All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.

 

Dyeing hair with black, not any other color, is forbidden because the Prophet (PBUH) said: "Avoid black". Jabir b. 'Abdullah reported that Abu Qubafa was led (to the audience of the Holy Prophet) on the day of the Conquest of Mecca and his head and beard were white like hyssop, whereupon Allah's Messenger (PBUH) said: Change it with something but avoid black." {Related by Muslim}. 

Scholars are agreed that it is permissible for a man to dye his hair with Wars and saffron, in addition to other dyes excluding the black. Narrated Abu Dharr: The Prophet (PBUH) said: "The best things with which grey hair are changed are henna and katam." {Related by Abu Dawoud}.

In addition, Ar-Ramli (May Allah have mercy on him) says: "It is recommended to dye hair with red and yellow, but it is forbidden to dye it with black except for the purpose of Jihad." {Nehayat al-Mohtaaj, vol./8pp.140}.

In conclusion, you (Asker) are permitted to dye your hair with any shade of brown provided that it doesn`t reach the degree of black. And Allah The Almighty Knows Best.