Can they save you loss of hair? (5)

I believe the answer is:

locks

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'hair?' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

(Other definitions for locks that I've seen before include "Fastens - hair" , "Tresses" , "raising devices for sailors" , "Secure fasteners for doors" , "Secures; person's hair" .)

I've seen this clue in the Evening Standard.

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