I did not start my son until he was 18 months on it. I want to say that he would never go a day without it. He is now 27 months old. They benefits I, therapsits, teachers, and family members notice are his high energy, alertness, cognitive and speech ability. Also it may help him with his muscle tone. He started it it the same day he did GH. So we never knew what was doing what, but once over 3 days he missed his COQ10. And he was floppy again. He was like a noodle when he tried to stand and his facial expression was droopy. His alertness was down and so was his speech. His therapist/preschool teacher asked me what was off about Luke and I said it was definitely the Coq10. She didn't know he was taking anything other than GH. I told her what it does and she agreed he needed to never skip. Also I have noticed that he may go on sleeping marathons (as I call them) when he doesn't get his dose. He is truely COQ10 deficient.
I do greatly regrett no giving it to him when he was in the NICU. I have to be honest-I was afraid to for many reasons.
Just a note of caution - Some formulations of CoQ10 include considerable amounts of Vitamin E. Too much vitamin E has been shown to have have harmful effects, so it's probably wise to pay attention to the formulation.