For almost a decade, US men were faced with TV, online ads and billboards about the risks of low testosterone or ‘low T’, as it was branded.

Eventually, in 2014, the Food and Drug Administration (FDA) issued a safety warning about the potential link between testosterone treatment and cardiac events.

This noted that testosterone was only approved for specific medical disorders and that treatment benefits and safety had not been tested “for the treatment of low testosterone levels due to ageing”, including for symptoms seeming to be related to low testosterone.

The FDA also insisted that the companies “clarify the approved uses” of testosterone and the ‘low T’ advertising ended basically overnight, said Sydney researcher Professor Barbara Mintzes.