Is it permissible to shave the armpit hair using a razor?
All praise be to Allah Alone, and peace and blessings be upon His Messenger, and his family and Companions.
Yes, it is permissible, because what is required is to remove the armpit hair, whether by plucking, shaving or some other method. However, plucking is better if it is easy to do so, because the Prophet (peace be upon him) said:
“Five (practices) correspond to the Fitrah (natural disposition): circumcision, removing the pubic hair, trimming the moustache, clipping the nails, and plucking the armpit hair.”
(Agreed upon by Al-Bukhari and Muslim)
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.