HRX Headaches?

So I take 3 HOT-ROX a day. 2 in the morning (empty stomach, half hour before eating) and again in the evening. Over the last few days I’ve had a constant mild headache, sort of a dull annoyance. Now obviously I am going to go back to 2 a day and see how that goes because I imagine I am over stimulating my nervous system. But I am curious as to what would be the physical cause of the headaches. Interaction with foods etc? I’m not taking HRX with caffeine. My supplements are HRX, BCAA, ON Multi Vitamin, ZMA, Melatonin, Creatine, Metabolic Drive and Fish Oil.

Any input?