What happens if you stop weight loss injections?

If you’ve ever lost weight, you’ll know how frustratingly easy it is to pile it all back on – and then some! This can happen even if you’ve been on GLP-1 receptor medications like semaglutide or tirzepatide, says DR BERNARD TAN, Medical Director at Bay Medical Clinic. So what happens if you stop weight loss injections? Dr Tan shares some insights, plus what you can do to manage your weight sustainably.

What GLP-1 receptor medications are

GLP-1 (short for glucagon-like peptide-1) is a naturally occurring hormone that helps regulate appetite and blood sugar, explains Dr Tan. Semaglutide is a GLP-1 receptor agonist that mimics the action of the hormone to regulate blood glucose, suppress appetite and slow gastric emptying.

Dr Tan dives a bit deeper into how it works. “The hormone GLP-1 is naturally secreted by the gut after a meal. GLP-1 medications bind to and activate the GLP-1 receptor in the brain, pancreas, gut, heart, liver, kidneys and blood vessels, triggering a wide range of beneficial metabolic effects.”

Meanwhile, tirzepatide is a dual GIP/GLP-1 receptor agonist that targets both GIP and GLP-1 receptors. Dr Tan elaborates: GIP, or gastric inhibitory polypeptide, is an incretin hormone the gut secretes in response to food intake. Similar to GLP-1, the GIP hormone acts to increase insulin production and suppress appetite.

Tirzepatide’s dual pathway, according to Dr Tan, makes the medication more potent than semaglutide, with studies showing tirzepatide to be more effective than semaglutide for the treatment of obesity.

“These medications have changed the landscape of obesity management and metabolic health,” says Dr Tan. “That’s especially true in the US, where semaglutide and tirzepatide are FDA-approved for the treatment of type 2 diabetes and obesity.”

What happens if you stop weight loss injections?

But before you rejoice and revert to your couch potato ways, you should know that medications like semaglutide and tirzepatide aren’t permanent fixes. In fact, people often experience a rebound in weight and appetite after they come off them. So what happens if you stop weight loss injections?

“Once weight loss injections are stopped, there is often gradual weight regain over the next 12 months,” says Dr Tan. “Studies show that on average, patients regain 50 to 60 percent of the weight they initially lost. Their diabetic control and cardiometabolic risk factors – like blood pressure and cholesterol – also tend to revert to their previous state.”

Dr Tan highlights the Surmount-4 clinical trial that looked at the issue of weight regain after treatment with tirzepatide. “After a 36-week treatment, patients were randomised into two arms – one where treatment was continued and a placebo arm where it was stopped. The former continued losing weight while the latter experienced steady weight regain,” shares Dr Tan.

Similarly, the Step-1 extension trial featuring 327 participants treated with semaglutide for 68 weeks produced similar results. “Within a year after stopping treatment, patients regained about two-thirds of the weight they lost. Their cardiometabolic risk factors such as blood sugar, blood pressure and high cholesterol also reverted to baseline.”

Dr Tan concludes, “Unfortunately, the positive effects of GLP-1 receptor medications don’t last forever. That’s why it’s common for patients to require a second course of medication two to three years after the initial treatment, after they have regained a significant amount of weight. In recent years, some patients are choosing long-term low-dose treatment, or ‘microdosing’, to help maintain their results.”

He notes that weight regain after GLP-1 medications is usually gradual compared to earlier classes of weight loss medication where the rebound could be dramatic.

Long-term solution with GLP-1 injections

Want to keep the weight off for good after using GLP-1 weight loss injections? “Lasting, sustainable weight loss comes from lifestyle changes,” advises Dr Tan. He highlights the importance of a well-rounded, multi-pronged approach that may involve:

• Lifestyle modifications: A balanced, nutrient-rich diet (think lean proteins, vegetables, whole grains) and regular exercise (like brisk walking or strength training) help set the foundation for keeping the weight off long-term
• Close monitoring of metabolic markers to detect early signs of relapse
• Restarting medication when clinically appropriate
• Long-term low-dose medication, aka “microdose”, is an area of active research, with studies showing potential benefits in weight management and metabolic health

“Personalised treatment plans and regular follow-up are key to preventing rebound weight gain,” he says.

Final thoughts

While GLP-1 weight loss injections like semaglutide and tirzepatide have given many a jumpstart on managing their health and weight, patients shouldn’t rely on them alone. Instead, Dr Tan says it should be part of a tailored plan for sustainable and healthy weight management. If you’re thinking about starting (or stopping) GLP-1 medication, have realistic expectations and speak to an experienced doctor.

Bay Medical Clinic is at #B2-12 Marina Bay Link Mall, 8A Marina Boulevard.
8428 7811 | bayclinic.sg

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