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Semaglutide Shows Promise for Hard-to-Treat Obesity in Prader-Willi Syndrome — Up to 14.4% Weight Loss

evidence
The takeaway

Long-term semaglutide treatment in three Prader-Willi syndrome patients without diabetes showed variable but meaningful results, from preventing weight gain to achieving 14.4% weight loss, with good tolerability.

Up to 14.4% weight loss

achieved with semaglutide in a Prader-Willi syndrome patient — a condition where conventional weight management is nearly impossible due to brain-driven insatiable hunger

What the researchers found

Three PWS patients without diabetes received semaglutide (0.5-2 mg weekly) with long-term follow-up. Patient 1: weight maintenance with prevention of further gain. Patient 2: 14.4% weight loss from baseline. Patient 3: 11% weight loss from baseline. One patient had previously undergone metabolic surgery.

Semaglutide was well tolerated across all patients, including post-bariatric surgery. The variable response reflects the complex pathophysiology of PWS obesity, where dysfunction in satiety pathways, reward circuits, and hormonal regulation all contribute.

Why it matters

PWS affects about 1 in 15,000-25,000 births and is the most common genetic cause of severe obesity. Patients have insatiable hunger driven by brain dysfunction that makes conventional weight management nearly impossible. Finding that a GLP-1 drug can help — even in this extreme biological context — suggests semaglutide may work through mechanisms beyond simple appetite suppression.

How the study worked

Case series with long-term follow-up of three PWS patients treated with semaglutide at a single center. Treatment dosages ranged from 0.5 to 2 mg weekly. Clinical outcomes including weight change, tolerability, and safety were monitored. A literature review of GLP-1 RA use in PWS was also conducted.

What this study cannot tell us

This is a case series of only three patients — the smallest possible clinical evidence. There was no control group, and individual responses varied significantly. The optimal dose and duration of semaglutide for PWS are unknown. Long-term effects on the distinctive metabolic and hormonal abnormalities of PWS were not comprehensively assessed. The results cannot be generalized to all PWS patients.

How to read the evidence

This is a case series of three patients, representing the lowest level of clinical evidence. While the results are encouraging, randomized controlled trials are essential to establish efficacy and safety of semaglutide for PWS.

When this study was published

Published in 2024, this case series adds to the small but growing body of evidence on GLP-1 RA use in genetic obesity syndromes.

The bigger picture

GLP-1 drugs are primarily studied in common obesity and diabetes, but their potential in genetic obesity syndromes is largely unexplored. PWS represents perhaps the most challenging obesity phenotype, driven by fundamental brain circuitry dysfunction. If semaglutide can produce meaningful weight loss even in this context, it suggests the drug's central nervous system effects are more powerful than previously appreciated.

Questions still open

  • What predicts which PWS patients will respond well to semaglutide versus those who only maintain weight?
  • Would higher doses of semaglutide (up to 2.4 mg as used for obesity) produce better results in PWS?
  • Could combining semaglutide with other appetite-modifying therapies address PWS's complex obesity pathophysiology?

Common questions

What is Prader-Willi syndrome and why is it so hard to manage weight?
PWS is a genetic condition affecting about 1 in 15,000-25,000 people. It causes extreme, insatiable hunger driven by brain dysfunction in satiety and reward pathways, combined with low muscle mass and reduced metabolism. These factors make conventional dieting nearly impossible, and patients often develop severe obesity-related health problems.
Can semaglutide help with Prader-Willi syndrome obesity?
These three cases suggest it can help some patients — one lost 14.4% of body weight and another lost 11%, while a third maintained weight without further gain. Semaglutide was well tolerated. However, these are only three cases, and larger clinical trials are needed before it can be recommended as a standard treatment for PWS.

Read the original research

Case report: Long-term efficacy and safety of semaglutide in the treatment of syndromic obesity in Prader Willi syndrome - case series and literature review.

Frontiers in endocrinology, 15, 1528457

Citation

Koceva, Andrijana; Mlekuš Kozamernik, Katarina; Janež, Andrej; Herman, Rok; Ferjan, Simona; Jensterle, Mojca. (2024). Case report: Long-term efficacy and safety of semaglutide in the treatment of syndromic obesity in Prader Willi syndrome - case series and literature review.. Frontiers in endocrinology, 15, 1528457. https://doi.org/10.3389/fendo.2024.1528457