Please advise if Alen is a Muslim baby boy name

Alen is a variant of Alan, which is a name that is possibly originated from the Alans, who were a group of nomadic tribes living in the Caucasus region between the Black Sea and the Caspian Sea, an area that today belongs to Russia.

It might also have come from Proto-Indo-European with the meaning "deer".

I do not know of any Islamic origin for a name like Alen, but since the non-Islamic origins do not contain bad meanings, Muslims can use the name Alen, Alan or their other variants.