Eli Lilly stands at a familiar crossroads in the long history of corporate success: the moment when a single brilliant product begins to define, and thereby constrain, an entire enterprise. In the second quarter of 2026, the company's GLP-1 weight-loss drugs accounted for nearly two-thirds of its $23 billion in quarterly revenue—a concentration that speaks equally to extraordinary execution and to the quiet accumulation of structural risk. Growth rates are already moderating, competitors are circling, and the company is now racing to convert today's windfall into tomorrow's diversification. Wh