doesnt matter what color top is on the damn things, it matters how pure it is and whats on the inside. hell i can have my guy put purple tops on my generics if i want. the whole yellow top blue top thing is a gimmic. ive used both in the past going by people saying yellows were more potent, nope noticed no difference. only difference is truly between the generics and branded, genric yellows blue or grays are all the same.