I believe is a combination of the Ba alcohol and the purity of product. The more refined your tren is the less oxidized particles flowing in your system. Oxidized particles have a terrible allergic reaction in the lungs, your body will react by converting them into microscopic dust particles and getting them out of your system by coughing. Now remember just because the product is more refined it doesn't make it any more potent, so your tren is still good just not as refined. Here is something I do when I use tren, move the needle as little as possible after aspiration and inject really slow, even pause a couple of times for a split second , that helps. God bless you bro.