It took me a long time to dredge this one up. You are thinking of the 1994 TV movie
Island City. A plot summary from someone else who was looking for this: "I saw this color movie in the 90's on television in the US. It takes place sometime in the future where a drug was created that can stop the aging process. The problem is that it only worked for certain humans. Other humans were mutated by the drug and forced to live in the barren wastelands outside of the city. Something memorable of note is that before starting a relationship, each person must check wether a jewel, located on their hands I believe, matches in color to the other person's jewel. This is to prevent further mutants from being born. One of the main characters was a half mutant whose jewel color is black which is unique. Another of the main characters has a husband who did not take the drug for fear of becoming a mutant and is now an old man. The plot involves a group of forever young people going outside of the city to look for non-mutants. They find a woman who ends up being the long lost sister of someone in the city and bring her back."