It's the same stuff, only difference is inactive ingredients. You might be allergic to some of them, hence changing brand might help but other than that minoxidil is minoxidil. I used qgain foam.
i was told by a top doctor/scientist in the field that yeah, its slightly better. tbh we may have been talking about finasteride at the time (which i dont take...) but his point was that generics can cheap out in those inactive ingredients or the production in ways that make them sightly less effective.
that said generic minoxidil is so much cheaper than rogaine its ridiculous. so what i do is use 25% rogaine and 75% generic minoxidil.
I think for liquid it probably doesn't matter since it is 4 ingredients. For foam I would use Rogaine since they developed the stuff and did a study to compare so probably have the best formula.
minoxidil is minoxidil. Use clean minoxidil not contaminated, overheated or expired and you should be fine. Kirkland, equate, any US generic should be good.