Shots at Vitamin B-12 are totally the new coke! Last night, while introducing Madonna into the Rock 'n' Roll Hall of Fame, Justin Timberlake said that Madge once plunged a syringe of B-12 into his ass to help him beat a case of fatigue. Lying pitcher and one-time Hall of Fame candidate Roger Clemens claims he too was getting regular ass injections of the vitamin. Anna Nicole Smith even had the stuff in her system at the time of her death! So what does B-12 actually do, other than make you the type of person who walks around with a bag full of needles (Madonna) or the type of person who needs a legal cover to hide the fact that you're using steroids (Roger)?

According to this no-doubt infallible, board-certified Slate "Explainer" column, Vitamin B-12 has come into vogue in the Kabbalah/cheater sect for its energy-boosting, anti-aging, performance-enhancing properties. The effects of an injection are similar to those of a caffeine pill. However, while a B-12 deficit can cause anemia and fatigue, particularly in senior citizens, loading up on the stuff Madonna-style likely provides no added benefit.

A more likely reason the vitamin is enjoying a moment: It's a really pretty shade of red, making it perfect for people whose health decisions are often grounded in superficiality. Like celebrities.