I used anazao, switched to stroheckers and started to have a problem with the oil in the estrogen. I was injecting in my thigh, and had extreme pain a day or two after injecting, to the point of not being able to walk for 3 or 4 days. Thought it might be the type of oil but calls to both pharmacies confirmed they use the exact same stuff. I almost decided to switch back to patches. Spoke to a very nice pharmacist at stroeheckers who suggested I switch to injecting in my butt, rub the area vigorously right after injecting, and use very hot compresses (as hot as you can stand) for a while after that. I probably do so for 5-10 minutes. I guess it disperses the oil through the muscle? Haven't had much of a problem since. Still use thighs for the progesterone. It is the same volume of drug as the estrogen but some sort of non-oil suspension, and doesn't cause any problems at all, so I assume that it is the oil base of the estrogen. Don't know if this might help you, it saved me.