I currently don't know how Mutagens work, exactly... Have picked one up in Inventory, but haven't used it yet. Going from the Game Manual (There's no mention of Mutagens in the Game Guide) we're told that "The mutation cannot be reversed" and that mutagens come in 3 forms (lesser, basic, greater).
However, I would reckon that, although a Mutation cannot be reversed, a different Form can be applied. For example, if you apply a Lesser Range Mutagen at one point, then pick up a Greater Range Mutagen, you'll be able to apply that Form over the one currently used, but you can't change the type of Mutagen (Ranged) to something else. So, Mutagens can't be changed, but can be upgraded. Like I say though, don't know if this is the case for definite... if anyone has a Lesser+Basic mutagen of the same type (or Basic+Greater) they could test it out, see if this is the case.
Also, there is a List of the Mutagen types, in the Instruction Manual (do people no longer read these things?). It doesn't give specific stats, just the types of Mutagen that are available.
Post edited May 18, 2011 by Unacosamedarisa