I refused to take a high powered drug about a 1 1/2 yrs. ago that had a risk of causing a worse problem when the diagnosis was AFIB by a cardiologist. It calms my heart and only takes 2 or 3 tablets a day to do it. My regular doctor is open to integrated medicine and agreed that the recommended drug was a risk in itself, so he suggested D-Ribose -- Bless him! I know it works, because I ran out once and my heart got all excited! I always keep one bottle ahead now so I don't run out again. I also take a baby aspirin every day. I tried Doctor's Best D-Ribose when iHerb had a free sample once...it was awful. Life Extension works so much better. Don't drop your meds because of this review, but its sure worth a talk to to doctor about it. This is great stuff and not just for athletes.