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This Study Changes the GLP-1 Deficiency Debate

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On The Pen GLP-1 News
Jul 18, 2026
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This may be one of the most important obesity papers published all year. Not because it introduces a new drug, but because it challenges one of the biggest assumptions in obesity medicine. For years, many experts have pushed back on the idea that people with obesity could be “GLP-1 deficient.” This new research suggests they may have been asking the wrong question. One of the biggest themes we’ve explored together recently is that obesity isn’t one disease. It’s a family of diseases, each driven by different biology. If that’s true, different patients shouldn’t just respond differently to treatment. They should need different treatments.

For years, this debate has quietly simmered in obesity medicine. Patients often describe GLP-1 medications as “replacing something their body was missing.” Many physicians, however, have pushed back on that language. Their argument has generally been that GLP-1 isn’t like insulin in type 1 diabetes. People with obesity don’t simply have a GLP-1 deficiency. The issue is believed to be far more complicated than that. Until now, they had a point. We didn’t really have convincing evidence that a distinct group of patients actually produced less GLP-1. That may have just changed.

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