Pro-chem also have a new line out thats totally pain free (you probably wont see it for the next couple of months but my supplier gave me a batch to test). Their prop and as far as I can see their other products are made with ethyl oleate. On the bottle it also states the following solvents and their actual amounts, Benzyl benzoate, benzyl alcohol (as expected) but it also includes benzyl salicylate ( which keeps the depo in a liquid state and acts as an anti inflamatory) and Triethanolamine. Triethanolamine nutrilises propanoic acid which causes pain associated with prop esters. it also rasies pH and forms a complex with any carboxylic acid impurities during compounding so after filtering the compound is much more pure and painless.