Shares of Eli Lilly (LLY -2.40%) lagged the broader market in 2013 by a wide margin. While some investors may see this as an opportunity to jump into a sector filled with sky-high valuations, it's important to first weigh both the pros and cons of this particular stock. In the following video, analyst Max Macaluso focuses on one headwind, namely the affect of the "patent cliff" on Lilly's top and bottom lines, and one tailwind, the drugs Lilly is developing, that will have huge impacts on the stock this year.