Khuram Butt, 27, Rachid Redouane, 30, and Youssef Zaghba, 22, had all taken a substance called DHEA shortly before the attack on 3 June last year, the Old Bailey was told.
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.
Eight people were killed when the three men ploughed into pedestrians in a white van on the bridge and then stabbed evening revellers in the nearby market with 12-inch ceramic knives.
The victims were: Canadian Christine Archibald, 30, Frenchmen Xavier Thomas, 45, and Alexandre Pigeard, 26, as well as Sara Zelenak, 21, Kirsty Boden, 28, Sebastien Belanger, 36, James McMullan, 32, and Ignacio Echeverria, 39.
The attackers were shot and killed by police at the scene.
Chief Coroner Mark Lucraft QC said he hoped the inquests would provide grieving families with answers and give “comfort in such difficult circumstances”.
Jonathan Hough QC, counsel to the coroner, said the inquests were of great public importance and would be “full, rigorous and fair”.
Some 1,800 witness statements have already been taken for the inquests.
Among those to be represented are the security services, police, fire authority and ambulance service as well as the families of both victims and attackers.
The inquests would examine what MI5 knew about Butt before the attack, the court heard.
The coroner ordered the inquests into the three knifemen be heard separately to their victims during the pre-inquest hearing attended by family members.
He said he would first hear the inquests into the deaths of the victims at the Old Bailey in early 2019 followed by a jury inquest into the deaths of the attackers.
Lawyer Victoria Ailes, representing five of the victims’ families, said they were particularly concerned to find out about any CCTV footage or mobile phone film showing the attacks on their loved ones.
Lucraft ordered that any applications for anonymity in the inquests, including from two families of the attackers, be made in advance.