Helpful if you're patient (8)

I believe the answer is:

curative

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'helpful' is the definition.
(thesaurus)

I cannot understand how the remainder of the clue works.

(Other definitions for curative that I've seen before include "Restoring to health" , "health-giving" , "Therapeutic" , "Medicine" , "Healing" .)

I've seen this clue in the Evening Standard.

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