Adult is a transformation in The Binding of Isaac, added in the Afterbirth+ DLC.
Obtained after consuming 3 Puberty pills.
+1 full Red Heart container.
Makes Isaac's voice deeper.
This page shows information as of the latest Repentance release.
To see latest up-to date information about this transformation for the new Repentance+ (Online Co-op) DLC, check this page instead.