For thyroid issues, I’d recommend CNS, as I have 2 different MDs OK it (Dr. Rocky and a my integrative medicine PCP). However if your true goal is to gain muscle mass then I would do CBL and make sure you’re not over-training, doing too much cardio, limit no more that 4 hiit sessions a week, and it wouldn’t be bad idea to take some herbal adaptogens to lessen the effects of stress on your body. You have to work in relaxation and recovery twice as hard as you train, and not just lounging around (meditation, epson-salt baths, massage, walks, deep breathing, etc.). Best of luck!