The cobalt saga has already had a major impact on Sam Kavanagh's training career but perhaps an even bigger one on his personal life.

Kavanagh has spent several days at a Racing NSW inquiry into cobalt use sparked by high levels found in a post-race sample from Midsummer Sun after he won the Gosford Cup in January.

Since then, Kavanagh has been charged with multiple offences and, at the end of February, he named Flemington Equine Clinic vet Dr Tom Brennan as the source of a substance called Vitamin Complex later found to contain around 175 times the normal level of cobalt in a supplement.

Kavanagh's lawyer, Tony Hartnell, told the Racing NSW inquiry on Thursday his client had made mistakes but should not receive a life sentence.

"Sam Kavanagh is a young trainer who was going too fast," Hartnell said.

"He put his faith in the vet.

"He made stupid mistakes. His decisions mean his business credibility is destroyed.

"It has had a huge impact on his young family. His relationship with his partner has struggled and so has that with his parents.

"He now has to climb back from this."

Brennan, a long-time friend of Kavanagh has also been charged by Racing NSW stewards and their Victorian counterparts who are conducting their own investigations into five trainers, including Kavanagh's father Mark Kavanagh.

At a separate hearing this week, senior Australian Turf Club executive Matt Rudolph was asked to show cause why he should not be penalised for his conduct in trying to influence Sam Kavanagh to change his evidence against Brennan.

Rudolph and Mark Kavanagh arranged a meeting at a Sydney hotel with Sam Kavanagh who told the hearing he felt he had been ambushed and described his relationship with his father as fractured.

Brennan has since recanted his original evidence to Racing NSW stewards and admitted he supplied the Vitamin Complex but said he was assured it did not contain any prohibited substances.

Hartnell asked the panel to put a time frame on any penalty for Sam Kavanagh that would allow him to return to training.

"I am asking you to frame a penalty to he has some chance to come back," Hartnell said.