Did you do a more traditional heavy volume training phase prior to DC?? I think HIT or versions of it such as DC trainig are great for hypertrophy for a while (say 2 months or so) as long as you did some traditonal heavy volume training (preferably without failure) before that. If you just jump into it the results hypertrophy aren't as great - at least in my experience. I found out alternating heavy volume/moderate intensity for 2 monts followed with some HIT variation (high intensity/low volume) for 2 months worked best for me personaly. Besides thatI feel that I absolutely need starch (potatoes and bananas work great for me probably because the potassium content) for best results. Sugar just doesn't do it fot me.I wouldn't necessarily recommend what I do because I too suffer from fatigue, irritability. My temps/pulse could be higher. I suspect my metabolism is not where it could be (finasteride has something to do with it)
Anyways my routine I have seen the best results with for gaining muscle is Dante's Doggcrapp program. How to Build 50 Pounds of Muscle in 12 Months | T Nation This is not a very well known plan but a lot of Mr Olympia's have used it or something similar. There are two versions, one with more volume that is intended for steroid users and one with about half the work for "natural athletes". My take on it is this: 2 day split, day 1: push day, day 2: pull day. Day A, then, has chest, quads, triceps, shoulders. Day B is back, biceps, hamstrings, traps. The trick is that you do only one working set per muscle group, but do 2 light warm up sets first. On the "working set" you give it your best effort and really bring the pain. It's a drop-down tri-set which means that you do 10 controlled reps, drop the weight down about 15 %, do 8 more reps, drop the weight, do 6 reps. After I do an intense set like this for each muscle group, I do stretching excercises which help to stretch out and expand the muscle fascia. This should engorge the muscles with blood I suppose. So for chest I would take 40 lbs dumbells and do slow, controlled flies with a couple seconds pause at the bottom, and do just one or two sets with just arm stretching. For quads I might do some very slow negative reps on the leg press with light weight and just one leg.
The trick with this program is to only do one "insane" set per muscle group and do a lot of stretching, and its a 4 day cycle instead of the typical 7 days. So its push day, pull day, cardio/abs/calves day, rest day, then repeat using different excercises. Next cycle use different excercises again, and then on the 4th cycle repeat the excercises you did the first time and you should see progress.
I stopped taking this program seriously because I don't get a NO pump anymore since peating and also I just don't care about being very muscular anymore. However this was the best muscle-building program I ever tried, especially if you are eating tons of chicken breast and whey (Please don't do that).These days I just want to maintain a nice solid relatively lean build. So if I was 190-200 lbs, 10 % bodyfat that would be just awesome.