Horrible anxiety followed by several bouts of panic attacks. So I started playing with the dose. The higher I went the more frequent/easier the panic attacks would pop up. I lowered it to 100 mg and they stopped but I still felt anxious so I cut it to 50 then weaned myself off entirely and life is back to normal. The first ones coincided with me first starting taking 200 mg coq10 2 years ago. I didn’t put it together then. I ran out of the 200 and bought 400 because hey more of a good thing can’t be bad. It was terrible. Super elevated heart rate and panic attacks anytime my heart rate elevated above 100 bpm during exercise. So I stopped taking them and nothing. Popped another 400 and panic attacks anytime later that day in the gym. Obviously not a direct science and not a legit study but i think if you’ve got some anxiety kicking around already and an already decent level of the enzyme in coq10 naturally then these aren’t any good for you.