The terrorists who killed eight people, including two Australian women, in last year's London Bridge and Borough Market attack were pumped up on steroids, a pre-inquest hearing has heard.

Brisbane nanny Sara Zelenak, 21, and Loxton, South Australia, nurse Kirsty Boden, 28, died when the three men ploughed into pedestrians in a white van on the bridge then stabbed evening revellers in the nearby market with 12-inch ceramic knives.

Khuram Butt, 27, Rachid Redouane, 30, and Youssef Zaghba, 22, had all taken a substance called DHEA shortly before the attack on June 3 last year, London's Old Bailey court heard on Friday.

A toxicologist will be called to give evidence at their inquest next year after it was found levels in their systems were above the acceptable physiological range.