I'm always concerned about the potency of supplements bought through Big Box stores, but I'm completely happy with this product. I'm a 61 year old guy, in decent shape for 185 lbs, but I'm getting a tad slow in da brain. (Everyone knows how good ginseng is for that sort of thing, amongst others.) At first, I tried two capsules. I felt more alert, but not as much as I'd've liked. The next day, I took four. Perfect! Not jittery, no stomach upset or other negatives. It lasts a good four hours, so I have taken that many ever since - between meals for economy's sake, as this might maximize the effect. (Might not, too.) My reading says that you can build up a tolerance to the effect after a while, so you can either up the dosage or lay off for a week or two. If you need to lay off, but still want to feel alert, try Irwin's Brain Alert (awesome stuff, also available at Walmart), or Rhodiola Rosea, specifically the Salidrosides component (an adaptogen which I haven't seen in Walmart). I'm also trying DMG (dimethylglycine - incredible science on this - though not on Walmart's shelves at my location). To sum up, Spring Valley's ginseng is awesome, and I'll buy it until if/when I find something better/cheaper, maybe in bulk.