I have been injecting sustenon in a friends glutes for three weeks. Each time he had a pain for several days. I know for 100% certain that this was real Organon Sustenon. He has done cycles for at least 10 years, always sustenon in it. But never felt this pain. Does only Organon Sustenon causes this pain, or other sustenons to? If all sustenons causes pain, would that make the sustenons of previous cycles fakes (just plain testosteron with a ester)? He did grow on previous cycles (fast).