Jamaican sprinter Nesta Carter tested positive for a banned substance, but Usain Bolt is taking the biggest hit.

News broke Wednesday that the Jamaican 4x100-metre relay team that won gold at the 2008 Beijing Olympics is being stripped of its medal after a re-analysis of Carter's sample turned up the banned stimulant methylhexaneamine

The failed test by Carter, who ran the opening leg of the relay, spoiled Bolt's perfect "triple-triple" record — he won gold in each of his three events at three consecutive Olympic Games.

Meanwhile, the ruling by the International Olympic Committee has raised several questions, including: What is methylhexaneamine? How much might Carter's use of the drug have affected the results of the race? And is there a chance for a successful appeal?

We went to the experts for some answers.

How does methylhexaneamine work?

Blue Jays star Marcus Stroman, former Jay Chris Colabello, boxer Brandon Rios and South African discus thrower Victor Hogan are among the athletes who have been disciplined for methylhexaneamine use in recent years.   

According to Dr. Greg Wells, a kinesiology professor at the University of Toronto, the stimulant is similar in composition to drugs like ephedrine which can be found in a number of over-the-counter medications, as well as in athletic supplements that don't always list every ingredient on their packaging.

The physiological effects of the drug can be compared to those of a non-drowsy cold formula. 

"It feels like you have a bit of adrenaline surging through your body," says Wells. "The effects of that type of stimulant become especially significant in a sport like track and field where hundredths of a second can make a difference."  

While not to be confused with an anabolic steroid, which causes significant structural changes inside the body, Wells says the stimulant can be dangerous, and can put athletes at an advantage because of its ability to: 

  • open airways in the lungs, making it easier to take in oxygen 
  • narrow blood vessels, which increases blood pressure, helping push oxygen to body tissue 
  • cause water to be expelled from the body, which can lead to weight loss

Although stimulants like methylhexaneamine can cause an instantaneous boost, Wells says if the drug was in a supplement Carter was using on a regular basis, "he would incur a consistent advantage in training, meaning he could work harder, more often, more easily, which may be a significant benefit."

Why did it take so long to catch Carter?

Methylhexaneamine was not specifically named on the banned substance list back in 2008, but being caught using it is still considered a doping infraction because the properties are associated with other substances in the stimulant class.  

Paul Melia, president and CEO of the Canadian Centre for Ethics in Sport, says the creators of designer drugs are always one step ahead of drug detection labs, making the ability to test athletes retroactively very important.

"Designer drugs are created in clandestine labs that have the ability to make changes to the molecular makeup of a drug," Melia says. "The drug-test laboratories need to know the molecular structure of a banned substance in order to detect it.

"Fortunately, now the IOC is storing samples for up to 10 years, giving we in the lab time to identify these new substances that are coming onto the market. Since 2008, the lab has identified this stimulant, giving us the analytical techniques to detect it."

Can Carter appeal?

Carter could face a ban of at least two years, which may be a crushing blow to the career of the 31-year-old sprinter.

Melia says that if it can be proven that a drug was deliberately and intentionally used to enhance performance, the sanction can increase to as much as four years. But if Carter can demonstrate that he took the drug unknowingly, his punishment can be argued down to as little as a warning.

As far as Carter's (and Bolt's) relay medal goes, Melia says that although Carter will have the opportunity for a hearing to presumably try to reduce his sentencing, it won't have any impact on the decision to strip the gold from his relay team.

"I think it's a really powerful deterrent for athletes who might be thinking about using designer drugs that can't be detected today," Melia says. "It's not going to give them much comfort when they hear a story like this that goes right back to 2008."