Hi snowhite48 and welcome to NeuroTalk!
I've heard of 4-AP but couldn't afford both it and the LDN....and I was doing well on just the LDN so I didn't bother to try it. You might want to start a thread about 4-AP on the MS forum. You might get more responses if you post there, too.
Glad you've joined us here. It's a great group.