All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
There is no objection to pray to Allah to bless you with good hormones and preserve them for you, and to keep you healthy. As for being certain that the supplication will be answered, it is recommended based on the Prophet’s sallallahu ‘alayhi wa sallam saying: “Supplicate Allah while you are certain of the answer, and know that Allah does not answer the supplication of a heart that is unmindful and distracted.” [At-Tirmidhi and others, and Sheikh Al-Albani graded it as Hassan in Saheeh Al-Jami’]
Allah knows best.