Eli Lilly

Eli Lilly achieved what bamboo demonstrates in tropical forests: explosive vertical growth that redefines the canopy. In Q3 2025, revenue surged 54% to $17.6 billion, driven entirely by tirzepatide—the dual GIP/GLP-1 agonist sold as Mounjaro for diabetes and Zepbound for obesity. Together they generated $10.1 billion in a single quarter, dethroning Merck's Keytruda as the world's best-selling drug. This represents adaptive radiation into adjacent niches: the same molecular architecture serving two massive patient populations. Full-year 2025 revenue guidance reached $63-63.5 billion, up from earlier estimates, as Lilly captured nearly 60% of injectable obesity/diabetes prescriptions—a first-mover advantage that Novo Nordisk's single-agonist Wegovy cannot match.

The mechanism mirrors yeast exponential growth in optimal conditions. Mounjaro revenue jumped 109% to $6.52 billion in Q3 2025, while Zepbound revenue increased 184% to $3.57 billion. International launches in China, Brazil, and India added fuel—resource allocation into virgin territories where competitors face regulatory delays. CEO David Ricks noted "really strong international performance," echoing how invasive species colonize new ecosystems faster than natives adapt. Phase 3 trials of orforglipron, an oral GLP-1, completed successfully across diabetes and obesity indications, with regulatory submissions planned by year-end. This pipeline diversification represents bet-hedging: if injectable supply constraints limit growth, oral formulations provide an alternative metabolic pathway.

Yet exponential growth cannot continue indefinitely—even bamboo forests reach nutrient limits. Lilly's 2024 revenue of $45 billion fell $400 million below October guidance, a rare stumble attributed to demand miscalculation. The company invests heavily in manufacturing capacity, announcing a $3 billion production site in Q3 2025 to prevent supply bottlenecks. This mirrors how fungi allocate resources to hyphal expansion when encountering rich substrate. Lilly's dominance in GLP-1 receptor agonists created temporary monopoly rents, but patent cliffs loom and biosimilar competitors evolve. The next test: whether Lilly's superior efficacy data—dual-agonist versus single—creates sufficient niche separation to maintain territorial control when cheaper alternatives emerge.