Some UG's don't carry it b/c it's a pain in the ass to make lol. Plus, no one uses test isocaproate or phenyl-propionate or decanoate by themselves, so those esters they have to buy exclusively for use in making sust. The only ester in sust that is used by itself is the prop. Most people would much rather just use a single ester like enth or cyp anyway, cheaper and easier to make, and easier to dose and keep stable blood levels. Sust really isn't that good a drug for bbers.