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”).

Zogenix, Inc.’s (ZGNX) rating falls this week to an F (“strong sell”), down from last week’s D (“sell”). Zogenix is a pharmaceutical company commercializing and developing products for the treatment of central nervous system disorders and pain. In Portfolio Grader’s specific subcategory of Equity, ZGNX also gets an F. As of Jan. 16, 2015, 15.4% of outstanding Zogenix, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of ZGNX stock.

Alcobra Ltd.’s (ADHD) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. The stock gets F’s in Earnings Momentum, Equity and Cash Flow. To get an in-depth look at ADHD, get Portfolio Grader’s complete analysis of ADHD stock.

Lipocine, Inc. (LPCN) experiences a ratings drop this week, going from last week’s D to an F. Lipocine is engaged in the development of pharmaceutical products in the areas of men’’s and women’’s health. The stock gets F’s in Earnings Revisions, Equity and Cash Flow. For more information, get Portfolio Grader’s complete analysis of LPCN 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.