Code Name wa Baby Face

Code Name wa Baby Face follows middle-school student Dan Nanami, who's actually a spy from a European country. With drugs called Soma, he can turn into adult for 77 minutes. While in adult form, his fighting ability increases dramatically and a special ability allows him to easily obtain information from women. Later on, he's joined by others who have similar abilities to his.

(Source: MU, edited)

Included one-shot:
Volume 2: Code Name wa Baby Face (pilot)