Ive taken in it once but only lasted like 2 weeks so cant really so much about it bought it from uniquemicals this was when they offered like 10mg/per ml in 30ml but now i think they upped it to 20 or 50 and pretty cheap reason why is i think is since its been proven that gw causes cancer in mice, their source mustve lowered prices but hey cancers really hard to get i mean people smoke for decades and die of something unrelated you know hahah