The ratings of three Pharmaceutical stocks are down this week, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

VIVUS, Inc.’s (NASDAQ:VVUS) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. VIVUS is a biopharmaceutical company engaged in the development and commercialization of therapeutic products for large underserved markets. VVUS also rates an F in Portfolio Grader’s specific subcategory of Equity. The stock price has dropped 16.8% over the past month, worse than the 1.3% decrease the Nasdaq has seen over the same period of time. As of Sept. 13, 2013, 30.5% of outstanding VIVUS, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of VVUS stock.

The rating of Cempra, Inc. (NASDAQ:CEMP) slips from a C to a D. Cempra manufactures and markets pharmaceutical products. The stock gets F’s in Equity and Cash Flow. For a full analysis of CEMP stock, visit Portfolio Grader.

Corcept Therapeutics Incorporated. (NASDAQ:CORT) earns an F (“strong sell”) this week, moving down from last week’s grade of D (“sell”). Corcept Therapeutics engages in the discovery, development, and commercialization of drugs for the treatment of severe metabolic and psychiatric disorders. The stock gets F’s in Equity and Cash Flow. For more information, get Portfolio Grader’s complete analysis of CORT stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.