Bayern Munich club doctor Hans-Wilhelm Muller-Wohlfahrt has said performance-enhancing drugs make no sense in football and again hit out at the club's former coach Pep Guardiola.
Speaking to Die Zeit, he said doping a player would result in a drop in performance in the following match.
Asked whether he had ever encountered performance-enhancing drugs in football, Muller-Wohlfahrt said: "No, not at Bayern or the national team.
"It would make no sense to bulk up in football -- the muscles would become too heavy. They'd lose elasticity.
"If a player were to take stimulants, his batteries would be empty after that and he would experience a drop in performance in the following match.
"As far as I can oversee it, there is no doping in football."
Late ron Thursday, Germany's national anti-doping agency contradicted Mueller-Wohlfahrt's claim.
NADA told the Rheinische Post that doping has benefits for players.
The agency said: "It's about speeding up recovery in football, treating injuries faster and more effectively, and reducing convalescence. If prohibited substances and methods are used, then that's also doping."
NADA said there is more to doping than use of anabolic steroids or stimulants, "therefore doping in football cannot be excluded from NADA's point of view."
Muller-Wohlfahrt again touched on the clash with Guardiola which led to his departure in the aftermath of a Champions League quarterfinal defeat at Porto in 2015.
"I had been at Bayern for 38 years without any problems," the 75-year-old said.
"And suddenly a 44-year-old coach joins, someone who has not walked this earth for much longer than I had been Bayern team doc, someone who knows everything, who suddenly puts pressure on and accuses me that an injury layoff after a severe ligament injury takes six to seven weeks rather than four weeks like in Spain."
Asked whether that meant there were doctors with other treatments in Spain, Muller-Wohlfahrt said: "I don't have any insight into their work.
"Thiago [Alcantara] once returned from Spain after four weeks, seemingly fit. But when I examined him, I said: 'Stop! The injury has not healed completely, even though you are pain-free.'
"Guardiola still allowed him to train. Thiago got injured again and went on to miss a full year."
Information from the Associated Press was used in this report