Weight-Loss Injections Are Replacing Bariatric Surgery – Why and How?

In recent years, glucagon-like peptide-1 (GLP-1) analogues used to treat obesity, also called "incretin mimetics" and commonly known as "weight-loss injections", have proved highly effective for weight loss.

Could semaglutide (Ozempic), tirzepatide (Mounjaro) and similar medicines reduce the role of bariatric surgery or even eliminate it completely?

Weight-Loss Injections and Bariatric Surgery: Competitors?

GLP-1 analogues produce effective results in obesity treatment. But do they reduce the need for bariatric surgery? There are signs of this trend, particularly in the United States. However, it is too early to attribute it solely to the medicines' effectiveness. Given the risks of surgery, the trend is viewed as a positive development.

Prof. Dr. Matthias Blüher, head of the University of Leipzig Obesity Clinic and media spokesperson for the German Obesity Society, discussed this question and how medicines interact with surgery.

Dr. Blüher describes a different picture in Germany. High medicine costs and the lack of health insurance coverage lead many patients toward bariatric surgery. A decline in obesity surgery is therefore not expected in the near future, at least in Germany.

In Turkey, however, uptake of weight-loss injections may follow a pace closer to the United States than Germany.

Before exploring the details, let us examine injectable medicines used for weight loss that have been approved by the FDA (United States Food and Drug Administration):

A New Era: Surgery or Medicine?

Thanks to GLP-1 analogues, we can say that "a new era in medicine has begun". However, obesity treatment is more than a choice between surgery and medicine. Models combining both approaches may benefit a broader range of patients.

For example, the University of Leipzig recommends semaglutide before bariatric surgery. Preoperative weight loss plays an important role in reducing surgical risks. In addition, using GLP-1 analogues to prevent weight regain after surgery is possible.

Which Is More Effective: Medicines or Surgery?

GLP-1 analogues such as tirzepatide can produce an average weight loss of 23%, while sleeve gastrectomy or bypass surgery can raise this to 30-35%. However, medicines may produce results similar to less effective procedures such as gastric banding.

For people with very severe obesity, such as those with a body mass index (BMI) above 50, evidence on the effectiveness of weight-loss injections is insufficient, and surgery remains the most appropriate option. Surgery may also be more appropriate for patients awaiting a heart transplant because of severe heart failure or needing rapid weight loss for knee or hip replacement.

Durability: Does Surgery or Medicine Have the Advantage?

Weight loss achieved through bariatric surgery is known to be more durable in the long term. Sustaining results from GLP-1 analogues, by contrast, requires regular medication use and lifestyle changes. However, evidence on their long-term effects over 10-20 years remains insufficient.

For patients with a body mass index (BMI) below 35, diet and exercise should be the first treatment approach. If these are insufficient, medication may be considered next, with surgery reserved as a last resort. In particular, surgery is not an appropriate initial treatment for people carrying 10-20 kilograms of excess weight.

Conclusion: The Importance of an Integrated Approach

Although GLP-1 analogues represent a revolutionary advance in obesity treatment, they are not currently viewed as a complete replacement for bariatric surgery. They may, however, substantially reduce the need for surgery over time. Both approaches offer advantages to different patient groups, making individualized treatment plans increasingly important.

In the coming years, multifaceted strategies combining medicines and surgery are expected to offer hope to more patients with obesity. Healthcare systems must therefore expand access to these medicines and support research into their long-term effects.

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