Well, that's kinda a weird point about the grapeseed oil hurting. Didn't find that, my enanthate 500mg/ml hurt a bit, but the 400mg/ml deca didn't. I would imagine it was just the horomone. Now to the walnut oil, I got some refined walnut oil at a health store and it is great. It held my 500mg/ml enanthate at 1 or 2% BA, forget what I used, but I doubt I needed any of it. Also, I used 3% BA to make 100mg/ml tren acetate with it. The tren will DRAW with a 25g pin. Not too slow either. That's pretty damn good for oil, the grapeseed oil would probably take 10minutes to draw up with a 25g and it is fairly thin itslef. The two oils also have a similar color.