Stimulant deep in her circulation (9)

I believe the answer is:

ephedrine

I'm a little stuck... Click here to teach me more about this clue!

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

'deep in her circulation' is the wordplay.
'deep in her' anagrams to 'EPHEDRINE'.
Though, I am unsure how the anagram is indicated.

Can you help me to learn more?

(Other definitions for ephedrine that I've seen before include "Bronchitis/asthma drug" , "Stimulant" , "Drug used for asthma and hay fever" .)

I've seen this clue in The Daily Express.

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