Eli Lilly and Novo Nordisk are the two biggest names in the pharmaceutical sector, but I see one as the clear-cut winner for investors.

Novo Nordisk ADR (NYSE: NVO) currently trades at $89 per share, nearly 40% below its peak level of over $145 seen in June of this year. In contrast, its closest peer, Eli Lilly stock is down 15% over this period.

Lilly and Novo still dominate the market for weight-loss and diabetes drugs, but the race is heating up in more ways than one.

Amidst a race with its competitors to produce the next smash-hit weight loss drug, Novo Nordisk's (NYSE: NVO) stock crashed by 19% on Dec. 20, after the company reported results from a late-stage clinical trial that it framed as a success.

As of 11:05 a.m. ET, Novo Nordisk stock is down a disheartening 20.8%, while both Lilly and Viking stocks are up 4.4% apiece.