Dissolved in water. I buy it from Amazon: Amazon.com: Duda Energy 1sn 1 lb. Sodium Nitrate 99+% Pure Chile Saltpeter Gold Metal Refining Industrial Grade Glass Pottery Enamels : Arts, Crafts & Sewing
I've been using it for many years, seems to work. Doesn't drop my blood pressure by much, but some and seems to have positive effects when going hard. Super cheap, too. Maybe 12mmol NO3 per serving? Chem was a long time ago. My sources say don't take more than that one gram/day.