Lilly has invested billions of dollars to ramp up production capacity.Eli Lilly (LLY -1.74%) sells treatments for a wide variety of therapeutic areas, but one portfolio in particular has driven major gains in recent times. And that's the company's weight loss drugs. Lilly sells the compound tirzepatide under two different names -- Mounjaro for type 2 diabetes and Zepbound for weight loss. But doctors have prescribed either for the weight loss indication. These drugs have become blockbusters, bringing in mor ...