Ryan Bailey tested positive for DMBA at the IBSF North American Cup in January ©Getty Images

Ryan Bailey, who came fourth in the men’s 100 metres at the London 2012 Olympic Games, has been given a backdated six-month doping ban after failing a drugs test earlier this year.

The United States bobsledder, who switched to the winter sport last year from athletics, was handed the sanction after testing positive for the banned stimulant dimethylbutylamine (DMBA) on January 10 at the International Bobsleigh and Skeleton Federation (IBSF) North American Cup.

His ban was confirmed by the United States Anti-Doping Agency (USADA) following a hearing of the American Arbitration Association, who accepted Bailey’s explanation that the positive test was caused by a “high-risk dietary supplement”.

Analysis of the supplement conducted at a World Anti-Doping Agency accredited laboratory in Salt Lake City confirmed it contained DMBA.

DMBA is a prohibited in-competition substance under USADA, the United States Olympic Committee national anti-doping policies and the IBSF anti-doping rules.

Warnings about the substance has been given by USADA in the past.

As a result of the backdated ban, the 28-year-old’s results from the six-month period starting on January 10 have been disqualified.

This includes a podium topping performance in the two-man event at the IBSF North American Cup and his sixth place finish in the four-man race.

Ryan Bailey, left, was part of the United States' 4x100m relay team who won silver at London 2012 before Tyson Gay's, second left, failed drugs test in 2013 saw them disqualified ©Getty Images
Ryan Bailey, left, was part of the United States' 4x100m relay team who won silver at London 2012 before Tyson Gay's, second left, failed drugs test in 2013 saw them disqualified ©Getty Images

At London 2012, Bailey clocked a personal best of 9.88sec in the first round of the men’s 100m.

He went onto reach the final and came fifth, equaling his personal best in the process, a result which was later upgraded to fourth following fellow American Tyson Gay’s disqualification after he failed a drugs test in 2013.

Bailey was also part of the US 4x100m relay team who won silver at the same Games, but was stripped of the medal follow Gay’s positive test.

Perhaps his biggest achievement on the track came at the 2015 International Association of Athletics Federations' World Relays in The Bahamas when Bailey held off the challenge of Jamaica's multiple Olympic gold medallist Usain Bolt to win the 4x100m race for his country.

Last year, following a series of injuries, Bailey turned his attention to bobsleigh and started training with the US team.

He made an almost immediate impact with a victory at the USA Bobsleigh's National Push Championships, an event which Gay also attended but ended up not taking part.