I've been taking this for close to five months but I held off writing the review for awhile because I wanted a chance to evaluate the effects. I chose this brand because I've taken other supplements from NOW Foods in the past and have found them to be safe. I think the value is excellent for the current price (about 6 capsules for a dollar). The product page recommends taking these with a source of essential fatty acids, and I do take it with an omega-3 supplement (Ovega, in my case, also sold on Amazon). CoQ10 is a fat-soluble compound, so the recommendation makes sense. I have a family history of heart problems and am especially concerned about the possibility of developing Hypertension in the future. I've already had a couple of high blood pressure readings at doctor's offices (possibly "white coat" syndrome, though). We're taking a watch-and-wait approach for now (decided upon after consultation with my doctor), as opposed to a prescription medication, but I'm trying to make several lifestyle changes to stave off what is likely to be genetically inevitable. CoQ10 deficiency has been associated with Hypertension. There's some evidence that hawthorn berry and/or CoQ10 may reduce Hypertension. Thus, this CoQ10 supplement. My at-home blood pressure readings have dropped a few points (both systolic and diastolic). Because I've increased the amount of exercise I do and have tried to reduce the salt in my diet, I can't attribute that solely to this supplement. However, 100 mg of CoQ10 daily is likely to be safe for healthy adults. I am not experiencing any of the gastrointestinal side effects that have been reported (nausea, loss of appetite, etc.). Please note that CoQ10 supplementation should be discontinued several weeks prior to surgical procedures, and that it may negatively interact with coumadin (warfarin), some cancer medications, and antihypertension drugs. My exercise tolerance is quite good; I'm currently on my second round of P90X3 and am able to complete both intense cardio and intense strength training workouts. If you are going to take a CoQ10 supplement, and especially if you are a vegetarian, this is a good one to try (from a reputable brand)