Jumbo-Visma rider Michel Hessmann's B-sample has also tested positive for a diuretic, meaning the German now faces a ban from cycling, according to a report in Badische Zeitung.
The 22-year-old was provisionally suspended by his team when the news emerged in August that he had tested positive in June for "a diuretic that was contained in a medication."
Badische Zeitung has reported that analysis of the rider's B-sample has now confirmed the initial positive, which was taken in an out-of-competition test on June 14. The German Anti-Doping Agency announced the news at the request of the newspaper.
The drug involved in the positive case has not yet been disclosed by Jumbo-Visma, Hessmann, or the German Anti-Doping Agency.
Under WADA rules, Hessmann faces a ban from competition of four years if he can't give any explanation for the presence of the diuretic. His ban could, however, be reduced to two years if he can prove that he tested positive due to a contaminated supplement or food.
German authorities opened an investigation into Hessmann following the positive test, searching his home and seizing phones and computers in late August. Athletes caught using or administrating doping products face a criminal sentence of up to three years in Germany, though no athlete has yet served any jail time for the offence.
Hessmann turned professional with Jumbo-Visma in 2022 after coming up through the team's Continental development squad.
He finished third in the Tour de l'Avenir last season and went on to make his Grand Tour debut at the Giro d'Italia this spring, helping Primož Roglič to overall victory in Rome.
His positive test came soon afterwards in mid-June, though he continued racing at the German National Championships, Czech Tour, and Road World Championships before the news of the positive emerged.
Hessmann's final race before his provisional suspension was the World Championships in Glasgow, where he failed to finish on his debut at the elite road race.
