Energy with current compound (7)
I believe the answer is:
peptide
'compound' is the definition.
(peptide is a kind of compound)
'energy with current' is the wordplay.
'energy' becomes 'pep' (personal energy, vim).
'with' means one lot of letters go next to another.
'current' becomes 'tide' (sea currents).
'pep'+'tide'='PEPTIDE'
(Other definitions for peptide that I've seen before include "Amino acid compound" , "Substance in body" , "Biochemical compound needed" .)