas to release insulin, which slows digestion and communicates to your brain that you're full,” explains Dr Emmanuel Taban, a physician at Mediclinic Midstream. GLP-1 receptor agonists, like Ozempic, mimic this hormone, helping to regulate blood sugar and curb your appetite, which leads to significant weight loss. Your doctor may tell you to inject them daily or weekly.

Long-term considerations

“An important thing for people to understand about GLP-1 agonists is that they’re not a permanent fix on their own,” says Dr Taban. “Research shows that when people stop taking these medications, they regain a significant amount of weight, sometimes most of it. This means many patients need to stay on the treatment for years, which raises questions about cost, access, and sustainability.”

Muscle loss is another concern. "Losing weight too quickly can create complications, including gaps in essential nutrients, changes in body composition, and disruption of your metabolism," says Dr Taban. Most importantly, it can also cause you to lose muscle mass. "When you drop weight, you inevitably lose both fat and muscle,” he explains. “The quicker the weight loss, the greater the muscle loss. This is when problems such as muscle weakness and fatigue happen.”

This effect has also been linked to what’s become known as “Ozempic face” – a term widely used in the media to describe drastic facial changes in some celebrities and others who’ve lost weight rapidly. In many cases these changes in appearance are caused by the loss of both fat and muscle mass in the face while using GLP-1 medications.

Ways to compensate for muscle loss:

• Do resistance training. Strength training, such as squats, lunges, and exercises using resistance bands. All these help stimulate muscle growth.
• Prioritise protein. Include lean meats, fish, eggs, legumes and nuts in your diet to support muscle repair and growth.
• Balance your nutrition. Because you’ll have a reduced appetite, make sure to eat high-quality foods rich in vitamins, minerals, healthy fats, and protein.
• Stay hydrated. Muscle loss can contribute to dehydration, leading to fatigue and cramps. Aim to drink at least a few glasses of water a day.

Common side effects

Expect to feel slightly nauseous, especially in the first weeks as your body adjusts to the medication. Other digestive complaints may include:

• Vomiting
• Diarrhoea or constipation
• Bloating and stomach discomfort
• Acid reflux.

These symptoms often become more noticeable as your dose increases, which is why your doctor will gradually increase it.

The bottom line

GLP-1 agonists can be life-changing, but they shouldn’t be taken without proper medical support. “Always work closely with a qualified healthcare professional, discuss your full medical history, and think of these medicines as part of a holistic, sustainable approach to your health,” says Dr Taban.

The South African Health Products Regulatory Authority (SAHPRA) warns against the dangers of unverified GLP-1 products sold online or via informal channels. Authentic products will be sold under registered brand names – like Ozempic, Wegovy, or Mounjaro – in their original packaging.

It’s also important to know that because these medications are still relatively new, long-term data is limited. “Ongoing studies will continue to help us understand their full benefits and risks,” Dr Taban says.