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, boosts the heart rate and supposedly enhances an athlete’s performance during a workout.

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.

Ultimate Orange contains ephedrine, a substance banned by the NCAA. A medical expert said asthma medication may increase the danger of such supplements.

“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 Wheeler, 22, died of bronchial asthma after collapsing on the practice field.

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

The source 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.”

“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 lists the ingredient “ma huang,” the Chinese name for the prohibited substance ephedrine.

The source 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 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.

Wheeler had his inhaler with him while he was running the test, Aggeler said. He said 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.

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

“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 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.

The Summer Northwestern’s Glenn Kasses contributed to this report.