Age Magic (エージ メージク eeji meejiku) is a type of Caster Magic, Holder Magic, and Lost Magic that allows the user to essentially "adjust the clock" on their physical bodies, granting them a desired body; either a younger or older form. This magic was outlawed because of the abuse of many users keeping themselves physically young for years until they died. Unfortunately, the magic cannot actually return a wizard to youth nor can it accelerate someone to death. It simply gives the user a physical alteration of their bodies. The magic was outlawed out of both fear and morals, since one could essentially deceive anyone they came across by altering their bodies repeatedly. It was also outlawed because constant use of the magic would disfigure the user should it be used excessively.
In the case of Falaranion Capolom: Because Falaranion doesn't use his magic to switch back and forth between his true form and his younger form often, his body hasn't taken on any disfigurements. However, it does create strain on his body as the spell alters his form. Compacting mass into a smaller body is not good for anyone.