I am not sure if it is oil based - I have not given myself a dose yet of this Cyp. The 2nd pick shows a vial on its side so you can see the liquid. I notice it is very clear as opposed to the prop I have. I do have probably the worst pip I have had to date after maybe 10 total injections. The nurse was doing a walk-through on the injection and pinned my quad. She just jammed me and hit all 200 mg as fast as it would go in... I was kind of in shock. She did not warm it up or inject slowly or aspirate and she was giving me instructions... I had to walk about 2 miles last night to a high school football game. My leg felt like I had been hit with a 90 mph fastball... I tried riding a lifecylce for 40 minutes. I don't think it helped.