Which has a longer 1/2 life Nandrolone decanoate or Nandrolone undecylate. I'm finding conflicting data.

[Cherokee]

The chart you posted lists undecylenate and undecanoate. Undecylenate and undecylate are 2 different things. The "en" portion in undecylenate denotes the presence of a double bond (an alkENe), this case at the end of the aliphatic tail. This double bond shortens the half-life since the carbon next to it is more easily oxidized and cleaved due to the presence of the double bond.

That explains a lot Thank you very much