Put new energy into troubled lives -- one gets little thanks getting involved (8)
I believe the answer is:
vitalise
'put new energy into' is the definition.
'troubled lives one gets little thanks getting involved' is the wordplay.
'troubled' indicates an anagram.
'one' becomes 'i' (Roman numeral).
'gets' is a charade indicator (letters next to each other).
'little thanks' becomes 'ta' (short way of saying 'thank you').
'getting involved' indicates putting letters inside.
'lives'+'i'='livesi'
'livesi' anagrammed gives 'vilise'.
'vilise' going around 'ta' is 'VITALISE'.
(Another definition for vitalise that I've seen is " Stimulate activity".)