Rashidi Wheeler, a Northwestern football player who died Aug. 3 after preseason conditioning drills, may have been taking a supplement banned by the NCAA, a source close to the situation said Friday.

The supplement, Ultimate Orange, contains the prohibited substance ephedrine. Supplements containing ephedrine boost the heart rate and supposedly enhance an athlete’s performance during a workout.

“It’s proven that they are quite dangerous,” said Michael Fotis, the manager of drug information at Northwestern Memorial Hospital.

A preliminary autopsy concluded that the Wheeler, 22, died of bronchial asthma after collapsing on the practice field. The combination of Ultimate Orange with asthmatic medication may increase the dangers of the supplement.

“It could complicate things,” Fotis said. “It would be a foolish thing to do.”

The source close to the situation said that Wheeler may have taken Ultimate Orange the day he died.

“I’ve never seen him take something,” he said. “But I’ve heard he used them on that day.”

The Los Angeles Times reported Saturday that, while it is unknown whether Wheeler took the supplement Aug. 3, unnamed players said he did use it in the months preceding his death.

One former player told The Daily Friday that Ultimate Orange is widely used on the NU football team. “For a game, it depends on who the starters are,” he said. “But I’d say on any given day for a game you’d probably have 12 to 15 players taking it.”

The company Next Proteins originally produced Ultimate Orange in both capsule and powder form for mixing in drinks. While the capsule was discontinued several months ago, the company stopped producing the powder form at the end of May, according to Next Proteins president David Jenkins.

“It was relatively popular,” Jenkins said in an interview Friday. “But it’s not the focus that we want for what we want to be doing in the future.”

Jenkins said the company chose to focus its resources into another line of products. Remaining bottles of Ultimate Orange were still available in stores after Next Proteins stopped producing it. A General Nutrition Center store at 1723 Benson Ave. in Evanston only sold its last bottle a week ago, according to store manager Klaer Twist.

The label on Ultimate Orange contains the ingredient “ma huang,” the Chinese name for ephedra. Jenkins insisted that ephedra and ephedrine are two different substances, referring to ephedrine as a “synthetic chemical” and ephedra as an “herb composed of a variety of alkaloids.” He declined to elaborate on the functional difference between the two.

Fotis said the substances should be considered essentially the same.

“Those are all different terms for ephedrine,” he said. “They may have other things in them, but ephedrine is thought to be the main ingredient. They are really parsing the language there.”

The source close to the situation said coach Randy Walker and head trainer Tory Aggeler have told players not to take Ultimate Orange, although he said he didn’t think Walker knew of the team’s use of the supplement.

He said a nutritionist told the team several years ago that “several people had died” as a result of using the substance.

Players using Ultimate Orange know how to pass drug tests without being detected, the former player said.

“There are ways to get around them,” he said. “If you’ve been around the system long enough, you understand when the drug tests are coming up.

“The only one you really know about is the preseason, when you report. And even that, if you’re really doing something, you just time it out.”

The source close to the situation said that a player could take Ultimate Orange before a workout, and the substance might be flushed out of the system within four to six hours.

The conditioning test that Wheeler and about 60 other players were trying to complete Aug. 3 consisted of a series of progressively shorter sprints, all run within just over 10 minutes.

Aggeler said at a press conference immediately after Wheeler’s death that the asthmatic had his inhaler with him while he was running the test. Aggeler added that the asthma attack that preceded Wheeler’s death did not at first seem unusual from any of the 30 attacks he had suffered before.

The former player said that Wheeler regularly had difficulty with the drill and usually struggled with asthma attacks after completing it.

“They were bad,” he said. “There were times where he’d lay out there for a half-hour, 45 minutes after we ran just trying to catch his breath and get his strength to walk back into the locker room.”

The source close to the situation said it is not unusual for a large number of athletes to rest on the ground after completing the grueling test.

Wheeler’s mother, Linda Will, has expressed concern that the training staff on hand was not sufficient to attend to the number of players on the ground after the drill.

William Banis, vice president for student affairs, is heading an investigation into the events surrounding Wheeler’s death.