FukGenetics

whats up everybody? I just had a quick question. I was planning on cutting down a bit. I was gonna run clen/t3 cycle for the first time. I am 6'3 and 250lbs with 20%bf. I was wondering if clen would be effective at 20%bf? I have heard from someone that clen wouldn't do anything because 20%bf is too high for it to work. is this true? should I go for it?? Thanks you!