I've wondered about this as well. Whenever I go on tren, I usually notice a measurable strength gain within 3 to 4 days, and by the end of the week I get the night sweats, and am slightly more irritable. Before the end of the second week, I always look harder, and slightly more vascualar, so I find it amazing when guys are typing things such as "week 5 on fina and still nothing...." or "My fina finally kicked in on week 4...". Who knows perhaps it is just genetics. Maybe some of us are just more receptive, more ar's, less shbg. Hell, my first bulking cycle was nothing more than one amp of sust and 200 mg of deca a week for 8 week, and I gained a little over 40 ibs (Of course I ate like a pig, so half of it was fat and water, but still...). Compare that to a a good friend of mine who regularly dose a gram of test a week with any of the following; tren, eq, winny, hgh. After 4 years of juicing, he said he weighs 208 and is on 150 mg of prop/50mg of tren ed.. He is about 5'11 and is close to 20% bf if I had to make a guess. He is one of those guys who has to be 3 or 4 weeks into a cycle like that to add 20 ibs to his bench and gain 5 ibs. Its all genetics...