Episode 46 of The Trigan Empire
The Elixir of Youth
aka The Youth Serum
Het elixer (Dutch title)
The Elixir (Dutch title, translated)
Written by Mike Butterworth
Illustrated by Philip Corke
The Elixir of Youth was originally published in 8 instalments in issues 645 (25 May 1974) to 652 (13 July 1974) of Look and Learn magazine.
It is reprinted in Volume 4 of The Rise and Fall of the Trigan Empire (Rebellion).
Plot summary (Dutch)
MediaFire via British Comics Compilations