Sports scientist Stephen Dank says he never administered a single product or substance to any athlete without the prior consent of ASADA or WADA.

The Australian biochemist has worked with NRL and AFL clubs for two decades in a number of capacities, including high-performance consultation, technical analysis and the provision of supplement programs. Dank's tenure at Cronulla, Manly and Essendon has come under particular scrutiny, and those clubs were named in the Australian Crime Commission's report into doping and the integrity of sport.

Stephen Dank: Intimate knowledge of drugs code. Credit:ABC TV

However, Dank said the Australian Sports Anti-Doping Authority had approved all of his products and methods, and he had never gone outside those boundaries.

''Before I've done anything in any forum, we have always had conversations with WADA [the World Anti-Doping Agency] or ASADA - or in some cases both,'' Dank told Fairfax Media.