Richard Freeman, a former doctor at Team Sky and British Cycling, looked into the relationship between testosterone and endurance exercise, the medical tribunal assessing his fitness to practise heard on Wednesday.

According to British newspapers The Times and Daily Mail, it was revealed Freeman downloaded academic papers to his laptop, one concerning the effects of Viagra, the other the effect of endurance exercise on testosterone levels.

The article on Viagra, a sex drive-booster that's said to increase testosterone levels, was downloaded in April 2011, a month before Freeman ordered 30 sachets of testosterone gel to British Cycling and Team Sky headquarters.

Testosterone is banned in and out of competition and the delivery is at the centre of the tribunal, concerning all four of the allegations – out of 22 – that Freeman is contesting.

Freeman, who previously denied ordering the Testogel, is fighting the charge he 'knew or believed' it could be used to dope an athlete, instead claiming it was intended for erectile dysfunction treatment for former coach Shane Sutton. Sutton vehemently denied the accusation, along with any knowledge of the delivery, before storming out of the tribunal last week.

The hearing resumed on Wednesday, when the GMC called on professor David Cowan, a leading anti-doping expert who was formerly director of the WADA-accredited Drug Control Centre in London.

"It indicated a lot of knowledge and an interest of testosterone concentration in riders," Cowan said of the laptop documents that had been seized by investigators.

"Certainly concern was expressed that particular cyclists had lower levels of testosterone than normal, but there was no indication of any treatment for that, other than rest."

According to reports, Freeman's lawyer, Mary O'Rourke QC, questioned Cowan's capacity to comment on the medical uses for testosterone, before arguing Freeman would have had to have robust knowledge of the hormone, given it's a banned substance that's tested for regularly.

The tribunal continues on Thursday.