I think Source Naturals is one of the better classical formula brands available. I wish this Gingko extract was derived using organic plant, as Ginkgo can easily be contaminated with all pollution in Asia, as usually sourced there. Source Naturals promises premium purity, and I wish they have more certification to prove it. This is a brief review but I hope still helpful to you.
Taking supplements usually takes time to build up in your system, it makes it difficult to know if this is really helping me a lot or not. I also started several other supplements the same time. I do have to say that all the new supplements I'm taking seems to make me feel a bit healthier. More time will tell. Sorry but this is all I can say about this @ this time.