Certain hormone is implicated in my mood (9)

I believe the answer is:

cortisone

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

'certain hormone' is the definition.
'cortisone' can be an answer for 'hormone' (cortisone is a kind of hormone). I am not certain of the 'certain' bit.

'is implicated in my mood' is the wordplay.
'implicated in' means one lot of letters goes inside another.
'my' becomes 'cor' (both are expressions of surprise).
'mood' becomes 'tone' (tone is a kind of mood).
'cor'+'tone'='cortone'
'is' going inside 'cortone' is 'CORTISONE'.

Can you help me to learn more?

(Other definitions for cortisone that I've seen before include "hormone used in medicine!" , "Drug" , "Steroid" , "anti-inflammatory one" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.