Right-to-die campaigner Paul Lamb, who wants a doctor to help him die in a dignified way, was not present for the reading of the unsuccessful ruling at the Court of Appeal.
The ruling was made by the Lord Chief Justice Lord Judge, Master of the Rolls Lord Dyson and Lord Justice Elias in London.
The trio had heard argument that people who are too sick or disabled to end their "unbearable" lives without help are currently being condemned to "suffer in silence or make desperate attempts to kill themselves".
Mr Lamb, 57, from Leeds, had won the right to join the litigation to continue the battle started by Mr Nicklinson, who died at home last August, a week after he lost a High Court bid to end his life with a doctor's help.
Locked-in syndrome sufferer Tony Nicklinson's widow and a paralysed victim have pledged to continue to challenge right-to-die law.
Locked-in syndrome sufferer Tony Nicklinson campaigned for years to win the right to end his life. Here is the timeline of his struggle.