No patients have opted for a living donor transplant since the procedure became available last year.
A survey of patients suitable for transplant, by a team led by Stirling University, found they felt they "couldn't live with themselves" if anything happened to the donor as a result of the operation.
The risk of death for liver donors is about one in 200 - in kidney donations, it is one in 3,000. At least one in five liver donors will experience health problems.
The survey findings were presented by Stirling researcher Lesley McGregor at the Division of Health Psychology conference at the University of Nottingham.
Ms McGregor, who worked with researchers from Edinburgh Royal Infirmary, said: "The patients didn't want their loved ones to donate because they knew they would have to give up approximately two thirds of their healthy liver, with roughly a one in 200 chance of death.
"But the potential donors just wanted to help their ill relative, irrespective of the risk," Ms McGregor said.
She added: "These results are important, as we need to achieve a deeper understanding of the attitudes, concerns and risk perceptions of patients and their families."
The living donor liver transplantation programme was introduced at the Scottish Liver Transplant Unit at Edinburgh Royal Infirmary in April 2006. It was the first time the procedure had become available on the NHS but so far no patients in Scotland have taken the option, Ms McGregor said.
The procedure avoids a long wait for a liver from someone who has died. Delay can lead to complications after the transplant.