Originally Posted by PolishMan
Don't stop taking supplements, just modify your workout.
It sounds to me like your muscles are not being stressed enough to induce hypertrophy.
How many times in a day/week do you lift? When you are finished working out, do you feel as though you could easily do more? Are your goals to increase size or stamina? How many reps are you completing? How many sets?
If you really want to feel the effects of muscle hypertrophy and size is your goal, then try increasing the weight until you can only complete 3-6 reps and do as many sets as you possibly can.
If stamina is your goal then try 8-12 reps while increasing the amount of sets untill you can't do any more.
Anyways, good luck and keep us posted.