"Bullhead," Directed by Michael R. Roskam "My whole life I've known nothing but animals," declares Jacky Vanmarsenille (Matthias Schoenaerts), the tragic and scary protagonist of "Bullhead." Jacky, who is addicted to anabolic steroids, is a bulky, half-handsome, slightly misshapen lug who runs his family's cattle farm in Limburg, in the Flemish region of Belgium. Part character study, part crime thriller, "Bullhead" is the impressive but deeply flawed first feature written and directed by Michael R. Roskam. The movie is an Oscar nominee this year for best foreign language film. Although he is not a prizefighter, Jacky, when riled up, is every bit as fearsome as Robert De Niro's Jake LaMotta in "Raging Bull." Violently head-butting antagonists while emitting primal grunts and gasps, he goes out of his mind when in a fury. At home alone he injects the most potent steroids his dealer can provide and shadowboxes while ignoring warnings that combining the drugs with alcohol will destroy his liver in a week. In Mr. Schoenaerts's gripping, anguished performance, Jacky is a man jumping out of his skin. The movie begins with a solemn narrator who intones, "Sometimes in a man's life stuff happens that makes everyone go quiet, so quiet that no one even dares talk about it, not to anyone, not even to themselves." I won't say what happened to Jacky, which is shown in a sickening flashback midway through the film, except that it explains his behavior and has a deepening metaphorical resonance as the story continues. "Bullhead," at heart, is about testosterone. An excess of it in humans, some say (and the movie seems to agree), is responsible for many of the horrors of the world. Before Jacky started taking steroids, which he shoots and gobbles by the fistful, the Vanmarsenille family business was injecting its cattle with illegal drugs to make them grow larger and more quickly. The overly complicated story, partly inspired by the 1995 killing of a Belgian government veterinary inspector, begins when Jacky is pressured to make a deal with a mob-connected meat seller. But the recent murder of a police officer investigating the "hormone mafia" makes him hesitant. With an investigation under way, the criminals are desperate to dispose of the shooter's car, which has a bullet hole and new tires. Complicating matters, Jacky's estranged best friend from childhood, Diederik (Jeroen Perceval), now an assistant to the hormone trafficker, is a reluctant police informant. Twenty years earlier Diederik witnessed the incident that traumatized Jacky but was coerced into silence. Even though the movie's two main aspects - Jacky's plight and the criminal activity - involve steroids, they don't mesh. As the crime story develops, it turns into a far-fetched quasi-incestuous drama that leaves frustrating holes in the narrative scheme. Jacky's wary pursuit of the sister of a childhood enemy adds an odd wrinkle to the story, as does the grown-up Diederik's romantic obsession with a handsome police investigator. But "Bullhead" sustains a menacing noirish ambience. The scenes of Jacky's silhouette while shadowboxing have an almost metaphysical dimension. The dark, beautiful landscape shots with towering clouds evoke an imminent storm. When the movie is focused on Jacky's desperate and futile efforts to be a superman, it becomes a stark tragedy of masculinity and its chemical boundaries. "Bullhead" is rated R (Under 17 requires accompanying parent or adult guardian). It has nudity and scenes of extreme violence. Bullhead Opens on Friday in New York, Los Angeles and Austin, Tex. Written and directed by Michael R. Roskam; director of photography, Nicolas Karakatsanis; edited by Benoit De Clerck; music by Raf Keunen; produced by Bart Van Langendonck, Peter Bouckaert, Patrick Quinet and Jan Van der Zanden; released by Drafthouse Films. In Dutch and French, with English subtitles. Running time: 2 hours 6 minutes. WITH: Matthias Schoenaerts (Jacky), Jeroen Perceval (Diederik), Barbara Sarafian (Eva), Jeanne Dandoy (Lucia), Tibo (Antony) and Sam Louwyck (Marc).