Tense? Regularly take garlic powder (4)
I believe the answer is:
talc
'powder' is the definition.
(talcing is a kind of powdering)
'tense? regularly take garlic' is the wordplay.
'tense?' becomes 't' (abbreviation used in many dictionaries).
'regularly take' indicates alternate letters (I've seen 'regularly taking' mean this).
The alternating letters of 'garlic' are 'alc'.
't'+'alc'='TALC'
(Other definitions for talc that I've seen before include "Softest substance in Mohs scale of hardness" , "Cosmetic powder" , "I may dust" , "Baby powder" , "Scented powder used after bathing" .)