Thanks! The Hyperlactation potion is locked behind two requirements: Alchemy Lab 1 and an unlocked farm. The reason for that is having a slave effected by Hyperlactation without a farm to milk them can end up with some serious health complications and massive stress. Try unlocking the farm and the Hyperlactation potion SHOULD immediately show up for you then (of course, let me know if it doesn't).
Are you in story or sandbox? I think I figured out what the issue is. There are 4 stages for the Farm story/unlock. It unlocks at 4, but I cannot recall exactly what that last phase is (I believe it has something to do with Sebastian, maybe 1 remaining quest?). I adjusted it so it'll unlock on 3 so it'll appear when you first get the farm (it'll change in version 0.9.3)